did-jwt/lib.commonjs/encryption/X25519-ECDH-ES.js

Library for Signing and Verifying JWTs that use DIDs as issuers and JWEs that use DIDs as recipients

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.computeX25519EcdhEsKek = computeX25519EcdhEsKek;
exports.createX25519EcdhEsKek = createX25519EcdhEsKek;
const util_js_1 = require("../util.js");
const Digest_js_1 = require("../Digest.js");
const ed25519_js_1 = require("@noble/curves/ed25519.js");
async function computeX25519EcdhEsKek(recipient, receiverSecret, alg) {
    const crv = 'X25519';
    const keyLen = 256;
    const header = recipient.header;
    if (header.epk?.crv !== crv || typeof header.epk.x == 'undefined')
        return null;
    const publicKey = (0, util_js_1.base64ToBytes)(header.epk.x);
    let sharedSecret;
    if (receiverSecret instanceof Uint8Array) {
        sharedSecret = ed25519_js_1.x25519.getSharedSecret(receiverSecret, publicKey);
    }
    else {
        sharedSecret = await receiverSecret(publicKey);
    }
    // Key Encryption Key
    let producerInfo = undefined;
    let consumerInfo = undefined;
    if (recipient.header.apu)
        producerInfo = (0, util_js_1.base64ToBytes)(recipient.header.apu);
    if (recipient.header.apv)
        consumerInfo = (0, util_js_1.base64ToBytes)(recipient.header.apv);
    return (0, Digest_js_1.concatKDF)(sharedSecret, keyLen, alg, producerInfo, consumerInfo);
}
async function createX25519EcdhEsKek(recipientPublicKey, senderSecret, // unused
alg, apu, // unused
apv, ephemeralKeyPair) {
    const crv = 'X25519';
    const keyLen = 256;
    const ephemeral = ephemeralKeyPair ? (0, util_js_1.generateKeyPairFromSeed)(ephemeralKeyPair.secretKey) : (0, util_js_1.generateKeyPair)();
    const epk = { kty: 'OKP', crv, x: (0, util_js_1.bytesToBase64url)(ephemeral.publicKey) };
    const sharedSecret = ed25519_js_1.x25519.getSharedSecret(ephemeral.secretKey, recipientPublicKey);
    // Key Encryption Key
    const consumerInfo = (0, util_js_1.base64ToBytes)(apv ?? '');
    const kek = (0, Digest_js_1.concatKDF)(sharedSecret, keyLen, alg, undefined, consumerInfo);
    return { epk, kek };
}
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