4 changed files with 266 additions and 2 deletions
@ -0,0 +1,130 @@ |
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import { decode as cborDecode } from "cbor-x"; |
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import { createJWS, JWTPayload } from "did-jwt"; |
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export async function registerCredential() { |
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const publicKeyOptions: PublicKeyCredentialCreationOptions = { |
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challenge: new Uint8Array(32), // Random challenge
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rp: { |
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name: "Time Safari", |
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id: window.location.hostname, |
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}, |
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user: { |
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id: new Uint8Array(16), // User ID
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name: "user@example.com", |
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displayName: "Example User", |
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}, |
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pubKeyCredParams: [ |
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{ |
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type: "public-key", |
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alg: -7, // ES256 algorithm
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}, |
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], |
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authenticatorSelection: { |
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authenticatorAttachment: "platform", |
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userVerification: "preferred", |
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}, |
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timeout: 60000, |
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attestation: "direct", |
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}; |
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const credential = await navigator.credentials.create({ |
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publicKey: publicKeyOptions, |
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}); |
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console.log("credential", credential); |
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const attestationResponse = credential?.response; |
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// Parse the attestation response to get the public key
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const clientDataJSON = attestationResponse.clientDataJSON; |
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console.log("clientDataJSON", clientDataJSON); |
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const attestationObject = cborDecode( |
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new Uint8Array(attestationResponse.attestationObject), |
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); |
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const authData = new Uint8Array(attestationObject.authData); |
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const publicKey = extractPublicKey(authData); |
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return publicKey; |
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} |
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// @ts-expect-error just because it doesn't like the "any"
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function extractPublicKey(authData) { |
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// Extract the public key from authData using appropriate parsing
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// This involves extracting the COSE key format and converting it to JWK
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// For simplicity, we'll assume the public key is at a certain position in authData
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const publicKeyCose = authData.slice(authData.length - 77); // Example position
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const publicKeyJwk = coseToJwk(publicKeyCose); |
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return publicKeyJwk; |
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} |
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// @ts-expect-error just because it doesn't like the "any"
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function coseToJwk(coseKey) { |
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// Convert COSE key format to JWK
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// This is simplified and needs appropriate parsing and conversion logic
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return { |
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kty: "EC", |
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crv: "P-256", |
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x: btoa(coseKey.slice(2, 34)), |
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y: btoa(coseKey.slice(34, 66)), |
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}; |
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} |
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async function generateWebAuthnSignature( |
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dataToSign: string | Uint8Array, |
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credentialID: ArrayBuffer, |
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) { |
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if (!(dataToSign instanceof Uint8Array)) { |
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dataToSign = new TextEncoder().encode(dataToSign as string); |
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} |
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const challenge = dataToSign; |
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const options = { |
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challenge: challenge, |
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allowCredentials: [{ id: credentialID, type: "public-key" }], |
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userVerification: "preferred", |
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}; |
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const assertion = await navigator.credentials.get({ publicKey: options }); |
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const authenticatorAssertionResponse = assertion?.response; |
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return { |
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signature: authenticatorAssertionResponse.signature, |
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clientDataJSON: authenticatorAssertionResponse.clientDataJSON, |
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authenticatorData: authenticatorAssertionResponse.authenticatorData, |
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}; |
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} |
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async function webAuthnES256KSigner(credentialID: ArrayBuffer) { |
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return async (data: string | Uint8Array) => { |
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// also has clientDataJSON
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const { signature, authenticatorData } = await generateWebAuthnSignature( |
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data, |
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credentialID, |
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); |
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// Combine the WebAuthn components into a single signature format as required by did-jwt
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const combinedSignature = Buffer.concat([ |
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Buffer.from(authenticatorData), |
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Buffer.from(signature), |
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]); |
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return combinedSignature.toString("base64"); |
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}; |
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} |
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export async function createJwt( |
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payload: object, |
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issuerDid: string, |
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credentialId: ArrayBuffer, |
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) { |
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const signer = await webAuthnES256KSigner(credentialId); |
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// from createJWT in did-jwt/src/JWT.ts
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const header: JWTPayload = { typ: "JWT", alg: "ES256K" }; |
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const timestamps: Partial<JWTPayload> = { |
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iat: Math.floor(Date.now() / 1000), |
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exp: undefined, |
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}; |
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const fullPayload = { ...timestamps, ...payload, iss: issuerDid }; |
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return createJWS(fullPayload, signer, header); |
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} |
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