suzanne.soy/fork-openpgpjs
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Make ephemeral secret available from ECDH module

Browse Source
This commit is contained in:
Aron Wussler 2019-01-18 16:06:57 +01:00
parent 1ec216a6b4
commit 06952b4e30
1 changed files with 52 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

70
src/crypto/public_key/elliptic/ecdh.js
View File

@ -58,6 +58,30 @@ async function kdf(hash_algo, X, length, param) {
return digest.subarray(0, length);
}
/**
* Generate ECDHE ephemeral key and secret from public key
*
* @param {module:type/oid} oid Elliptic curve object identifier
* @param {module:enums.symmetric} cipher_algo Symmetric cipher to use
* @param {module:enums.hash} hash_algo Hash algorithm to use
* @param {Uint8Array} Q Recipient public key
* @param {String} fingerprint Recipient fingerprint
* @returns {Promise<{V: BN, C: Uint8Array}>} Returns public part of ephemeral key and generated ephemeral secret
* @async
*/
async function genPublicEphemeralKey(oid, cipher_algo, hash_algo, Q, fingerprint) {
const curve = new Curve(oid);
const param = buildEcdhParam(enums.publicKey.ecdh, oid, cipher_algo, hash_algo, fingerprint);
cipher_algo = enums.read(enums.symmetric, cipher_algo);
const v = await curve.genKeyPair();
Q = curve.keyFromPublic(Q);
const S = v.derive(Q);
const Z = await kdf(hash_algo, S, cipher[cipher_algo].keySize, param);
return {
V: new BN(v.getPublic()),
Z: Z
};
}
/**
* Encrypt and wrap a session key
@ -68,22 +92,38 @@ async function kdf(hash_algo, X, length, param) {
* @param {module:type/mpi} m Value derived from session key (RFC 6637)
* @param {Uint8Array} Q Recipient public key
* @param {String} fingerprint Recipient fingerprint
* @returns {Promise<{V: BN, C: BN}>} Returns ephemeral key and encoded session key
* @returns {Promise<{V: BN, C: BN}>} Returns public part of ephemeral key and encoded session key
* @async
*/
async function encrypt(oid, cipher_algo, hash_algo, m, Q, fingerprint) {
const key = await genPublicEphemeralKey(oid, cipher_algo, hash_algo, Q, fingerprint);
const C = aes_kw.wrap(key.Z, m.toString());
return {
V: key.V,
C: C
};
}
/**
* Generate ECDHE secret from private key and public part of ephemeral key
*
* @param {module:type/oid} oid Elliptic curve object identifier
* @param {module:enums.symmetric} cipher_algo Symmetric cipher to use
* @param {module:enums.hash} hash_algo Hash algorithm to use
* @param {BN} V Public part of ephemeral key
* @param {Uint8Array} d Recipient private key
* @param {String} fingerprint Recipient fingerprint
* @returns {Promise<Uint8Array>} Generated ephemeral secret
* @async
*/
async function genPrivateEphemeralKey(oid, cipher_algo, hash_algo, V, d, fingerprint) {
const curve = new Curve(oid);
const param = buildEcdhParam(enums.publicKey.ecdh, oid, cipher_algo, hash_algo, fingerprint);
cipher_algo = enums.read(enums.symmetric, cipher_algo);
const v = await curve.genKeyPair();
Q = curve.keyFromPublic(Q);
const S = v.derive(Q);
const Z = await kdf(hash_algo, S, cipher[cipher_algo].keySize, param);
const C = aes_kw.wrap(Z, m.toString());
return {
V: new BN(v.getPublic()),
C: C
};
V = curve.keyFromPublic(V);
d = curve.keyFromPrivate(d);
const S = d.derive(V);
return kdf(hash_algo, S, cipher[cipher_algo].keySize, param);
}
/**
@ -100,14 +140,8 @@ async function encrypt(oid, cipher_algo, hash_algo, m, Q, fingerprint) {
* @async
*/
async function decrypt(oid, cipher_algo, hash_algo, V, C, d, fingerprint) {
const curve = new Curve(oid);
const param = buildEcdhParam(enums.publicKey.ecdh, oid, cipher_algo, hash_algo, fingerprint);
cipher_algo = enums.read(enums.symmetric, cipher_algo);
V = curve.keyFromPublic(V);
d = curve.keyFromPrivate(d);
const S = d.derive(V);
const Z = await kdf(hash_algo, S, cipher[cipher_algo].keySize, param);
const Z = await genPrivateEphemeralKey(oid, cipher_algo, hash_algo, V, d, fingerprint);
return new BN(aes_kw.unwrap(Z, C));
}
export default { encrypt, decrypt };
export default { encrypt, decrypt, genPublicEphemeralKey, genPrivateEphemeralKey };