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Update SWIFT PII detection #37

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Merged
merged 2 commits into from
Nov 12, 2025
Merged

Update SWIFT PII detection #37

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3645a84
Update SWIFT PII detection
steven10a Nov 10, 2025
7d2b604
Fix bank codes
steven10a Nov 10, 2025
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41 changes: 38 additions & 3 deletions src/__tests__/unit/checks/pii.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -224,19 +224,54 @@ describe('pii guardrail', () => {
expect(result.info?.checked_text).toBe('cvv=<CVV>');
});

it('detects BIC/SWIFT codes', async () => {
it('detects BIC/SWIFT codes with explicit prefixes', async () => {
const config = PIIConfig.parse({
entities: [PIIEntity.BIC_SWIFT],
block: false,
});
const text = 'Transfer to BIC DEXXDEXX tomorrow.';
const text = 'Transfer to BIC DEUTDEFF500 tomorrow.';

const result = await pii({}, text, config);

expect((result.info?.detected_entities as Record<string, string[]>)?.BIC_SWIFT).toEqual(['DEXXDEXX']);
expect((result.info?.detected_entities as Record<string, string[]>)?.BIC_SWIFT).toEqual([
'DEUTDEFF500',
]);
expect(result.info?.checked_text).toBe('Transfer to BIC <BIC_SWIFT> tomorrow.');
});

it('detects BIC/SWIFT codes from known bank prefixes', async () => {
const config = PIIConfig.parse({
entities: [PIIEntity.BIC_SWIFT],
block: false,
});
const text = 'Send funds to CHASUS33 by Friday.';

const result = await pii({}, text, config);

expect((result.info?.detected_entities as Record<string, string[]>)?.BIC_SWIFT).toEqual(['CHASUS33']);
expect(result.info?.checked_text).toBe('Send funds to <BIC_SWIFT> by Friday.');
});

it('does not flag common words as BIC/SWIFT codes', async () => {
const config = PIIConfig.parse({
entities: [PIIEntity.BIC_SWIFT],
block: false,
});
const texts = [
'The CUSTOMER ordered a product.',
'We will REGISTER your account.',
'Please CONSIDER this option.',
'The DOCUMENT is ready.',
'This is ABSTRACT art.',
];

for (const text of texts) {
const result = await pii({}, text, config);
expect((result.info?.detected_entities as Record<string, string[]>)?.BIC_SWIFT).toBeUndefined();
expect(result.info?.pii_detected).toBe(false);
}
});

it('detects precise street addresses as location', async () => {
const config = PIIConfig.parse({
entities: [PIIEntity.LOCATION],
Expand Down
87 changes: 86 additions & 1 deletion src/checks/pii.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -205,6 +205,88 @@ interface PiiDetectionResult {
spans: ReplacementSpan[];
}

const BIC_CONTEXT_PREFIX_PATTERN = [
'(?:[sS][wW][iI][fF][tT])',
'(?:[bB][iI][cC])',
'(?:[bB][aA][nN][kK][\\s-]?[cC][oO][dD][eE])',
'(?:[sS][wW][iI][fF][tT][\\s-]?[cC][oO][dD][eE])',
'(?:[bB][iI][cC][\\s-]?[cC][oO][dD][eE])',
].join('|');

const BIC_WITH_CONTEXT_REGEX = new RegExp(
`(?:${BIC_CONTEXT_PREFIX_PATTERN})[:\\s=]+([A-Z]{4}[A-Z]{2}[A-Z0-9]{2}(?:[A-Z0-9]{3})?)\\b`,
'g'
);

const KNOWN_BIC_PREFIXES = [
'DEUT',
'CHAS',
'BARC',
'HSBC',
'BNPA',
'CITI',
'WELL',
'BOFA',
'JPMC',
'GSCC',
'MSNY',
'COBA',
'DRSD',
'BYLA',
'MALA',
'HYVE',
'WFBI',
'USBC',
'LOYD',
'MIDL',
'NWBK',
'RBOS',
'CRLY',
'SOGE',
'AGRI',
'UBSW',
'CRES',
'SANB',
'BBVA',
'UNCR',
'BCIT',
'INGB',
'ABNA',
'RABO',
'ROYA',
'TDOM',
'BNSC',
'ANZB',
'NATA',
'WPAC',
'CTBA',
'BKCH',
'MHCB',
'BOTK',
'ICBK',
'ABOC',
'PCBC',
'HSBC',
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Copilot AI Nov 10, 2025

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The prefix 'HSBC' appears twice in the KNOWN_BIC_PREFIXES array (lines 225 and 269). Remove the duplicate entry to avoid redundancy.

Suggested change
'HSBC',

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@steven10a steven10a Nov 10, 2025

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[nit]

'SCBL',
'DBSS',
'OCBC',
'UOVB',
'CZNB',
'SHBK',
'KOEX',
'HVBK',
'NACF',
'IBKO',
'KODB',
'HNBN',
'CITI',
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Copilot AI Nov 10, 2025

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The prefix 'CITI' appears twice in the KNOWN_BIC_PREFIXES array (lines 227 and 282). Remove the duplicate entry to avoid redundancy.

Suggested change
'CITI',

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@steven10a steven10a Nov 10, 2025

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[nit]

];

const KNOWN_BIC_REGEX = new RegExp(
`\\b(?:${KNOWN_BIC_PREFIXES.join('|')})[A-Z]{2}[A-Z0-9]{2}(?:[A-Z0-9]{3})?\\b`,
'g'
);

/**
* Default regex patterns for PII entity types.
*/
Expand Down Expand Up @@ -245,7 +327,10 @@ const DEFAULT_PII_PATTERNS: Record<PIIEntity, PatternDefinition[]> = {
group: 1,
},
],
[PIIEntity.BIC_SWIFT]: [{ regex: /\b[A-Z]{4}[A-Z]{2}[A-Z0-9]{2}(?:[A-Z0-9]{3})?\b/g }],
[PIIEntity.BIC_SWIFT]: [
{ regex: BIC_WITH_CONTEXT_REGEX, group: 1 },
{ regex: KNOWN_BIC_REGEX },
],

// USA
[PIIEntity.US_BANK_NUMBER]: [{ regex: /\b\d{8,17}\b/g }],
Expand Down
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