crates/features/src/mailflow/detectors/africa.rs

@@ -0,0 +1,49 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Coffey Labs
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+//! African identifiers (§2.3): South Africa's ID number.
+
+use super::{Detector, Findings, Region, Strength, checks, valid_short_date};
+use regex::Regex;
+use std::sync::LazyLock;
+
+pub static DETECTORS: &[Detector] = &[Detector::new(
+    "za-id",
+    "South Africa: ID number",
+    Region::Africa,
+    Strength::Checked,
+    za_id,
+)];
+
+/// Birth date `YYMMDD`, four digits, citizenship (0, 1 or 2), 8 or 9, a Luhn
+/// check digit. The date and the two fixed digits make it strong enough to
+/// count alone.
+static ZA_ID: LazyLock<Regex> = LazyLock::new(|| {
+    Regex::new(r"\b(\d{2})(\d{2})(\d{2})\d{4}[012][89]\d\b").expect("detector pattern")
+});
+
+fn za_id(text: &str, findings: &mut Findings) {
+    for c in ZA_ID.captures_iter(text) {
+        let n = &c[0];
+        let num = |s: &str| s.parse::<u32>().unwrap_or(0);
+        if valid_short_date(num(&c[1]), num(&c[2]), num(&c[3])) && checks::luhn(n) {
+            findings.insert(n);
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::mailflow::detectors::by_id;
+
+    #[test]
+    fn south_africa() {
+        let detector = by_id("za-id").unwrap();
+        assert_eq!(detector.count("ID 8001015009087"), 1);
+        assert_eq!(detector.count("8001015009088"), 0);
+        assert_eq!(detector.count("8013015009087"), 0);
+    }
+}

crates/features/src/mailflow/detectors/americas.rs

@@ -0,0 +1,172 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Coffey Labs
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+//! Identifiers from the Americas outside the US and Canada (§2.3): Brazil's
+//! CPF and CNPJ, and Mexico's CURP.
+
+use super::{Detector, Findings, Region, Strength, digit_values, valid_short_date, word_near};
+use regex::Regex;
+use std::sync::LazyLock;
+
+pub static DETECTORS: &[Detector] = &[
+    Detector::new(
+        "br-cpf",
+        "Brazil: CPF",
+        Region::Americas,
+        Strength::Checked,
+        br_cpf,
+    ),
+    Detector::new(
+        "br-cnpj",
+        "Brazil: CNPJ",
+        Region::Americas,
+        Strength::Checked,
+        br_cnpj,
+    ),
+    Detector::new(
+        "mx-curp",
+        "Mexico: CURP",
+        Region::Americas,
+        Strength::Checked,
+        mx_curp,
+    ),
+];
+
+fn re(pattern: &str) -> Regex {
+    Regex::new(pattern).expect("detector pattern")
+}
+
+/// Brazil's mod 11 check digit over `digits` with `weights`.
+fn br_check(digits: &[u32], weights: &[u32]) -> u32 {
+    match digits.iter().zip(weights).map(|(a, w)| a * w).sum::<u32>() % 11 {
+        0 | 1 => 0,
+        r => 11 - r,
+    }
+}
+
+/// `111.444.777-35`, or eleven bare digits.
+static CPF: LazyLock<Regex> = LazyLock::new(|| re(r"\b\d{3}(\.?)\d{3}(\.?)\d{3}(-?)\d{2}\b"));
+
+pub fn cpf_valid(n: &str) -> bool {
+    let d = digit_values(n);
+    // A run of one digit passes the arithmetic but is never issued
+    d.len() == 11
+        && d.iter().any(|x| *x != d[0])
+        && br_check(&d[..9], &[10, 9, 8, 7, 6, 5, 4, 3, 2]) == d[9]
+        && br_check(&d[..10], &[11, 10, 9, 8, 7, 6, 5, 4, 3, 2]) == d[10]
+}
+
+const CPF_WORDS: &[&str] = &[
+    "cpf",
+    "cadastro de pessoas físicas",
+    "cadastro de pessoa física",
+];
+
+fn br_cpf(text: &str, findings: &mut Findings) {
+    for c in CPF.captures_iter(text) {
+        let whole = c.get(0).unwrap();
+        let written = &c[1] == "." && &c[2] == "." && &c[3] == "-";
+        let n: String = whole
+            .as_str()
+            .chars()
+            .filter(char::is_ascii_digit)
+            .collect();
+        if cpf_valid(&n) && (written || word_near(text, whole.start(), whole.end(), CPF_WORDS)) {
+            findings.insert(n);
+        }
+    }
+}
+
+/// `11.222.333/0001-81`, or fourteen bare digits.
+static CNPJ: LazyLock<Regex> =
+    LazyLock::new(|| re(r"\b\d{2}(\.?)\d{3}(\.?)\d{3}(/?)\d{4}(-?)\d{2}\b"));
+
+pub fn cnpj_valid(n: &str) -> bool {
+    let d = digit_values(n);
+    d.len() == 14
+        && d.iter().any(|x| *x != d[0])
+        && br_check(&d[..12], &[5, 4, 3, 2, 9, 8, 7, 6, 5, 4, 3, 2]) == d[12]
+        && br_check(&d[..13], &[6, 5, 4, 3, 2, 9, 8, 7, 6, 5, 4, 3, 2]) == d[13]
+}
+
+const CNPJ_WORDS: &[&str] = &["cnpj", "cadastro nacional da pessoa jurídica"];
+
+fn br_cnpj(text: &str, findings: &mut Findings) {
+    for c in CNPJ.captures_iter(text) {
+        let whole = c.get(0).unwrap();
+        let written = &c[1] == "." && &c[2] == "." && &c[3] == "/" && &c[4] == "-";
+        let n: String = whole
+            .as_str()
+            .chars()
+            .filter(char::is_ascii_digit)
+            .collect();
+        if cnpj_valid(&n) && (written || word_near(text, whole.start(), whole.end(), CNPJ_WORDS)) {
+            findings.insert(n);
+        }
+    }
+}
+
+/// Four letters, the birth date, sex (H, M or X), the state, three
+/// consonants, a character that tells the century apart, the check digit.
+static CURP: LazyLock<Regex> = LazyLock::new(|| {
+    re(r"(?i)\b[A-Z]{4}(\d{2})(\d{2})(\d{2})[HMX][A-Z]{2}[B-DF-HJ-NP-TV-Z]{3}[A-Z0-9]\d\b")
+});
+
+/// RENAPO's check: each character's place in `0-9 A-N Ñ O-Z`, weighted 18
+/// down to 2; the digit is 10 minus the sum mod 10 (10 becomes 0).
+pub fn curp_valid(curp: &str) -> bool {
+    const ALPHABET: &str = "0123456789ABCDEFGHIJKLMNÑOPQRSTUVWXYZ";
+    let mut sum = 0u32;
+    for (i, c) in curp.chars().take(17).enumerate() {
+        let Some(value) = ALPHABET.chars().position(|a| a == c) else {
+            return false;
+        };
+        sum += value as u32 * (18 - i as u32);
+    }
+    curp.chars().nth(17).and_then(|c| c.to_digit(10)) == Some((10 - sum % 10) % 10)
+}
+
+fn mx_curp(text: &str, findings: &mut Findings) {
+    for c in CURP.captures_iter(text) {
+        let curp = c[0].to_ascii_uppercase();
+        if valid_short_date(num(&c[1]), num(&c[2]), num(&c[3])) && curp_valid(&curp) {
+            findings.insert(curp);
+        }
+    }
+}
+
+fn num(s: &str) -> u32 {
+    s.parse().unwrap_or(0)
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::mailflow::detectors::by_id;
+
+    fn count(id: &str, text: &str) -> usize {
+        by_id(id).unwrap().count(text)
+    }
+
+    #[test]
+    fn brazil() {
+        assert_eq!(count("br-cpf", "CPF 111.444.777-35"), 1);
+        assert_eq!(count("br-cpf", "111.444.777-36"), 0);
+        assert_eq!(count("br-cpf", "pedido 11144477735"), 0);
+        assert_eq!(count("br-cpf", "cpf: 11144477735"), 1);
+        assert_eq!(count("br-cpf", "CPF 111.111.111-11"), 0);
+        assert_eq!(count("br-cnpj", "11.222.333/0001-81"), 1);
+        assert_eq!(count("br-cnpj", "11.222.333/0001-82"), 0);
+        assert_eq!(count("br-cnpj", "CNPJ 11222333000181"), 1);
+    }
+
+    #[test]
+    fn mexico() {
+        // python-stdnum's documented example
+        assert_eq!(count("mx-curp", "CURP BOXW310820HNERXN09"), 1);
+        assert_eq!(count("mx-curp", "BOXW310820HNERXN08"), 0);
+        assert_eq!(count("mx-curp", "BOXW311320HNERXN09"), 0);
+    }
+}

crates/features/src/mailflow/detectors/any.rs

@@ -6,7 +6,9 @@
 
 //! Detectors that aren't tied to one country (§2.3, region "Any").
 
-use super::{Detector, Findings, Region, Strength, checks, digits, stands_alone, word_near};
+use super::{
+    Detector, Findings, Region, Strength, checks, digits, stands_alone, valid_date, word_near,
+};
 use regex::Regex;
 use std::sync::LazyLock;
 
@@ -295,19 +297,6 @@ const BIRTH_WORDS: &[&str] = &[
     "nascimento",
 ];
 
-fn valid_date(year: u32, month: u32, day: u32) -> bool {
-    let days = match month {
-        1 | 3 | 5 | 7 | 8 | 10 | 12 => 31,
-        4 | 6 | 9 | 11 => 30,
-        2 if year.is_multiple_of(4) && (!year.is_multiple_of(100) || year.is_multiple_of(400)) => {
-            29
-        }
-        2 => 28,
-        _ => return false,
-    };
-    (1900..=2100).contains(&year) && (1..=days).contains(&day)
-}
-
 fn month_number(name: &str) -> u32 {
     const MONTHS: [&str; 12] = [
         "jan", "feb", "mar", "apr", "may", "jun", "jul", "aug", "sep", "oct", "nov", "dec",

crates/features/src/mailflow/detectors/asia.rs

@@ -0,0 +1,281 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Coffey Labs
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+//! Asian identifiers (§2.3): India's Aadhaar and PAN, China's resident ID,
+//! Japan's My Number, Singapore's NRIC and FIN, and South Korea's resident
+//! registration number.
+
+use super::{
+    Detector, Findings, Region, Strength, digit_values, valid_date, valid_short_date, word_near,
+};
+use regex::Regex;
+use std::sync::LazyLock;
+
+pub static DETECTORS: &[Detector] = &[
+    Detector::new(
+        "in-aadhaar",
+        "India: Aadhaar",
+        Region::Asia,
+        Strength::Checked,
+        in_aadhaar,
+    ),
+    Detector::new(
+        "in-pan",
+        "India: PAN",
+        Region::Asia,
+        Strength::NeedsWord,
+        in_pan,
+    ),
+    Detector::new(
+        "cn-resident-id",
+        "China: resident ID",
+        Region::Asia,
+        Strength::Checked,
+        cn_resident_id,
+    ),
+    Detector::new(
+        "jp-my-number",
+        "Japan: My Number",
+        Region::Asia,
+        Strength::Checked,
+        jp_my_number,
+    ),
+    Detector::new(
+        "sg-nric",
+        "Singapore: NRIC and FIN",
+        Region::Asia,
+        Strength::Checked,
+        sg_nric,
+    ),
+    Detector::new(
+        "kr-rrn",
+        "South Korea: resident registration number",
+        Region::Asia,
+        Strength::NeedsWord,
+        kr_rrn,
+    ),
+];
+
+fn re(pattern: &str) -> Regex {
+    Regex::new(pattern).expect("detector pattern")
+}
+
+/// Twelve digits written in fours, or bare.
+static TWELVE: LazyLock<Regex> = LazyLock::new(|| re(r"\b(\d{4})( ?)(\d{4})( ?)(\d{4})\b"));
+
+const VERHOEFF_D: [[u8; 10]; 10] = [
+    [0, 1, 2, 3, 4, 5, 6, 7, 8, 9],
+    [1, 2, 3, 4, 0, 6, 7, 8, 9, 5],
+    [2, 3, 4, 0, 1, 7, 8, 9, 5, 6],
+    [3, 4, 0, 1, 2, 8, 9, 5, 6, 7],
+    [4, 0, 1, 2, 3, 9, 5, 6, 7, 8],
+    [5, 9, 8, 7, 6, 0, 4, 3, 2, 1],
+    [6, 5, 9, 8, 7, 1, 0, 4, 3, 2],
+    [7, 6, 5, 9, 8, 2, 1, 0, 4, 3],
+    [8, 7, 6, 5, 9, 3, 2, 1, 0, 4],
+    [9, 8, 7, 6, 5, 4, 3, 2, 1, 0],
+];
+const VERHOEFF_P: [[u8; 10]; 8] = [
+    [0, 1, 2, 3, 4, 5, 6, 7, 8, 9],
+    [1, 5, 7, 6, 2, 8, 3, 0, 9, 4],
+    [5, 8, 0, 3, 7, 9, 6, 1, 4, 2],
+    [8, 9, 1, 6, 0, 4, 3, 5, 2, 7],
+    [9, 4, 5, 3, 1, 2, 6, 8, 7, 0],
+    [4, 2, 8, 6, 5, 7, 3, 9, 0, 1],
+    [2, 7, 9, 3, 8, 0, 6, 4, 1, 5],
+    [7, 0, 4, 6, 9, 1, 3, 2, 5, 8],
+];
+
+/// The Verhoeff check (dihedral group D5).
+pub fn verhoeff(n: &str) -> bool {
+    let mut c = 0u8;
+    for (i, b) in n.bytes().rev().enumerate() {
+        c = VERHOEFF_D[c as usize][VERHOEFF_P[i % 8][(b - b'0') as usize] as usize];
+    }
+    c == 0
+}
+
+const AADHAAR_WORDS: &[&str] = &["aadhaar", "aadhar", "uidai", "uid"];
+
+fn in_aadhaar(text: &str, findings: &mut Findings) {
+    for c in TWELVE.captures_iter(text) {
+        let whole = c.get(0).unwrap();
+        let n = format!("{}{}{}", &c[1], &c[3], &c[5]);
+        let written = &c[2] == " " && &c[4] == " ";
+        // Never starts with 0 or 1
+        if !n.starts_with(['0', '1'])
+            && verhoeff(&n)
+            && (written || word_near(text, whole.start(), whole.end(), AADHAAR_WORDS))
+        {
+            findings.insert(n);
+        }
+    }
+}
+
+/// Five letters (the fourth names the holder's type), four digits, a letter.
+static PAN: LazyLock<Regex> = LazyLock::new(|| re(r"\b[A-Z]{3}[ABCFGHLJPTK][A-Z]\d{4}[A-Z]\b"));
+
+const PAN_WORDS: &[&str] = &["pan", "pan card", "permanent account number", "income tax"];
+
+fn in_pan(text: &str, findings: &mut Findings) {
+    for m in PAN.find_iter(text) {
+        if word_near(text, m.start(), m.end(), PAN_WORDS) {
+            findings.insert(m.as_str());
+        }
+    }
+}
+
+/// Region, birth date `YYYYMMDD`, sequence, then the ISO 7064 MOD 11-2
+/// check (0–9 or X).
+static CN_ID: LazyLock<Regex> =
+    LazyLock::new(|| re(r"(?i)\b[1-8]\d{5}(\d{4})(\d{2})(\d{2})\d{3}[\dX]\b"));
+
+pub fn cn_id_valid(id: &str) -> bool {
+    const WEIGHTS: [u32; 17] = [7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2];
+    const CHECKS: &[u8] = b"10X98765432";
+    let sum: u32 = digit_values(&id[..17])
+        .iter()
+        .zip(WEIGHTS)
+        .map(|(a, w)| a * w)
+        .sum();
+    CHECKS[(sum % 11) as usize] == id.as_bytes()[17].to_ascii_uppercase()
+}
+
+fn cn_resident_id(text: &str, findings: &mut Findings) {
+    for c in CN_ID.captures_iter(text) {
+        let id = c[0].to_ascii_uppercase();
+        let (y, m, d) = (num(&c[1]), num(&c[2]), num(&c[3]));
+        if valid_date(y, m, d) && cn_id_valid(&id) {
+            findings.insert(id);
+        }
+    }
+}
+
+/// My Number: weights 2–7 then 2–6 from the right; a remainder of 0 or 1
+/// gives 0, else 11 minus it.
+pub fn my_number_valid(n: &str) -> bool {
+    let d = digit_values(n);
+    let sum: u32 = (1..=11)
+        .map(|i| d[11 - i] * if i <= 6 { i as u32 + 1 } else { i as u32 - 5 })
+        .sum();
+    let check = match sum % 11 {
+        0 | 1 => 0,
+        r => 11 - r,
+    };
+    check == d[11]
+}
+
+const MY_NUMBER_WORDS: &[&str] = &[
+    "my number",
+    "mynumber",
+    "マイナンバー",
+    "個人番号",
+    "kojin bango",
+];
+
+fn jp_my_number(text: &str, findings: &mut Findings) {
+    for c in TWELVE.captures_iter(text) {
+        let whole = c.get(0).unwrap();
+        let n = format!("{}{}{}", &c[1], &c[3], &c[5]);
+        let written = &c[2] == " " && &c[4] == " ";
+        if my_number_valid(&n)
+            && (written || word_near(text, whole.start(), whole.end(), MY_NUMBER_WORDS))
+        {
+            findings.insert(n);
+        }
+    }
+}
+
+static NRIC: LazyLock<Regex> = LazyLock::new(|| re(r"(?i)\b([STFGM])(\d{7})([A-Z])\b"));
+
+/// Weights 2, 7, 6, 5, 4, 3, 2; T and G add 4, M adds 3; each series has its
+/// own table of check letters.
+fn nric_valid(prefix: u8, digits: &str, check: u8) -> bool {
+    let sum: u32 = digit_values(digits)
+        .iter()
+        .zip([2, 7, 6, 5, 4, 3, 2])
+        .map(|(a, w)| a * w)
+        .sum::<u32>()
+        + match prefix {
+            b'T' | b'G' => 4,
+            b'M' => 3,
+            _ => 0,
+        };
+    let table: &[u8] = match prefix {
+        b'S' | b'T' => b"JZIHGFEDCBA",
+        b'F' | b'G' => b"XWUTRQPNMLK",
+        _ => b"KLJNPQRTUWX",
+    };
+    table[(sum % 11) as usize] == check
+}
+
+fn sg_nric(text: &str, findings: &mut Findings) {
+    for c in NRIC.captures_iter(text) {
+        let id = c[0].to_ascii_uppercase();
+        let bytes = id.as_bytes();
+        if nric_valid(bytes[0], &c[2], bytes[8]) {
+            findings.insert(id);
+        }
+    }
+}
+
+/// `YYMMDD-GNNNNNN`, the seventh digit giving sex and century.
+static RRN: LazyLock<Regex> = LazyLock::new(|| re(r"\b(\d{2})(\d{2})(\d{2})-?([1-8])\d{6}\b"));
+
+const RRN_WORDS: &[&str] = &["주민등록번호", "주민번호", "resident registration", "rrn"];
+
+fn kr_rrn(text: &str, findings: &mut Findings) {
+    for c in RRN.captures_iter(text) {
+        let whole = c.get(0).unwrap();
+        if valid_short_date(num(&c[1]), num(&c[2]), num(&c[3]))
+            && word_near(text, whole.start(), whole.end(), RRN_WORDS)
+        {
+            findings.insert(whole.as_str().replace('-', ""));
+        }
+    }
+}
+
+fn num(s: &str) -> u32 {
+    s.parse().unwrap_or(0)
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::mailflow::detectors::by_id;
+
+    fn count(id: &str, text: &str) -> usize {
+        by_id(id).unwrap().count(text)
+    }
+
+    #[test]
+    fn india() {
+        assert_eq!(count("in-aadhaar", "2345 6789 0124"), 1);
+        assert_eq!(count("in-aadhaar", "2345 6789 0125"), 0);
+        assert_eq!(count("in-aadhaar", "order 234567890124"), 0);
+        assert_eq!(count("in-aadhaar", "Aadhaar 234567890124"), 1);
+        assert_eq!(count("in-pan", "PAN: ABCPE1234F"), 1);
+        assert_eq!(count("in-pan", "ABCPE1234F"), 0);
+    }
+
+    #[test]
+    fn china_japan() {
+        assert_eq!(count("cn-resident-id", "11010519491231002X"), 1);
+        assert_eq!(count("cn-resident-id", "110105194912310021"), 0);
+        assert_eq!(count("cn-resident-id", "11010519491331002X"), 0);
+        assert_eq!(count("jp-my-number", "1234 5678 9018"), 1);
+        assert_eq!(count("jp-my-number", "1234 5678 9017"), 0);
+        assert_eq!(count("jp-my-number", "マイナンバー 123456789018"), 1);
+    }
+
+    #[test]
+    fn singapore_korea() {
+        assert_eq!(count("sg-nric", "S1234567D and T1234567J"), 2);
+        assert_eq!(count("sg-nric", "S1234567E"), 0);
+        assert_eq!(count("kr-rrn", "주민등록번호 800101-1234567"), 1);
+        assert_eq!(count("kr-rrn", "800101-1234567"), 0);
+        assert_eq!(count("kr-rrn", "RRN 801301-1234567"), 0);
+    }
+}

crates/features/src/mailflow/detectors/australia.rs

@@ -0,0 +1,128 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Coffey Labs
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+//! Australian identifiers (§2.3): the ATO's Tax File Number and the Medicare
+//! card number.
+
+use super::{Detector, Findings, Region, Strength, word_near};
+use regex::Regex;
+use std::sync::LazyLock;
+
+pub static DETECTORS: &[Detector] = &[
+    Detector::new(
+        "au-tfn",
+        "Australian Tax File Number",
+        Region::Australia,
+        Strength::Checked,
+        tfn,
+    ),
+    Detector::new(
+        "au-medicare",
+        "Australian Medicare number",
+        Region::Australia,
+        Strength::Checked,
+        medicare,
+    ),
+];
+
+fn re(pattern: &str) -> Regex {
+    Regex::new(pattern).expect("detector pattern")
+}
+
+/// `NNN NNN NNN` stands alone; bare digits (eight or nine) need a word.
+static TFN: LazyLock<Regex> = LazyLock::new(|| re(r"\b(\d{3})( ?)(\d{3})( ?)(\d{2,3})\b"));
+
+/// Weighted sum mod 11, with the ATO's weights for 9- and 8-digit numbers.
+pub fn tfn_valid(n: &str) -> bool {
+    let weights: &[u32] = match n.len() {
+        9 => &[1, 4, 3, 7, 5, 8, 6, 9, 10],
+        8 => &[10, 7, 8, 4, 6, 3, 5, 1],
+        _ => return false,
+    };
+    n.bytes()
+        .zip(weights)
+        .map(|(b, w)| u32::from(b - b'0') * w)
+        .sum::<u32>()
+        % 11
+        == 0
+}
+
+const TFN_WORDS: &[&str] = &["tfn", "tax file number", "tax file no"];
+
+fn tfn(text: &str, findings: &mut Findings) {
+    for c in TFN.captures_iter(text) {
+        let whole = c.get(0).unwrap();
+        let n = format!("{}{}{}", &c[1], &c[3], &c[5]);
+        let written = n.len() == 9 && c[2] == *" " && c[4] == *" ";
+        if tfn_valid(&n) && (written || word_near(text, whole.start(), whole.end(), TFN_WORDS)) {
+            findings.insert(n);
+        }
+    }
+}
+
+/// `NNNN NNNNN N` (and an optional issue number) stands alone; bare digits
+/// need a word.
+static MEDICARE: LazyLock<Regex> =
+    LazyLock::new(|| re(r"\b([2-6]\d{3})( ?)(\d{5})( ?)(\d)(?:[ -]?\d)?\b"));
+
+/// The ninth digit is the weighted sum (1, 3, 7, 9, 1, 3, 7, 9) of the first
+/// eight, mod 10.
+pub fn medicare_valid(n: &str) -> bool {
+    let d: Vec<u32> = n.bytes().map(|b| u32::from(b - b'0')).collect();
+    d.len() >= 9
+        && d[..8]
+            .iter()
+            .zip([1, 3, 7, 9, 1, 3, 7, 9])
+            .map(|(a, w)| a * w)
+            .sum::<u32>()
+            % 10
+            == d[8]
+}
+
+const MEDICARE_WORDS: &[&str] = &[
+    "medicare",
+    "medicare card",
+    "medicare no",
+    "medicare number",
+];
+
+fn medicare(text: &str, findings: &mut Findings) {
+    for c in MEDICARE.captures_iter(text) {
+        let whole = c.get(0).unwrap();
+        let n = format!("{}{}{}", &c[1], &c[3], &c[5]);
+        let written = c[2] == *" " && c[4] == *" ";
+        if medicare_valid(&n)
+            && (written || word_near(text, whole.start(), whole.end(), MEDICARE_WORDS))
+        {
+            findings.insert(n);
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::mailflow::detectors::by_id;
+
+    fn count(id: &str, text: &str) -> usize {
+        by_id(id).unwrap().count(text)
+    }
+
+    #[test]
+    fn tax_file_numbers() {
+        assert_eq!(count("au-tfn", "TFN 123 456 782"), 1);
+        assert_eq!(count("au-tfn", "123 456 789"), 0);
+        assert_eq!(count("au-tfn", "order 123456782"), 0);
+        assert_eq!(count("au-tfn", "tax file number 123456782"), 1);
+    }
+
+    #[test]
+    fn medicare_numbers() {
+        assert_eq!(count("au-medicare", "2123 45670 1"), 1);
+        assert_eq!(count("au-medicare", "2123 45671 1"), 0);
+        assert_eq!(count("au-medicare", "ref 2123456701"), 0);
+        assert_eq!(count("au-medicare", "Medicare 2123456701"), 1);
+    }
+}

crates/features/src/mailflow/detectors/canada.rs

@@ -0,0 +1,66 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Coffey Labs
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+//! Canadian identifiers (§2.3): the Social Insurance Number.
+
+use super::{Detector, Findings, Region, Strength, checks, word_near};
+use regex::Regex;
+use std::sync::LazyLock;
+
+pub static DETECTORS: &[Detector] = &[Detector::new(
+    "ca-sin",
+    "Canadian Social Insurance Number",
+    Region::Canada,
+    Strength::Checked,
+    sin,
+)];
+
+/// `NNN NNN NNN` or `NNN-NNN-NNN` stands alone; nine bare digits need a word.
+static SIN: LazyLock<Regex> = LazyLock::new(|| {
+    Regex::new(r"\b(\d{3})([ -]?)(\d{3})([ -]?)(\d{3})\b").expect("detector pattern")
+});
+
+const SIN_WORDS: &[&str] = &[
+    "sin",
+    "social insurance",
+    "nas",
+    "numéro d'assurance sociale",
+    "assurance sociale",
+];
+
+fn sin(text: &str, findings: &mut Findings) {
+    for c in SIN.captures_iter(text) {
+        let whole = c.get(0).unwrap();
+        let n = format!("{}{}{}", &c[1], &c[3], &c[5]);
+        let written = !c[2].is_empty() && c[2] == c[4];
+        // 0 and 8 are never issued as a first digit
+        if !n.starts_with(['0', '8'])
+            && checks::luhn(&n)
+            && (written || word_near(text, whole.start(), whole.end(), SIN_WORDS))
+        {
+            findings.insert(n);
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::mailflow::detectors::by_id;
+
+    fn count(text: &str) -> usize {
+        by_id("ca-sin").unwrap().count(text)
+    }
+
+    #[test]
+    fn social_insurance_numbers() {
+        assert_eq!(count("130 692 544 and 193-456-787"), 2);
+        assert_eq!(count("130 692 545"), 0);
+        // The government's printed example starts with 0, never issued
+        assert_eq!(count("046 454 286"), 0);
+        assert_eq!(count("order 130692544"), 0);
+        assert_eq!(count("SIN: 130692544"), 1);
+    }
+}

crates/features/src/mailflow/detectors/checks.rs

@@ -25,7 +25,7 @@ pub fn luhn(digits: &str) -> bool {
             }
         })
         .sum();
-    sum % 10 == 0
+    sum.is_multiple_of(10)
 }
 
 /// ISO 13616 IBAN lengths, by country, from the IBAN registry.

crates/features/src/mailflow/detectors/eu.rs

@@ -0,0 +1,646 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Coffey Labs
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+//! European Union national identifiers (§2.3), each from its issuer's
+//! published rules. An identifier that is only digits and whose check a
+//! random number passes often (mod 10, mod 11) counts alone only in its
+//! written form, and as bare digits only beside a word.
+
+use super::{
+    Detector, Findings, Region, Strength, checks, digit_values, stands_alone, valid_short_date,
+    word_near,
+};
+use regex::Regex;
+use std::sync::LazyLock;
+
+pub static DETECTORS: &[Detector] = &[
+    Detector::new(
+        "de-tax-id",
+        "Germany: tax ID (Steuer-ID)",
+        Region::Eu,
+        Strength::Checked,
+        de_tax_id,
+    ),
+    Detector::new(
+        "de-id-card",
+        "Germany: ID card number",
+        Region::Eu,
+        Strength::Checked,
+        de_id_card,
+    ),
+    Detector::new(
+        "fr-nir",
+        "France: social security number (NIR)",
+        Region::Eu,
+        Strength::Checked,
+        fr_nir,
+    ),
+    Detector::new(
+        "es-dni-nie",
+        "Spain: DNI and NIE",
+        Region::Eu,
+        Strength::Checked,
+        es_dni_nie,
+    ),
+    Detector::new(
+        "it-codice-fiscale",
+        "Italy: codice fiscale",
+        Region::Eu,
+        Strength::Checked,
+        it_codice_fiscale,
+    ),
+    Detector::new(
+        "nl-bsn",
+        "Netherlands: BSN",
+        Region::Eu,
+        Strength::Checked,
+        nl_bsn,
+    ),
+    Detector::new(
+        "be-national-number",
+        "Belgium: national number",
+        Region::Eu,
+        Strength::Checked,
+        be_national_number,
+    ),
+    Detector::new(
+        "pl-pesel",
+        "Poland: PESEL",
+        Region::Eu,
+        Strength::Checked,
+        pl_pesel,
+    ),
+    Detector::new(
+        "se-personnummer",
+        "Sweden: personnummer",
+        Region::Eu,
+        Strength::Checked,
+        se_personnummer,
+    ),
+    Detector::new(
+        "dk-cpr",
+        "Denmark: CPR number",
+        Region::Eu,
+        Strength::NeedsWord,
+        dk_cpr,
+    ),
+    Detector::new(
+        "fi-hetu",
+        "Finland: personal identity code",
+        Region::Eu,
+        Strength::Checked,
+        fi_hetu,
+    ),
+    Detector::new(
+        "ie-pps",
+        "Ireland: PPS number",
+        Region::Eu,
+        Strength::Checked,
+        ie_pps,
+    ),
+    Detector::new(
+        "pt-nif",
+        "Portugal: NIF",
+        Region::Eu,
+        Strength::Checked,
+        pt_nif,
+    ),
+    Detector::new(
+        "at-svnr",
+        "Austria: social insurance number",
+        Region::Eu,
+        Strength::Checked,
+        at_svnr,
+    ),
+];
+
+fn re(pattern: &str) -> Regex {
+    Regex::new(pattern).expect("detector pattern")
+}
+
+fn num(s: &str) -> u32 {
+    s.parse().unwrap_or(0)
+}
+
+// --- Germany --------------------------------------------------------------
+
+/// Eleven digits, written `86 095 742 719` on the BZSt's letters.
+static DE_TAX: LazyLock<Regex> = LazyLock::new(|| re(r"\b\d{2}( ?)\d{3}( ?)\d{3}( ?)\d{3}\b"));
+
+/// ISO 7064 MOD 11,10; no leading zero; in the first ten digits one digit
+/// appears two or three times and every other at most once.
+pub fn de_tax_id_valid(n: &str) -> bool {
+    let d = digit_values(n);
+    if d.len() != 11 || d[0] == 0 {
+        return false;
+    }
+    let mut counts = [0u8; 10];
+    for &x in &d[..10] {
+        counts[x as usize] += 1;
+    }
+    let repeated = counts.iter().filter(|&&c| c >= 2).count();
+    if repeated != 1 || counts.iter().any(|&c| c > 3) {
+        return false;
+    }
+    let mut product = 10;
+    for &x in &d[..10] {
+        let mut sum = (x + product) % 10;
+        if sum == 0 {
+            sum = 10;
+        }
+        product = (2 * sum) % 11;
+    }
+    let check = match 11 - product {
+        10 => 0,
+        c => c,
+    };
+    check == d[10]
+}
+
+const DE_TAX_WORDS: &[&str] = &[
+    "steuer-id",
+    "steueridentifikationsnummer",
+    "steuerliche identifikationsnummer",
+    "idnr",
+    "identifikationsnummer",
+    "tax id",
+];
+
+fn de_tax_id(text: &str, findings: &mut Findings) {
+    for c in DE_TAX.captures_iter(text) {
+        let whole = c.get(0).unwrap();
+        let written = [&c[1], &c[2], &c[3]].iter().all(|s| *s == " ");
+        let n: String = whole.as_str().replace(' ', "");
+        if de_tax_id_valid(&n)
+            && (written || word_near(text, whole.start(), whole.end(), DE_TAX_WORDS))
+        {
+            findings.insert(n);
+        }
+    }
+}
+
+/// The ID card's document number: a letter from the card's alphabet, eight
+/// more characters from it, then the check digit.
+static DE_ID: LazyLock<Regex> =
+    LazyLock::new(|| re(r"\b[CFGHJKLMNPRTVWXYZ][CFGHJKLMNPRTVWXYZ0-9]{8}\d\b"));
+
+/// ICAO 9303 check digit: weights 7, 3, 1; letters A=10 … Z=35.
+pub fn icao_check(chars: &str, check: u32) -> bool {
+    let value = |c: char| c.to_digit(10).unwrap_or_else(|| c as u32 - 'A' as u32 + 10);
+    let sum: u32 = chars
+        .chars()
+        .zip([7, 3, 1].iter().cycle())
+        .map(|(c, w)| value(c) * w)
+        .sum();
+    sum % 10 == check
+}
+
+fn de_id_card(text: &str, findings: &mut Findings) {
+    for m in DE_ID.find_iter(text) {
+        let s = m.as_str();
+        if icao_check(&s[..9], num(&s[9..])) {
+            findings.insert(s);
+        }
+    }
+}
+
+// --- France ---------------------------------------------------------------
+
+/// Sex, year, month, department (with Corsica's 2A and 2B), commune, order,
+/// then the two-digit key, spaces allowed between groups.
+static FR_NIR: LazyLock<Regex> = LazyLock::new(|| {
+    re(r"\b([1-478]) ?(\d{2}) ?(\d{2}) ?(\d{2}|2[AB]) ?(\d{3}) ?(\d{3}) ?(\d{2})\b")
+});
+
+fn fr_nir(text: &str, findings: &mut Findings) {
+    for c in FR_NIR.captures_iter(text) {
+        let month = num(&c[3]);
+        if !(matches!(month, 1..=12 | 20..=42 | 50..=99)) {
+            continue;
+        }
+        let department = match &c[4] {
+            "2A" => "19",
+            "2B" => "18",
+            d => d,
+        };
+        let body = format!(
+            "{}{}{}{}{}{}",
+            &c[1], &c[2], &c[3], department, &c[5], &c[6]
+        );
+        let Ok(value) = body.parse::<u64>() else {
+            continue;
+        };
+        if 97 - value % 97 == u64::from(num(&c[7])) {
+            findings.insert(format!(
+                "{}{}{}{}{}{}{}",
+                &c[1], &c[2], &c[3], &c[4], &c[5], &c[6], &c[7]
+            ));
+        }
+    }
+}
+
+// --- Spain ----------------------------------------------------------------
+
+static ES_ID: LazyLock<Regex> = LazyLock::new(|| re(r"(?i)\b([XYZ]?)[ -]?(\d{7,8})[ -]?([A-Z])\b"));
+
+const DNI_LETTERS: &[u8] = b"TRWAGMYFPDXBNJZSQVHLCKE";
+
+fn es_dni_nie(text: &str, findings: &mut Findings) {
+    for c in ES_ID.captures_iter(text) {
+        let prefix = c[1].to_ascii_uppercase();
+        let digits = &c[2];
+        // DNI: eight digits; NIE: X, Y or Z and seven digits
+        let number = match (prefix.as_str(), digits.len()) {
+            ("", 8) => digits.to_string(),
+            ("X", 7) => format!("0{digits}"),
+            ("Y", 7) => format!("1{digits}"),
+            ("Z", 7) => format!("2{digits}"),
+            _ => continue,
+        };
+        let letter = c[3].to_ascii_uppercase();
+        if DNI_LETTERS[(num(&number) % 23) as usize] == letter.as_bytes()[0] {
+            findings.insert(format!("{prefix}{digits}{letter}"));
+        }
+    }
+}
+
+// --- Italy ----------------------------------------------------------------
+
+/// Surname and name letters, year, month letter, day, place code, check
+/// letter; digits may be replaced by letters (omocodia).
+static IT_CF: LazyLock<Regex> = LazyLock::new(|| {
+    let d = "[0-9LMNPQRSTUV]";
+    re(&format!(
+        r"(?i)\b[A-Z]{{6}}{d}{{2}}[ABCDEHLMPRST]{d}{{2}}[A-Z]{d}{{3}}[A-Z]\b"
+    ))
+});
+
+/// The Ministry's odd-position values for 0–9 and A–Z.
+const CF_ODD: [u32; 36] = [
+    1, 0, 5, 7, 9, 13, 15, 17, 19, 21, // 0-9
+    1, 0, 5, 7, 9, 13, 15, 17, 19, 21, 2, 4, 18, 20, 11, 3, 6, 8, 12, 14, 16, 10, 22, 25, 24,
+    23, // A-Z
+];
+
+pub fn codice_fiscale_valid(cf: &str) -> bool {
+    let index = |c: u8| {
+        if c.is_ascii_digit() {
+            (c - b'0') as usize
+        } else {
+            (c - b'A') as usize + 10
+        }
+    };
+    let even = |c: u8| {
+        if c.is_ascii_digit() {
+            u32::from(c - b'0')
+        } else {
+            u32::from(c - b'A')
+        }
+    };
+    let bytes = cf.as_bytes();
+    let sum: u32 = bytes[..15]
+        .iter()
+        .enumerate()
+        .map(|(i, &c)| {
+            if i % 2 == 0 {
+                CF_ODD[index(c)]
+            } else {
+                even(c)
+            }
+        })
+        .sum();
+    u32::from(bytes[15] - b'A') == sum % 26
+}
+
+fn it_codice_fiscale(text: &str, findings: &mut Findings) {
+    for m in IT_CF.find_iter(text) {
+        let cf = m.as_str().to_ascii_uppercase();
+        if codice_fiscale_valid(&cf) {
+            findings.insert(cf);
+        }
+    }
+}
+
+// --- Netherlands ----------------------------------------------------------
+
+/// Nine digits, sometimes written `1112.22.333`.
+static NL_BSN: LazyLock<Regex> = LazyLock::new(|| re(r"\b(\d{4})(\.?)(\d{2})(\.?)(\d{3})\b"));
+
+/// The eleven test: weights 9 down to 2, and −1 for the last digit.
+pub fn bsn_valid(n: &str) -> bool {
+    let d = digit_values(n);
+    let sum: i64 = d[..8]
+        .iter()
+        .zip((2..=9).rev())
+        .map(|(a, w)| i64::from(a * w))
+        .sum::<i64>()
+        - i64::from(d[8]);
+    sum != 0 && sum % 11 == 0
+}
+
+const BSN_WORDS: &[&str] = &[
+    "bsn",
+    "burgerservicenummer",
+    "sofinummer",
+    "sofi-nummer",
+    "citizen service number",
+];
+
+fn nl_bsn(text: &str, findings: &mut Findings) {
+    for c in NL_BSN.captures_iter(text) {
+        let whole = c.get(0).unwrap();
+        let n = format!("{}{}{}", &c[1], &c[3], &c[5]);
+        let written = &c[2] == "." && &c[4] == ".";
+        if bsn_valid(&n) && (written || word_near(text, whole.start(), whole.end(), BSN_WORDS)) {
+            findings.insert(n);
+        }
+    }
+}
+
+// --- Belgium --------------------------------------------------------------
+
+/// `YY.MM.DD-XXX.CC` or eleven digits.
+static BE_NN: LazyLock<Regex> =
+    LazyLock::new(|| re(r"\b(\d{2})\.?(\d{2})\.?(\d{2})-?(\d{3})\.?(\d{2})\b"));
+
+fn be_national_number(text: &str, findings: &mut Findings) {
+    for c in BE_NN.captures_iter(text) {
+        let (month, day) = (num(&c[2]), num(&c[3]));
+        // Month 0 and day 0 mean unknown; bis numbers add 20 or 40 to the month
+        if !(month <= 12 || (20..=32).contains(&month) || (40..=52).contains(&month)) || day > 31 {
+            continue;
+        }
+        let body = format!("{}{}{}{}", &c[1], &c[2], &c[3], &c[4]);
+        let check = u64::from(num(&c[5]));
+        let before_2000 = 97 - body.parse::<u64>().unwrap_or(0) % 97;
+        let since_2000 = 97 - format!("2{body}").parse::<u64>().unwrap_or(0) % 97;
+        if check == before_2000 || check == since_2000 {
+            findings.insert(format!("{body}{}", &c[5]));
+        }
+    }
+}
+
+// --- Poland ---------------------------------------------------------------
+
+static ELEVEN: LazyLock<Regex> = LazyLock::new(|| re(r"\b\d{11}\b"));
+
+/// Weights 1, 3, 7, 9 repeating; the birth date encodes the century in the
+/// month (+80 for the 1800s, +20 for the 2000s, and so on).
+pub fn pesel_valid(n: &str) -> bool {
+    let d = digit_values(n);
+    let sum: u32 = d[..10]
+        .iter()
+        .zip([1, 3, 7, 9].iter().cycle())
+        .map(|(a, w)| a * w)
+        .sum();
+    let month = d[2] * 10 + d[3];
+    let (century, month) = match month {
+        81..=92 => (1800, month - 80),
+        1..=12 => (1900, month),
+        21..=32 => (2000, month - 20),
+        41..=52 => (2100, month - 40),
+        _ => return false,
+    };
+    let year = century + d[0] * 10 + d[1];
+    (10 - sum % 10) % 10 == d[10] && (1..=super::days_in(year, month)).contains(&(d[4] * 10 + d[5]))
+}
+
+const PESEL_WORDS: &[&str] = &["pesel", "numer pesel", "nr pesel"];
+
+fn pl_pesel(text: &str, findings: &mut Findings) {
+    for m in ELEVEN.find_iter(text) {
+        if pesel_valid(m.as_str()) && word_near(text, m.start(), m.end(), PESEL_WORDS) {
+            findings.insert(m.as_str());
+        }
+    }
+}
+
+// --- Sweden ---------------------------------------------------------------
+
+/// `YYMMDD-NNNN`, `YYYYMMDD-NNNN` (`+` after 100), or the bare digits.
+static SE_PNR: LazyLock<Regex> =
+    LazyLock::new(|| re(r"\b(?:\d{2})?(\d{2})(\d{2})(\d{2})([-+]?)(\d{4})\b"));
+
+const SE_WORDS: &[&str] = &[
+    "personnummer",
+    "personnr",
+    "person nr",
+    "samordningsnummer",
+    "pnr",
+];
+
+fn se_personnummer(text: &str, findings: &mut Findings) {
+    for c in SE_PNR.captures_iter(text) {
+        let whole = c.get(0).unwrap();
+        let (yy, month, day) = (num(&c[1]), num(&c[2]), num(&c[3]));
+        // Coordination numbers add 60 to the day
+        let day = if day > 60 { day - 60 } else { day };
+        let ten = format!("{}{}{}{}", &c[1], &c[2], &c[3], &c[5]);
+        let written = !c[4].is_empty();
+        if valid_short_date(yy, month, day)
+            && checks::luhn(&ten)
+            && (written || word_near(text, whole.start(), whole.end(), SE_WORDS))
+        {
+            findings.insert(ten);
+        }
+    }
+}
+
+// --- Denmark --------------------------------------------------------------
+
+static DK_CPR: LazyLock<Regex> = LazyLock::new(|| re(r"\b(\d{2})(\d{2})(\d{2})-?(\d{4})\b"));
+
+const CPR_WORDS: &[&str] = &["cpr", "cpr-nr", "cpr nr", "cpr-nummer", "personnummer"];
+
+fn dk_cpr(text: &str, findings: &mut Findings) {
+    for c in DK_CPR.captures_iter(text) {
+        let whole = c.get(0).unwrap();
+        if valid_short_date(num(&c[3]), num(&c[2]), num(&c[1]))
+            && word_near(text, whole.start(), whole.end(), CPR_WORDS)
+        {
+            findings.insert(whole.as_str().replace('-', ""));
+        }
+    }
+}
+
+// --- Finland --------------------------------------------------------------
+
+static FI_HETU: LazyLock<Regex> =
+    LazyLock::new(|| re(r"(?i)\b(\d{2})(\d{2})(\d{2})[-+ABCDEFYXWVU](\d{3})([0-9A-Y])\b"));
+
+const HETU_CHECK: &[u8] = b"0123456789ABCDEFHJKLMNPRSTUVWXY";
+
+fn fi_hetu(text: &str, findings: &mut Findings) {
+    for c in FI_HETU.captures_iter(text) {
+        let (day, month, yy) = (num(&c[1]), num(&c[2]), num(&c[3]));
+        let n: u64 = format!("{}{}{}{}", &c[1], &c[2], &c[3], &c[4])
+            .parse()
+            .unwrap_or(0);
+        let check = c[5].to_ascii_uppercase().as_bytes()[0];
+        if valid_short_date(yy, month, day) && HETU_CHECK[(n % 31) as usize] == check {
+            findings.insert(c[0].to_ascii_uppercase());
+        }
+    }
+}
+
+// --- Ireland --------------------------------------------------------------
+
+static IE_PPS: LazyLock<Regex> = LazyLock::new(|| re(r"(?i)\b(\d{7})([A-W])([ABHW]?)\b"));
+
+const PPS_CHECK: &[u8] = b"WABCDEFGHIJKLMNOPQRSTUV";
+
+fn ie_pps(text: &str, findings: &mut Findings) {
+    for c in IE_PPS.captures_iter(text) {
+        let mut sum: u32 = digit_values(&c[1])
+            .iter()
+            .zip((2..=8).rev())
+            .map(|(a, w)| a * w)
+            .sum();
+        // The second letter counts, times 9; W (the old form) counts as 0
+        let second = c[3].to_ascii_uppercase();
+        if let Some(&letter) = second.as_bytes().first()
+            && letter != b'W'
+        {
+            sum += u32::from(letter - b'A' + 1) * 9;
+        }
+        let check = c[2].to_ascii_uppercase().as_bytes()[0];
+        if PPS_CHECK[(sum % 23) as usize] == check {
+            findings.insert(c[0].to_ascii_uppercase());
+        }
+    }
+}
+
+// --- Portugal -------------------------------------------------------------
+
+static NINE: LazyLock<Regex> = LazyLock::new(|| re(r"\b\d{9}\b"));
+
+/// Mod 11 over weights 9 down to 2; a check of 10 or 11 becomes 0.
+pub fn nif_valid(n: &str) -> bool {
+    let d = digit_values(n);
+    let sum: u32 = d[..8].iter().zip((2..=9).rev()).map(|(a, w)| a * w).sum();
+    let check = match 11 - sum % 11 {
+        10 | 11 => 0,
+        c => c,
+    };
+    matches!(d[0], 1 | 2 | 3 | 5 | 6 | 8 | 9) && check == d[8]
+}
+
+const NIF_WORDS: &[&str] = &[
+    "nif",
+    "contribuinte",
+    "número de identificação fiscal",
+    "numero de contribuinte",
+];
+
+fn pt_nif(text: &str, findings: &mut Findings) {
+    for m in NINE.find_iter(text) {
+        if nif_valid(m.as_str()) && word_near(text, m.start(), m.end(), NIF_WORDS) {
+            findings.insert(m.as_str());
+        }
+    }
+}
+
+// --- Austria --------------------------------------------------------------
+
+/// A serial and check digit, then the birth date: `1237 010180`.
+static AT_SVNR: LazyLock<Regex> = LazyLock::new(|| re(r"\b(\d{3})(\d)( ?)(\d{2})(\d{2})(\d{2})\b"));
+
+const SVNR_WORDS: &[&str] = &[
+    "sozialversicherungsnummer",
+    "svnr",
+    "sv-nr",
+    "sv-nummer",
+    "versicherungsnummer",
+];
+
+fn at_svnr(text: &str, findings: &mut Findings) {
+    for c in AT_SVNR.captures_iter(text) {
+        let whole = c.get(0).unwrap();
+        let n = format!("{}{}{}{}{}", &c[1], &c[2], &c[4], &c[5], &c[6]);
+        let d = digit_values(&n);
+        let sum: u32 = d
+            .iter()
+            .zip([3, 7, 9, 0, 5, 8, 4, 2, 1, 6])
+            .map(|(a, w)| a * w)
+            .sum();
+        let written = &c[3] == " ";
+        if d[0] != 0
+            && sum % 11 == d[3]
+            && valid_short_date(num(&c[6]), num(&c[5]), num(&c[4]))
+            && (written || word_near(text, whole.start(), whole.end(), SVNR_WORDS))
+            && stands_alone(text, whole.start(), whole.end())
+        {
+            findings.insert(n);
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::mailflow::detectors::by_id;
+
+    fn count(id: &str, text: &str) -> usize {
+        by_id(id).unwrap().count(text)
+    }
+
+    #[test]
+    fn germany() {
+        assert_eq!(count("de-tax-id", "86 095 742 719"), 1);
+        assert_eq!(count("de-tax-id", "Steuer-ID: 86095742719"), 1);
+        assert_eq!(count("de-tax-id", "Rechnung 86095742719"), 0);
+        assert_eq!(count("de-tax-id", "86 095 742 718"), 0);
+        // ICAO 9303's German specimen card
+        assert_eq!(count("de-id-card", "Ausweis T220001293"), 1);
+        assert_eq!(count("de-id-card", "T220001294"), 0);
+    }
+
+    #[test]
+    fn france_spain_italy() {
+        assert_eq!(count("fr-nir", "2 55 08 14 168 025 38"), 1);
+        assert_eq!(count("fr-nir", "255081416802539"), 0);
+        assert_eq!(count("es-dni-nie", "DNI 12345678Z, NIE X-1234567-L"), 2);
+        assert_eq!(count("es-dni-nie", "12345678A"), 0);
+        assert_eq!(count("it-codice-fiscale", "CF: RSSMRA85T10A562S"), 1);
+        assert_eq!(count("it-codice-fiscale", "RSSMRA85T10A562T"), 0);
+    }
+
+    #[test]
+    fn benelux() {
+        assert_eq!(count("nl-bsn", "1112.22.333"), 1);
+        assert_eq!(count("nl-bsn", "BSN 111222333"), 1);
+        assert_eq!(count("nl-bsn", "order 111222333"), 0);
+        assert_eq!(count("nl-bsn", "BSN 111222334"), 0);
+        assert_eq!(count("be-national-number", "85.07.30-033.28"), 1);
+        assert_eq!(count("be-national-number", "85073003329"), 0);
+    }
+
+    #[test]
+    fn nordics() {
+        assert_eq!(count("se-personnummer", "811218-9876"), 1);
+        assert_eq!(count("se-personnummer", "811218-9875"), 0);
+        assert_eq!(count("se-personnummer", "order 8112189876"), 0);
+        assert_eq!(count("se-personnummer", "personnummer 198112189876"), 1);
+        assert_eq!(count("dk-cpr", "CPR-nr: 010170-1234"), 1);
+        assert_eq!(count("dk-cpr", "010170-1234"), 0);
+        assert_eq!(count("dk-cpr", "CPR 320170-1234"), 0);
+        assert_eq!(count("fi-hetu", "131052-308T"), 1);
+        assert_eq!(count("fi-hetu", "131052-308U"), 0);
+    }
+
+    #[test]
+    fn poland_ireland_portugal_austria() {
+        assert_eq!(count("pl-pesel", "PESEL 44051401359, pesel 02070803628"), 2);
+        assert_eq!(count("pl-pesel", "PESEL 44051401358"), 0);
+        assert_eq!(count("pl-pesel", "44051401359"), 0);
+        assert_eq!(count("ie-pps", "PPS 1234567T and 1234567FA"), 2);
+        assert_eq!(count("ie-pps", "1234567U"), 0);
+        assert_eq!(count("pt-nif", "NIF 123456789"), 1);
+        assert_eq!(count("pt-nif", "NIF 123456788"), 0);
+        assert_eq!(count("at-svnr", "1237 010180"), 1);
+        assert_eq!(count("at-svnr", "SVNR 1237010180"), 1);
+        assert_eq!(count("at-svnr", "1238 010180"), 0);
+    }
+}

crates/features/src/mailflow/detectors/europe.rs

@@ -0,0 +1,116 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Coffey Labs
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+//! European identifiers outside the EU (§2.3): Norway's national identity
+//! number and Switzerland's AHV number.
+
+use super::{Detector, Findings, Region, Strength, digit_values, valid_short_date};
+use regex::Regex;
+use std::sync::LazyLock;
+
+pub static DETECTORS: &[Detector] = &[
+    Detector::new(
+        "no-fnr",
+        "Norway: national identity number",
+        Region::Europe,
+        Strength::Checked,
+        no_fnr,
+    ),
+    Detector::new(
+        "ch-ahv",
+        "Switzerland: AHV number",
+        Region::Europe,
+        Strength::Checked,
+        ch_ahv,
+    ),
+];
+
+static ELEVEN: LazyLock<Regex> =
+    LazyLock::new(|| Regex::new(r"\b\d{6} ?\d{5}\b").expect("detector pattern"));
+
+/// Two mod 11 check digits over a birth date (D-numbers add 40 to the day,
+/// H-numbers 40 to the month): strong enough to count alone.
+pub fn fnr_valid(n: &str) -> bool {
+    let d = digit_values(n);
+    if d.len() != 11 {
+        return false;
+    }
+    let check =
+        |weights: &[u32]| match 11 - d.iter().zip(weights).map(|(a, w)| a * w).sum::<u32>() % 11 {
+            11 => Some(0),
+            10 => None,
+            c => Some(c),
+        };
+    let day = d[0] * 10 + d[1];
+    let month = d[2] * 10 + d[3];
+    let day = if day > 40 { day - 40 } else { day };
+    let month = if month > 40 { month - 40 } else { month };
+    valid_short_date(d[4] * 10 + d[5], month, day)
+        && check(&[3, 7, 6, 1, 8, 9, 4, 5, 2]) == Some(d[9])
+        && check(&[5, 4, 3, 2, 7, 6, 5, 4, 3, 2]) == Some(d[10])
+}
+
+fn no_fnr(text: &str, findings: &mut Findings) {
+    for m in ELEVEN.find_iter(text) {
+        let n = m.as_str().replace(' ', "");
+        if fnr_valid(&n) {
+            findings.insert(n);
+        }
+    }
+}
+
+/// `756.1234.5678.97`: the country prefix, then an EAN-13 check digit.
+static AHV: LazyLock<Regex> = LazyLock::new(|| {
+    Regex::new(r"\b756[. ]?\d{4}[. ]?\d{4}[. ]?\d{2}\b").expect("detector pattern")
+});
+
+pub fn ean13_valid(n: &str) -> bool {
+    let d = digit_values(n);
+    if d.len() != 13 {
+        return false;
+    }
+    let sum: u32 = d[..12]
+        .iter()
+        .enumerate()
+        .map(|(i, x)| if i % 2 == 0 { *x } else { x * 3 })
+        .sum();
+    (10 - sum % 10) % 10 == d[12]
+}
+
+fn ch_ahv(text: &str, findings: &mut Findings) {
+    for m in AHV.find_iter(text) {
+        let n: String = m.as_str().chars().filter(char::is_ascii_digit).collect();
+        if ean13_valid(&n) {
+            findings.insert(n);
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::mailflow::detectors::by_id;
+
+    fn count(id: &str, text: &str) -> usize {
+        by_id(id).unwrap().count(text)
+    }
+
+    #[test]
+    fn norway() {
+        assert_eq!(count("no-fnr", "01019000083"), 1);
+        assert_eq!(count("no-fnr", "010190 00083"), 1);
+        assert_eq!(count("no-fnr", "01019000084"), 0);
+        // Not a date
+        assert_eq!(count("no-fnr", "32019000083"), 0);
+    }
+
+    #[test]
+    fn switzerland() {
+        // The federal example
+        assert_eq!(count("ch-ahv", "AHV 756.9217.0769.85"), 1);
+        assert_eq!(count("ch-ahv", "7569217076985"), 1);
+        assert_eq!(count("ch-ahv", "756.9217.0769.86"), 0);
+    }
+}

crates/features/src/mailflow/detectors/mod.rs

@@ -19,8 +19,18 @@
 //! same card number pasted twice counts once. They stay in memory: callers
 //! read only [`Findings::len`].
 
+pub mod africa;
+pub mod americas;
 pub mod any;
+pub mod asia;
+pub mod australia;
+pub mod canada;
 pub mod checks;
+pub mod eu;
+pub mod europe;
+pub mod templates;
+pub mod uk;
+pub mod us;
 
 use ahash::AHashSet;
 
@@ -108,7 +118,20 @@ impl Detector {
 
 /// Every detector, in the order the console lists them.
 pub fn all() -> impl Iterator<Item = &'static Detector> {
-    any::DETECTORS.iter()
+    [
+        any::DETECTORS,
+        us::DETECTORS,
+        uk::DETECTORS,
+        canada::DETECTORS,
+        australia::DETECTORS,
+        eu::DETECTORS,
+        europe::DETECTORS,
+        asia::DETECTORS,
+        americas::DETECTORS,
+        africa::DETECTORS,
+    ]
+    .into_iter()
+    .flatten()
 }
 
 pub fn by_id(id: &str) -> Option<&'static Detector> {
@@ -159,6 +182,38 @@ pub fn stands_alone(text: &str, start: usize, end: usize) -> bool {
     before.is_none_or(|c| !c.is_alphanumeric()) && after.is_none_or(|c| !c.is_alphanumeric())
 }
 
+/// Days in `month` of `year` (0 for a month that doesn't exist).
+pub fn days_in(year: u32, month: u32) -> u32 {
+    match month {
+        1 | 3 | 5 | 7 | 8 | 10 | 12 => 31,
+        4 | 6 | 9 | 11 => 30,
+        2 if year.is_multiple_of(4) && (!year.is_multiple_of(100) || year.is_multiple_of(400)) => {
+            29
+        }
+        2 => 28,
+        _ => 0,
+    }
+}
+
+/// Whether `year`-`month`-`day` is a real date between 1900 and 2100.
+pub fn valid_date(year: u32, month: u32, day: u32) -> bool {
+    (1900..=2100).contains(&year) && (1..=days_in(year, month)).contains(&day)
+}
+
+/// Whether a two-digit year, month and day make a real date in either the
+/// 1900s or the 2000s.
+pub fn valid_short_date(yy: u32, month: u32, day: u32) -> bool {
+    valid_date(1900 + yy, month, day) || valid_date(2000 + yy, month, day)
+}
+
+/// The value of each digit in `s`.
+pub fn digit_values(s: &str) -> Vec<u32> {
+    s.bytes()
+        .filter(u8::is_ascii_digit)
+        .map(|b| u32::from(b - b'0'))
+        .collect()
+}
+
 /// The ASCII digits of `s`.
 pub fn digits(s: &str) -> String {
     s.chars().filter(char::is_ascii_digit).collect()
@@ -188,6 +243,30 @@ mod tests {
         assert!(word_near(&text, start, start + 8, &["passport"]));
     }
 
+    /// An ordinary business email: order, invoice and tracking numbers,
+    /// dates, amounts, a street address. Nothing here is an identifier, so
+    /// no detector may fire, except the contact ones on the signature.
+    #[test]
+    fn ordinary_mail_finds_nothing() {
+        let text = "Hi Dana,\n\nThanks for order 4471-2290 placed 2026-09-14. Invoice INV-2026-00917 \
+            for $12,480.00 is due 10/31/2026; PO 7731902 covers lines 1-14. Tracking \
+            1Z999AA10123456784, parcel 3 of 5, 12.5 kg, box 40x30x20 cm. Meeting moved to \
+            Tuesday 9:30-10:15 in room 2B, building 1177. Ticket #5520318, case 20260914-0042. \
+            Version 2026.9.28.4, build 118822, commit 5a73a118. Serial SN-88213-X. \
+            Ship to 1600 Amphitheatre Pkwy, Mountain View, CA 94043. Revenue grew 18% to \
+            1,204,332 units; see figures 3.1-3.4 and table 12.\n\nBest,\nSam\n\
+            Sam Rivera | +1 (415) 555-2671 | [email protected]";
+        let quiet = ["email-addresses", "phone-numbers"];
+        for detector in all().filter(|d| !quiet.contains(&d.id)) {
+            assert_eq!(
+                detector.count(text),
+                0,
+                "{} fired on ordinary mail",
+                detector.id
+            );
+        }
+    }
+
     #[test]
     fn ids_are_unique() {
         let mut seen = AHashSet::new();

crates/features/src/mailflow/detectors/templates.rs

@@ -0,0 +1,97 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Coffey Labs
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+//! Templates (§2.3): named sets of detectors, so a policy doesn't pick forty
+//! one at a time. Each is named for what it finds, never for a law, and is a
+//! starting point: once added to a rule, its detectors can be changed.
+
+pub struct Template {
+    pub id: &'static str,
+    pub name: &'static str,
+    pub detectors: &'static [&'static str],
+}
+
+pub static TEMPLATES: &[Template] = &[
+    Template {
+        id: "payment-and-bank",
+        name: "Payment cards and bank accounts",
+        detectors: &["payment-card", "iban", "swift-bic", "us-aba-routing"],
+    },
+    Template {
+        id: "us-personal",
+        name: "US personal identifiers",
+        detectors: &[
+            "us-ssn",
+            "us-itin",
+            "us-ein",
+            "us-drivers-license",
+            "passport",
+            "date-of-birth",
+        ],
+    },
+    Template {
+        id: "uk-personal",
+        name: "UK personal identifiers",
+        detectors: &["uk-nino", "uk-utr", "uk-nhs", "passport", "date-of-birth"],
+    },
+    Template {
+        id: "eu-national",
+        name: "EU national identifiers",
+        detectors: &[
+            "de-tax-id",
+            "de-id-card",
+            "fr-nir",
+            "es-dni-nie",
+            "it-codice-fiscale",
+            "nl-bsn",
+            "be-national-number",
+            "pl-pesel",
+            "se-personnummer",
+            "dk-cpr",
+            "fi-hetu",
+            "ie-pps",
+            "pt-nif",
+            "at-svnr",
+        ],
+    },
+    Template {
+        id: "health",
+        name: "Health identifiers",
+        detectors: &["uk-nhs", "us-mbi", "us-npi", "us-dea", "au-medicare"],
+    },
+    Template {
+        id: "credentials",
+        name: "Credentials and keys",
+        detectors: &["private-key", "credentials"],
+    },
+    Template {
+        id: "contact-lists",
+        name: "Contact lists",
+        detectors: &["email-addresses", "phone-numbers"],
+    },
+];
+
+pub fn by_id(id: &str) -> Option<&'static Template> {
+    TEMPLATES.iter().find(|template| template.id == id)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn every_template_names_real_detectors() {
+        for template in TEMPLATES {
+            for id in template.detectors {
+                assert!(
+                    super::super::by_id(id).is_some(),
+                    "{}: no detector {id}",
+                    template.id
+                );
+            }
+        }
+    }
+}

crates/features/src/mailflow/detectors/uk.rs

@@ -0,0 +1,155 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Coffey Labs
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+//! United Kingdom identifiers (§2.3): HMRC's National Insurance number and
+//! Unique Taxpayer Reference, and the NHS number.
+
+use super::{Detector, Findings, Region, Strength, word_near};
+use regex::Regex;
+use std::sync::LazyLock;
+
+pub static DETECTORS: &[Detector] = &[
+    Detector::new(
+        "uk-nino",
+        "UK National Insurance number",
+        Region::Uk,
+        Strength::Checked,
+        nino,
+    ),
+    Detector::new(
+        "uk-nhs",
+        "UK NHS number",
+        Region::Uk,
+        Strength::Checked,
+        nhs,
+    ),
+    Detector::new(
+        "uk-utr",
+        "UK Unique Taxpayer Reference",
+        Region::Uk,
+        Strength::NeedsWord,
+        utr,
+    ),
+];
+
+fn re(pattern: &str) -> Regex {
+    Regex::new(pattern).expect("detector pattern")
+}
+
+/// Two letters, six digits (often in pairs), a suffix A–D.
+static NINO: LazyLock<Regex> =
+    LazyLock::new(|| re(r"(?i)\b([A-Z])([A-Z]) ?(\d{2}) ?(\d{2}) ?(\d{2}) ?([A-D])\b"));
+
+/// HMRC's rules: D, F, I, Q, U and V are never used; O never second; and
+/// BG, GB, KN, NK, NT, TN and ZZ are never allocated.
+fn nino_prefix(first: char, second: char) -> bool {
+    const NEVER: &str = "DFIQUV";
+    let pair: String = [first, second].iter().collect();
+    !NEVER.contains(first)
+        && !NEVER.contains(second)
+        && second != 'O'
+        && !["BG", "GB", "KN", "NK", "NT", "TN", "ZZ"].contains(&pair.as_str())
+}
+
+fn nino(text: &str, findings: &mut Findings) {
+    for c in NINO.captures_iter(text) {
+        let first = c[1].to_ascii_uppercase().chars().next().unwrap();
+        let second = c[2].to_ascii_uppercase().chars().next().unwrap();
+        if nino_prefix(first, second) {
+            findings.insert(format!(
+                "{first}{second}{}{}{}{}",
+                &c[3],
+                &c[4],
+                &c[5],
+                c[6].to_ascii_uppercase()
+            ));
+        }
+    }
+}
+
+/// `NNN NNN NNNN` stands alone; ten bare digits need a word.
+static NHS: LazyLock<Regex> = LazyLock::new(|| re(r"\b(\d{3})([ -]?)(\d{3})([ -]?)(\d{4})\b"));
+
+/// Mod 11: weights 10 down to 2 over the first nine digits; the check digit
+/// is 11 minus the remainder (11 becomes 0; 10 is never issued).
+pub fn nhs_valid(n: &str) -> bool {
+    let d: Vec<u32> = n.bytes().map(|b| u32::from(b - b'0')).collect();
+    let sum: u32 = d[..9].iter().zip((2..=10).rev()).map(|(a, w)| a * w).sum();
+    match 11 - sum % 11 {
+        11 => d[9] == 0,
+        10 => false,
+        check => d[9] == check,
+    }
+}
+
+const NHS_WORDS: &[&str] = &["nhs", "nhs number", "nhs no"];
+
+fn nhs(text: &str, findings: &mut Findings) {
+    for c in NHS.captures_iter(text) {
+        let whole = c.get(0).unwrap();
+        let n = format!("{}{}{}", &c[1], &c[3], &c[5]);
+        let written = !c[2].is_empty() && c[2] == c[4];
+        if nhs_valid(&n) && (written || word_near(text, whole.start(), whole.end(), NHS_WORDS)) {
+            findings.insert(n);
+        }
+    }
+}
+
+static UTR: LazyLock<Regex> = LazyLock::new(|| re(r"\b\d{5} ?\d{5}\b"));
+
+const UTR_WORDS: &[&str] = &[
+    "utr",
+    "unique taxpayer reference",
+    "tax reference",
+    "self assessment",
+];
+
+fn utr(text: &str, findings: &mut Findings) {
+    for m in UTR.find_iter(text) {
+        if word_near(text, m.start(), m.end(), UTR_WORDS) {
+            findings.insert(m.as_str().replace(' ', ""));
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::mailflow::detectors::by_id;
+
+    fn count(id: &str, text: &str) -> usize {
+        by_id(id).unwrap().count(text)
+    }
+
+    #[test]
+    fn national_insurance() {
+        assert_eq!(count("uk-nino", "NI: AB 12 34 56 C, ce123456d"), 2);
+        // Letters never used, pairs never allocated, a suffix past D
+        for bad in [
+            "QQ123456C",
+            "AO123456C",
+            "GB123456A",
+            "AB123456E",
+            "DA123456A",
+        ] {
+            assert_eq!(count("uk-nino", bad), 0, "{bad}");
+        }
+    }
+
+    #[test]
+    fn nhs_numbers() {
+        // The NHS's own example
+        assert_eq!(count("uk-nhs", "943 476 5919"), 1);
+        assert_eq!(count("uk-nhs", "943 476 5918"), 0);
+        assert_eq!(count("uk-nhs", "order 9434765919"), 0);
+        assert_eq!(count("uk-nhs", "NHS number 9434765919"), 1);
+    }
+
+    #[test]
+    fn utr() {
+        assert_eq!(count("uk-utr", "UTR 12345 67890"), 1);
+        assert_eq!(count("uk-utr", "order 1234567890"), 0);
+    }
+}

crates/features/src/mailflow/detectors/us.rs

@@ -0,0 +1,304 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Coffey Labs
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+//! United States identifiers (§2.3), each from its issuer's published rules:
+//! the SSA (SSN), the IRS (ITIN, EIN), the ABA (routing numbers), CMS (MBI,
+//! NPI) and the DEA.
+
+use super::{Detector, Findings, Region, Strength, checks, digits, stands_alone, word_near};
+use regex::Regex;
+use std::sync::LazyLock;
+
+pub static DETECTORS: &[Detector] = &[
+    Detector::new(
+        "us-ssn",
+        "US Social Security number",
+        Region::Us,
+        Strength::Checked,
+        ssn,
+    ),
+    Detector::new("us-itin", "US ITIN", Region::Us, Strength::Checked, itin),
+    Detector::new("us-ein", "US EIN", Region::Us, Strength::NeedsWord, ein),
+    Detector::new(
+        "us-aba-routing",
+        "US bank routing number",
+        Region::Us,
+        Strength::NeedsWord,
+        aba_routing,
+    ),
+    Detector::new(
+        "us-drivers-license",
+        "US driver's license",
+        Region::Us,
+        Strength::NeedsWord,
+        drivers_license,
+    ),
+    Detector::new(
+        "us-mbi",
+        "US Medicare Beneficiary Identifier",
+        Region::Us,
+        Strength::Checked,
+        mbi,
+    ),
+    Detector::new(
+        "us-npi",
+        "US National Provider Identifier",
+        Region::Us,
+        Strength::NeedsWord,
+        npi,
+    ),
+    Detector::new(
+        "us-dea",
+        "US DEA registration number",
+        Region::Us,
+        Strength::Checked,
+        dea,
+    ),
+];
+
+fn re(pattern: &str) -> Regex {
+    Regex::new(pattern).expect("detector pattern")
+}
+
+/// `AAA-GG-SSSS` (dashes or spaces), or nine bare digits.
+static NINE: LazyLock<Regex> = LazyLock::new(|| re(r"\b(\d{3})([ -]?)(\d{2})([ -]?)(\d{4})\b"));
+
+/// Numbers the SSA has published as never valid: widely printed examples.
+const SSN_EXAMPLES: &[&str] = &["078051120", "219099999"];
+
+fn ssn_rules(area: u32, group: u32, serial: u32) -> bool {
+    area != 0 && area != 666 && area < 900 && group != 0 && serial != 0
+}
+
+const SSN_WORDS: &[&str] = &["ssn", "social security", "soc sec", "ss#", "ss no"];
+
+fn ssn(text: &str, findings: &mut Findings) {
+    for c in NINE.captures_iter(text) {
+        let whole = c.get(0).unwrap();
+        let (area, group, serial) = (num(&c[1]), num(&c[3]), num(&c[5]));
+        let number = format!("{}{}{}", &c[1], &c[3], &c[5]);
+        // Written form (with both separators, the same one) stands alone;
+        // nine bare digits need a word
+        let written = !c[2].is_empty() && c[2] == c[4];
+        if ssn_rules(area, group, serial)
+            && !SSN_EXAMPLES.contains(&number.as_str())
+            && (written || word_near(text, whole.start(), whole.end(), SSN_WORDS))
+        {
+            findings.insert(number);
+        }
+    }
+}
+
+/// ITINs: 9XX, then a group in the IRS's ranges.
+fn itin_group(group: u32) -> bool {
+    matches!(group, 50..=65 | 70..=88 | 90..=92 | 94..=99)
+}
+
+const ITIN_WORDS: &[&str] = &["itin", "taxpayer identification", "tax id"];
+
+fn itin(text: &str, findings: &mut Findings) {
+    for c in NINE.captures_iter(text) {
+        let whole = c.get(0).unwrap();
+        let written = !c[2].is_empty() && c[2] == c[4];
+        if c[1].starts_with('9')
+            && itin_group(num(&c[3]))
+            && (written || word_near(text, whole.start(), whole.end(), ITIN_WORDS))
+        {
+            findings.insert(format!("{}{}{}", &c[1], &c[3], &c[5]));
+        }
+    }
+}
+
+static EIN: LazyLock<Regex> = LazyLock::new(|| re(r"\b(\d{2})-?(\d{7})\b"));
+
+/// The prefixes the IRS assigns to its campuses and internet EINs.
+fn ein_prefix(prefix: u32) -> bool {
+    matches!(prefix, 1..=6 | 10..=16 | 20..=27 | 30..=48 | 50..=68 | 71..=77 | 80..=88 | 90..=95 | 98 | 99)
+}
+
+const EIN_WORDS: &[&str] = &[
+    "ein",
+    "fein",
+    "employer identification",
+    "tax id",
+    "tin",
+    "federal tax",
+];
+
+fn ein(text: &str, findings: &mut Findings) {
+    for c in EIN.captures_iter(text) {
+        let whole = c.get(0).unwrap();
+        if ein_prefix(num(&c[1])) && word_near(text, whole.start(), whole.end(), EIN_WORDS) {
+            findings.insert(format!("{}{}", &c[1], &c[2]));
+        }
+    }
+}
+
+static ROUTING: LazyLock<Regex> = LazyLock::new(|| re(r"\b\d{9}\b"));
+
+/// The ABA check: 3, 7 and 1 weights, mod 10; and a Federal Reserve prefix.
+pub fn aba_valid(n: &str) -> bool {
+    let d: Vec<u32> = n.bytes().map(|b| u32::from(b - b'0')).collect();
+    let prefix = d[0] * 10 + d[1];
+    matches!(prefix, 0..=12 | 21..=32 | 61..=72 | 80)
+        && (3 * (d[0] + d[3] + d[6]) + 7 * (d[1] + d[4] + d[7]) + (d[2] + d[5] + d[8]))
+            .is_multiple_of(10)
+}
+
+const ROUTING_WORDS: &[&str] = &["routing", "aba", "rtn", "routing number", "transit"];
+
+fn aba_routing(text: &str, findings: &mut Findings) {
+    for m in ROUTING.find_iter(text) {
+        // One random number in ten passes the check: always needs a word
+        if aba_valid(m.as_str()) && word_near(text, m.start(), m.end(), ROUTING_WORDS) {
+            findings.insert(m.as_str());
+        }
+    }
+}
+
+/// The shapes states issue: up to two letters, then 5–14 digits, dashes
+/// allowed (Florida and Illinois print them).
+static LICENSE: LazyLock<Regex> = LazyLock::new(|| re(r"\b[A-Z]{0,2}\d[\d-]{3,16}\d\b"));
+
+const LICENSE_WORDS: &[&str] = &[
+    "driver's license",
+    "drivers license",
+    "driver license",
+    "driver's licence",
+    "dl",
+    "dl#",
+    "license number",
+    "lic no",
+    "dmv",
+];
+
+fn drivers_license(text: &str, findings: &mut Findings) {
+    for m in LICENSE.find_iter(text) {
+        let n = digits(m.as_str());
+        if (5..=14).contains(&n.len()) && word_near(text, m.start(), m.end(), LICENSE_WORDS) {
+            findings.insert(m.as_str().replace('-', ""));
+        }
+    }
+}
+
+/// CMS's MBI: 11 characters in a fixed pattern of digits, letters and
+/// either, the letters S, L, O, I, B and Z never used; dashes may follow the
+/// 4th and 7th.
+static MBI: LazyLock<Regex> = LazyLock::new(|| {
+    let c = "[AC-HJKMNP-RT-Y]";
+    let an = "[AC-HJKMNP-RT-Y0-9]";
+    re(&format!(
+        r"\b[1-9]{c}{an}[0-9]-?{c}{an}[0-9]-?{c}{c}[0-9][0-9]\b"
+    ))
+});
+
+fn mbi(text: &str, findings: &mut Findings) {
+    for m in MBI.find_iter(text) {
+        findings.insert(m.as_str().replace('-', ""));
+    }
+}
+
+static TEN: LazyLock<Regex> = LazyLock::new(|| re(r"\b[12]\d{9}\b"));
+
+const NPI_WORDS: &[&str] = &["npi", "national provider", "provider id", "provider number"];
+
+/// NPI: Luhn over the ISO card-issuer prefix 80840 and the number.
+fn npi(text: &str, findings: &mut Findings) {
+    for m in TEN.find_iter(text) {
+        if checks::luhn(&format!("80840{}", m.as_str()))
+            && word_near(text, m.start(), m.end(), NPI_WORDS)
+        {
+            findings.insert(m.as_str());
+        }
+    }
+}
+
+static DEA: LazyLock<Regex> = LazyLock::new(|| re(r"\b([ABCDEFGHJKLMPRSTUX][A-Z9])(\d{7})\b"));
+
+/// DEA: (1st + 3rd + 5th) + 2 × (2nd + 4th + 6th) ends in the 7th digit.
+fn dea(text: &str, findings: &mut Findings) {
+    for c in DEA.captures_iter(text) {
+        let d: Vec<u32> = c[2].bytes().map(|b| u32::from(b - b'0')).collect();
+        if ((d[0] + d[2] + d[4]) + 2 * (d[1] + d[3] + d[5])) % 10 == d[6] {
+            let whole = c.get(0).unwrap();
+            if stands_alone(text, whole.start(), whole.end()) {
+                findings.insert(whole.as_str());
+            }
+        }
+    }
+}
+
+fn num(s: &str) -> u32 {
+    s.parse().unwrap_or(0)
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::mailflow::detectors::by_id;
+
+    fn count(id: &str, text: &str) -> usize {
+        by_id(id).unwrap().count(text)
+    }
+
+    #[test]
+    fn ssn() {
+        assert_eq!(count("us-ssn", "SSN 536-22-1234, also 536 22 1235"), 2);
+        // Bare digits: only with a word
+        assert_eq!(count("us-ssn", "ref 536221234"), 0);
+        assert_eq!(count("us-ssn", "social security: 536221234"), 1);
+        // Never issued, the SSA's printed examples, mixed separators
+        for bad in [
+            "000-12-3456",
+            "666-12-3456",
+            "912-12-3456",
+            "123-00-4567",
+            "123-45-0000",
+            "078-05-1120",
+            "536-22 1234",
+        ] {
+            assert_eq!(count("us-ssn", bad), 0, "{bad}");
+        }
+    }
+
+    #[test]
+    fn itin_and_ein() {
+        assert_eq!(count("us-itin", "912-70-1234"), 1);
+        assert_eq!(count("us-itin", "912-69-1234"), 0);
+        assert_eq!(count("us-ssn", "912-70-1234"), 0);
+        assert_eq!(count("us-ein", "EIN: 12-3456789"), 1);
+        assert_eq!(count("us-ein", "part 12-3456789"), 0);
+        assert_eq!(count("us-ein", "EIN 07-3456789"), 0);
+    }
+
+    #[test]
+    fn routing_needs_a_word() {
+        assert_eq!(count("us-aba-routing", "Routing number 011000015"), 1);
+        assert_eq!(count("us-aba-routing", "ABA 021000021"), 1);
+        assert_eq!(count("us-aba-routing", "invoice 011000015"), 0);
+        assert_eq!(count("us-aba-routing", "routing 011000016"), 0);
+    }
+
+    #[test]
+    fn licenses() {
+        assert_eq!(count("us-drivers-license", "Driver's license: D1234567"), 1);
+        assert_eq!(count("us-drivers-license", "DL# S123-456-78-901-0"), 1);
+        assert_eq!(count("us-drivers-license", "Order D1234567"), 0);
+    }
+
+    #[test]
+    fn health_identifiers() {
+        // CMS's own MBI example
+        assert_eq!(count("us-mbi", "Medicare 1EG4-TE5-MK73"), 1);
+        assert_eq!(count("us-mbi", "1EG4TE5MK73"), 1);
+        assert_eq!(count("us-mbi", "1EG4-TE5-MK7S"), 0);
+        // CMS's NPI example
+        assert_eq!(count("us-npi", "NPI 1234567893"), 1);
+        assert_eq!(count("us-npi", "NPI 1234567894"), 0);
+        assert_eq!(count("us-npi", "call 1234567893"), 0);
+        assert_eq!(count("us-dea", "DEA AB1234563"), 1);
+        assert_eq!(count("us-dea", "AB1234564"), 0);
+    }
+}

crates/features/src/mailflow/extract.rs

@@ -161,12 +161,14 @@ fn is_text(content_type: &str, extension: &str) -> bool {
 fn decode_text(data: &[u8]) -> String {
     let utf16 = |bytes: &[u8], big: bool| {
         let units: Vec<u16> = bytes
-            .chunks_exact(2)
-            .map(|c| {
+            .as_chunks::<2>()
+            .0
+            .iter()
+            .map(|&c| {
                 if big {
-                    u16::from_be_bytes([c[0], c[1]])
+                    u16::from_be_bytes(c)
                 } else {
-                    u16::from_le_bytes([c[0], c[1]])
+                    u16::from_le_bytes(c)
                 }
             })
             .collect();

docs/spec/features/dlp-and-mail-flow-rules.md

@@ -139,6 +139,14 @@ DLP adds **detectors**. Each counts what it finds, and a rule sets a minimum
   either side, in the languages where the identifier is used ("passport",
   "Reisepass", "pasaporte"...).
 
+A check that about one random number in ten passes (Luhn, mod 10, mod 11) is
+too weak for a bare run of digits: invoice and phone numbers would match. So
+a checked identifier that is only digits (SSN, SIN, NHS, TFN, Medicare…)
+counts alone in the written form it's issued in (`536-22-1234`,
+`130 692 544`, `943 476 5919`), and as bare digits only beside a word. ABA
+routing numbers and NPIs are never written with separators, so they always
+need a word. (Refinement made while building phase 2, 2026-09-28.)
+
 The catalog (settled answer 6: the recognized, protected identifiers, not a
 chosen few). Each row is one table entry and one check function in
 `crates/features/src/mailflow/detectors/`:
@@ -157,10 +165,10 @@ chosen few). Each row is one table entry and one check function in
 | US | Social Security number | Checked | `AAA-GG-SSSS`, or nine digits with a word; never area 000, 666 or 9xx, group 00, serial 0000 |
 | US | ITIN | Checked | 9XX-GG-SSSS with the IRS's group ranges |
 | US | EIN | Needs a word | a valid IRS prefix and seven digits |
-| US | Bank routing number (ABA) | Checked | nine digits, a valid Federal Reserve prefix, the 3-7-1 checksum |
+| US | Bank routing number (ABA) | Needs a word | nine digits, a valid Federal Reserve prefix, the 3-7-1 checksum |
 | US | Driver's license | Needs a word | each state's published format |
 | US | Medicare Beneficiary Identifier | Checked | CMS's 11-character pattern and excluded letters |
-| US | National Provider Identifier | Checked | ten digits, Luhn over the `80840` prefix |
+| US | National Provider Identifier | Needs a word | ten digits, Luhn over the `80840` prefix |
 | US | DEA registration number | Checked | two letters, seven digits, DEA's check digit |
 | UK | National Insurance number | Checked | two letters (HMRC's excluded prefixes), six digits, A–D |
 | UK | NHS number | Checked | ten digits, mod 11 |