Contracts, pods, MATTR and the circuit

pragma circom 2.1.6;

// Proves: the prover knows (income, salt) such that
//   commitment == Poseidon(income, salt)   and   income >= threshold
// without revealing income or salt. Amounts are whole AUD per year, 32-bit.
//
// Public signals (in this order): [threshold, commitment]

include "circomlib/circuits/poseidon.circom";
include "circomlib/circuits/comparators.circom";
include "circomlib/circuits/bitify.circom";

template IncomeGte(n) {
    signal input income;      // private
    signal input salt;        // private
    signal input threshold;   // public
    signal input commitment;  // public

    // Range-check both amounts. GreaterEqThan is only sound for n-bit inputs.
    component incomeBits = Num2Bits(n);
    incomeBits.in <== income;
    component thresholdBits = Num2Bits(n);
    thresholdBits.in <== threshold;

    // Binding: the commitment the pod signed must open to this income.
    component h = Poseidon(2);
    h.inputs[0] <== income;
    h.inputs[1] <== salt;
    commitment === h.out;

    // income >= threshold
    component gte = GreaterEqThan(n);
    gte.in[0] <== income;
    gte.in[1] <== threshold;
    gte.out === 1;
}

component main {public [threshold, commitment]} = IncomeGte(32);

# "CommBank ID – Income Verified": the Commbank ID identity claims (financial-passport) plus the
# CDR-derived income. Issued only through the authorization-code flow, behind the offers gateway.
#   identity  <- cba-issuer claim source (data/customers.json; PF id_token carries only sub)
#   income    <- the same claim source, which merges the pod-runtime income claims (NET income)
branding:
  backgroundColor: '#ffcc00'
  name: CommBank ID – Income Verified
  description: Identity plus income verified from your bank via the Consumer Data Right
claimMappings:
  au.com.cba.commbank_id.1:
    given_name:
      display:
      - locale: en-AU
        name: Given name
      mapFrom: claims.given_name
      required: true
      type: string
    family_name:
      display:
      - locale: en-AU
        name: Family name
      mapFrom: claims.family_name
      required: true
      type: string
    birth_date:
      display:
      - locale: en-AU
        name: Date of birth
      mapFrom: claims.birth_date
      required: false
      type: dateTime
    email:
      display:
      - locale: en-AU
        name: Email
      mapFrom: claims.email
      required: false
      type: string
    resident_country:
      display:
      - locale: en-AU
        name: Country of residence
      mapFrom: claims.resident_country
      defaultValue: AU
      required: false
      type: string
    kyc_level:
      display:
      - locale: en-AU
        name: Identity assurance level
      mapFrom: claims.kyc_level
      required: false
      type: string
    customer_since:
      display:
      - locale: en-AU
        name: Customer since
      mapFrom: claims.customer_since
      required: false
      type: dateTime
    verified_at:
      display:
      - locale: en-AU
        name: Identity verified at
      mapFrom: claims.verified_at
      required: false
      type: dateTime
    age_over_18:
      display:
      - locale: en-AU
        name: Over 18
      mapFrom: claims.age_over_18
      required: false
      type: boolean
  au.com.cba.income.1:
    income_annualised:
      display:
      - locale: en-AU
        name: Annual income (AUD)
      mapFrom: claims.income_annualised
      required: true
      type: number
    income_frequency:
      display:
      - locale: en-AU
        name: Pay frequency
      mapFrom: claims.income_frequency
      required: true
      type: string
    income_employer:
      display:
      - locale: en-AU
        name: Employer
      mapFrom: claims.income_employer
      required: false
      type: string
    income_verified_at:
      display:
      - locale: en-AU
        name: Income verified at
      mapFrom: claims.income_verified_at
      required: true
      type: dateTime
    income_source:
      display:
      - locale: en-AU
        name: Income source
      mapFrom: claims.income_source
      defaultValue: CDR
      required: true
      type: string
    income_commitment:
      display:
      - locale: en-AU
        name: Income commitment
      mapFrom: claims.income_commitment
      required: true
      type: string
claimSourceId: ${CLAIM_SOURCE_ID_CBA_ISSUER}
expiresIn:
  months: 3
includeStatus: true
type: au.com.cba.commbank-id-income

# Claim source for "CommBank ID – Income Verified". MATTR calls it at credential issuance (when
# the wallet retrieves the credential, not at offer time):
#   GET ${OFFERS_API_URL}/claims/mattr?sub=<CBA sub>&purpose=credential-issuance
#   x-api-key: <INTERNAL_API_KEY>   (MATTR sends api-key auth as x-api-key; CONTRACTS v1.1 #6)
# The offers API answers with the customer's identity (data/customers.json - CBA PF's id_token
# carries only sub) merged with the pod's flattened income claims (pod-runtime /claims/mattr,
# purpose credential-issuance). Fields land at claims.*: given_name, family_name, birth_date,
# email, resident_country, kyc_level, verified_at, age_over_18, income_annualised (NET),
# income_frequency, income_employer, income_verified_at, income_source, income_commitment.
# No defaultValue on sub: a missing sub must fail issuance, never fetch someone else's data.
# OFFERS_API_URL must be reachable from MATTR (public HTTPS).
name: cba-issuer-claims
url: ${OFFERS_API_URL}/claims/mattr
requestMethod: GET
requestParameters:
  sub:
    mapFrom: claims.sub
  purpose:
    defaultValue: credential-issuance
authorization:
  type: api-key
  value: '${INTERNAL_API_KEY}'