Sanctions Screening

OFAC SDN, EU, UK HMT sanctions lists, PEP detection, and adverse media screening

The AML screening service (pkg/aml.ScreeningService) checks individuals and entities against global sanctions lists and politically exposed persons databases.

Sanctions Lists

List	Constant	Source	Coverage
OFAC SDN	`ofac_sdn`	US Treasury	Specially Designated Nationals and Blocked Persons
EU Consolidated	`eu_sanctions`	European Union	EU sanctions targets
UK HMT	`uk_hmt`	HM Treasury	UK financial sanctions targets
PEP	`pep`	Multi-source	Politically exposed persons, family, and associates
Adverse Media	`adverse_media`	Multi-source	Negative news screening

All five lists are checked on every screening request. Results include which lists produced matches.

Match Types

The screening service uses three matching strategies:

Match Type	Constant	Method
Exact	`exact`	Case-insensitive string equality after normalization
Fuzzy	`fuzzy`	Levenshtein distance with configurable similarity threshold
Partial	`partial`	Substring and token-level matching on name components

Fuzzy matching uses Levenshtein edit distance to find near-matches. The Levenshtein distance counts the minimum number of single-character insertions, deletions, or substitutions needed to transform one string into another. A similarity score is calculated as:

similarity = 1 - (distance / max(len(a), len(b)))

Names with similarity above the configured threshold (typically 0.85) are flagged as fuzzy matches. This catches common variations: transliteration differences, typos, and alternate spellings.

Risk Scoring

Each screening result receives a risk level that determines the required action:

Risk Level	Constant	Action Required
Low	`low`	Auto-approve, periodic rescreening
Medium	`medium`	Manual review within 24 hours
High	`high`	Escalate to compliance officer
Critical	`critical`	Block immediately, file SAR

Risk is determined by match quality, list source, and number of matches. An exact match on the OFAC SDN list produces critical. A fuzzy match on adverse media produces medium.

PEP Detection

Politically exposed persons (current and former government officials, their family members, and close associates) trigger enhanced due diligence:

Source of wealth verification
Source of funds documentation
Senior management approval for onboarding
Enhanced ongoing monitoring (quarterly review)

Enhanced Due Diligence

EDD is required for:

PEP matches (any match type)
High-risk jurisdictions
Complex ownership structures
Unusual transaction patterns

Screening Hit --> Risk Assessment --> EDD Required?
                                         |
                      +------------------+
                      v                  v
                  Standard CDD       Enhanced CDD
                  (periodic)         (source of funds,
                                      senior approval)

List Management

Sanctions lists are loaded at startup and can be refreshed without restart. The screening service uses sync.RWMutex for thread-safe concurrent access during list updates and screening operations.

API

Screen an individual:

curl -X POST http://localhost:8091/v1/aml/screen \
  -H "X-Api-Key: $API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"name":"John Doe","country":"US","date_of_birth":"1980-01-15"}'

See the API Reference for full request/response details.