8 changed files with 496 additions and 12 deletions
@ -0,0 +1,8 @@ |
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import {DIDResolutionResult} from "did-resolver"; |
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|
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declare module './did-eth-local-resolver.js' { |
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const value: { |
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didEthLocalResolver: (jwt: string) => Promise<DIDResolutionResult>; |
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}; |
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export default value; |
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} |
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@ -0,0 +1,139 @@ |
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import { AsnParser } from "@peculiar/asn1-schema"; |
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import { ECDSASigValue } from "@peculiar/asn1-ecc"; |
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import crypto from "crypto"; |
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import { decode as cborDecode } from "cbor-x"; |
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|
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/** |
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* |
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* |
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* similar code is in crowd-funder-for-time-pwa libs/crypto/vc/passkeyDidPeer.ts verifyJwtWebCrypto |
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* |
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* @returns {Promise<boolean>} |
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*/ |
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export async function verifyPeerSignature( |
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payloadBytes: Uint8Array, |
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publicKeyBytes: Uint8Array, |
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signatureBytes: Uint8Array |
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) { |
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// this simple approach doesn't work
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//const verify = crypto.createVerify('sha256')
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//verify.update(preimage)
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//const result = verify.verify(publicKey, signature)
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const finalSignatureBuffer = unwrapEC2Signature(signatureBytes); |
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const verifyAlgorithm = { |
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name: "ECDSA", |
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hash: { name: "SHA-256" }, |
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}; |
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const publicKeyJwk = cborToKeys(publicKeyBytes).publicKeyJwk; |
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const keyAlgorithm = { |
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name: "ECDSA", |
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namedCurve: publicKeyJwk.crv, |
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}; |
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const publicKeyCryptoKey = await crypto.subtle.importKey( |
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"jwk", |
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publicKeyJwk, |
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keyAlgorithm, |
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false, |
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["verify"], |
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); |
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const verified = await crypto.subtle.verify( |
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verifyAlgorithm, |
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publicKeyCryptoKey, |
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finalSignatureBuffer, |
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payloadBytes, |
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); |
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return verified; |
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} |
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|
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function cborToKeys(publicKeyBytes: Uint8Array) { |
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const jwkObj = cborDecode(publicKeyBytes); |
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if ( |
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jwkObj[1] != 2 || // kty "EC"
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jwkObj[3] != -7 || // alg "ES256"
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jwkObj[-1] != 1 || // crv "P-256"
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jwkObj[-2].length != 32 || // x
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jwkObj[-3].length != 32 // y
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) { |
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throw new Error("Unable to extract key."); |
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} |
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const publicKeyJwk = { |
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alg: "ES256", |
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crv: "P-256", |
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kty: "EC", |
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x: arrayToBase64Url(jwkObj[-2]), |
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y: arrayToBase64Url(jwkObj[-3]), |
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}; |
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const publicKeyBuffer = Buffer.concat([ |
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Buffer.from(jwkObj[-2]), |
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Buffer.from(jwkObj[-3]), |
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]); |
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return { publicKeyJwk, publicKeyBuffer }; |
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} |
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function toBase64Url(anythingB64: string) { |
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return anythingB64.replace(/\+/g, "-").replace(/\//g, "_").replace(/=+$/, ""); |
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} |
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function arrayToBase64Url(anything: Uint8Array) { |
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return toBase64Url(Buffer.from(anything).toString("base64")); |
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} |
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/** |
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* In WebAuthn, EC2 signatures are wrapped in ASN.1 structure so we need to peel r and s apart. |
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* |
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* See https://www.w3.org/TR/webauthn-2/#sctn-signature-attestation-types
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* |
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* @return Uint8Array of the signature inside |
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*/ |
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function unwrapEC2Signature(signature: Uint8Array) { |
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const parsedSignature = AsnParser.parse(signature, ECDSASigValue); |
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let rBytes = new Uint8Array(parsedSignature.r); |
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let sBytes = new Uint8Array(parsedSignature.s); |
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if (shouldRemoveLeadingZero(rBytes)) { |
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rBytes = rBytes.slice(1); |
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} |
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if (shouldRemoveLeadingZero(sBytes)) { |
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sBytes = sBytes.slice(1); |
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} |
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const finalSignature = isoUint8ArrayConcat([rBytes, sBytes]); |
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return finalSignature; |
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} |
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/** |
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* Determine if the DER-specific `00` byte at the start of an ECDSA signature byte sequence |
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* should be removed based on the following logic: |
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* |
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* "If the leading byte is 0x0, and the high order bit on the second byte is not set to 0, |
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* then remove the leading 0x0 byte" |
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* |
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* @return true if leading zero should be removed |
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*/ |
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function shouldRemoveLeadingZero(bytes: Uint8Array) { |
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return bytes[0] === 0x0 && (bytes[1] & (1 << 7)) !== 0; |
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} |
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// from https://github.com/MasterKale/SimpleWebAuthn/blob/master/packages/server/src/helpers/iso/isoUint8Array.ts#L49
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/** |
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* Combine multiple Uint8Arrays into a single Uint8Array |
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* |
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* @param arrays - Uint8Array[] |
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* @return Uint8Array |
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*/ |
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function isoUint8ArrayConcat(arrays: Uint8Array[]) { |
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let pointer = 0; |
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const totalLength = arrays.reduce((prev, curr) => prev + curr.length, 0); |
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const toReturn = new Uint8Array(totalLength); |
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arrays.forEach((arr) => { |
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toReturn.set(arr, pointer); |
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pointer += arr.length; |
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}); |
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return toReturn; |
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} |
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@ -0,0 +1,104 @@ |
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import crypto from "crypto"; |
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import didJwt from "did-jwt"; |
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import {PEER_DID_PREFIX, TEST_BYPASS_ENV_VALUE} from "./index"; |
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import {verifyPeerSignature} from "./didPeer"; |
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/** |
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* |
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* @param payload |
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* @param issuerDid |
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* @param signatureString |
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* @returns {Promise<{claimPayload: string, verified: boolean}>} |
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*/ |
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export async function verifyJwt(payload: any, issuerDid: any, signatureString: any) { |
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if (!payload.iss) { |
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return Promise.reject({ |
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clientError: { |
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message: `JWT is missing an "iss" field.`, |
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} |
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}) |
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} |
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let nowEpoch = Math.floor(new Date().getTime() / 1000) |
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if (!payload.exp) { |
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return Promise.reject({ |
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clientError: { |
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message: `JWT with is missing an "exp" field.`, |
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} |
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}) |
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} |
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if (payload.exp < nowEpoch && process.env.NODE_ENV !== TEST_BYPASS_ENV_VALUE) { |
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return Promise.reject({ |
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clientError: { |
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message: `JWT with exp ${payload.exp} has expired.`, |
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} |
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}); |
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} |
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const authData: string = payload.AuthenticationDataB64URL |
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const clientData: string = payload.ClientDataJSONB64URL |
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if (!authData || !clientData) { |
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return Promise.reject({ |
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clientError: { |
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message: `JWT with typ == JWANT requires AuthenticationData and ClientDataJSON.` |
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} |
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}) |
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} |
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const decodedAuthDataBuff = Buffer.from(authData, 'base64url') |
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const decodedClientData = Buffer.from(clientData, 'base64url') |
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let claimPayload = JSON.parse(decodedClientData.toString()) |
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if (claimPayload.challenge) { |
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claimPayload = JSON.parse(Buffer.from(claimPayload.challenge, "base64url").toString()) |
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if (!claimPayload.exp) { |
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claimPayload.exp = payload.exp |
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} |
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if (!claimPayload.iat) { |
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claimPayload.iat = payload.iat |
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} |
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if (!claimPayload.iss) { |
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claimPayload.iss = payload.iss |
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} |
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} |
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if (!claimPayload.exp) { |
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return Promise.reject({ |
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clientError: { |
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message: `JWT client data challenge is missing an "exp" field.`, |
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} |
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}) |
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} |
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if (claimPayload.exp < nowEpoch && process.env.NODE_ENV !== TEST_BYPASS_ENV_VALUE) { |
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return Promise.reject({ |
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clientError: { |
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message: `JWT client data challenge exp time is past.`, |
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} |
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}) |
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} |
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if (claimPayload.exp !== payload.exp) { |
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return Promise.reject({ |
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clientError: { |
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message: `JWT client data challenge "exp" field doesn't match the outside payload "exp".`, |
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} |
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}) |
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} |
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if (claimPayload.iss !== payload.iss) { |
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return Promise.reject({ |
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clientError: { |
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message: `JWT client data challenge "iss" field doesn't match the outside payload "iss".`, |
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} |
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}) |
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} |
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const hashedClientDataBuff = crypto.createHash("sha256") |
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.update(decodedClientData) |
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.digest() |
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const preimage = new Uint8Array(Buffer.concat([decodedAuthDataBuff, hashedClientDataBuff])) |
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const PEER_DID_MULTIBASE_PREFIX = PEER_DID_PREFIX + "0" |
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// Uint8Array
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const publicKey = didJwt.multibaseToBytes(issuerDid.substring(PEER_DID_MULTIBASE_PREFIX.length)); |
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const signature = new Uint8Array(Buffer.from(signatureString, 'base64url')) |
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const verified = await verifyPeerSignature(preimage, publicKey, signature) |
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return { claimPayload, verified } |
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|
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} |
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