did-jwt/lib.commonjs/encryption/X25519-ECDH-1PU.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.computeX25519Ecdh1PUv3Kek = computeX25519Ecdh1PUv3Kek;
exports.createX25519Ecdh1PUv3Kek = createX25519Ecdh1PUv3Kek;
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 computeX25519Ecdh1PUv3Kek(recipient, recipientSecret, senderPublicKey, alg) {
    const crv = 'X25519';
    const keyLen = 256;
    const header = recipient.header;
    if (header.epk?.crv !== crv || typeof header.epk.x == 'undefined')
        return null;
    // ECDH-1PU requires additional shared secret between
    // static key of sender and static key of recipient
    const publicKey = (0, util_js_1.base64ToBytes)(header.epk.x);
    let zE;
    let zS;
    if (recipientSecret instanceof Uint8Array) {
        zE = ed25519_js_1.x25519.getSharedSecret(recipientSecret, publicKey);
        zS = ed25519_js_1.x25519.getSharedSecret(recipientSecret, senderPublicKey);
    }
    else {
        zE = await recipientSecret(publicKey);
        zS = await recipientSecret(senderPublicKey);
    }
    const sharedSecret = new Uint8Array(zE.length + zS.length);
    sharedSecret.set(zE);
    sharedSecret.set(zS, zE.length);
    // Key Encryption Key
    let producerInfo;
    let consumerInfo;
    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 createX25519Ecdh1PUv3Kek(recipientPublicKey, senderSecret, alg, // must be provided as this is the key agreement alg + the key wrapper alg, Example: 'ECDH-ES+A256KW'
apu, 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 zE = ed25519_js_1.x25519.getSharedSecret(ephemeral.secretKey, recipientPublicKey);
    // ECDH-1PU requires additional shared secret between
    // static key of sender and static key of recipient
    let zS;
    if (senderSecret instanceof Uint8Array) {
        zS = ed25519_js_1.x25519.getSharedSecret(senderSecret, recipientPublicKey);
    }
    else {
        zS = await senderSecret(recipientPublicKey);
    }
    const sharedSecret = new Uint8Array(zE.length + zS.length);
    sharedSecret.set(zE);
    sharedSecret.set(zS, zE.length);
    let partyUInfo = new Uint8Array(0);
    let partyVInfo = new Uint8Array(0);
    if (apu)
        partyUInfo = (0, util_js_1.base64ToBytes)(apu);
    if (apv)
        partyVInfo = (0, util_js_1.base64ToBytes)(apv);
    // Key Encryption Key
    const kek = (0, Digest_js_1.concatKDF)(sharedSecret, keyLen, alg, partyUInfo, partyVInfo);
    return { epk, kek };
}
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