public void Rfc5869ExtractNullIkm()
{
byte[] salt = new byte[20];
AssertExtensions.Throws <ArgumentNullException>(
"ikm",
() => HKDF.Extract(HashAlgorithmName.SHA1, null, salt));
}
private (byte[], byte[]) DeriveKeyAndNonce(byte[] salt, byte[] authSecret, ECPublicKeyParameters senderPublicKey, ECPublicKeyParameters receiverPublicKey, ECPrivateKeyParameters receiverPrivateKey)
{
var(secret, context) = ExtractSecretAndContext(senderPublicKey, receiverPublicKey, receiverPrivateKey);
secret = HKDF.GetBytes(authSecret, secret, authInfoParameter, SHA_256_LENGTH);
byte[] keyInfo = ByteArray.Concat(keyInfoParameter, context);
byte[] nonceInfo = ByteArray.Concat(nonceInfoParameter, context);
byte[] prk = HKDF.Extract(salt, secret);
return(HKDF.Expand(prk, keyInfo, KEY_LENGTH), HKDF.Expand(prk, nonceInfo, NONCE_LENGTH));
}
[InlineData(10, 20)] // Both offset, output +10 over salt
public void Rfc5869ExtractOverlapsPrkOverSalt(int saltOffset, int outputOffset)
{
ReadOnlySpan <byte> ikm = "0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b".HexToByteArray();
ReadOnlySpan <byte> salt = "000102030405060708090a0b0c".HexToByteArray();
byte[] expectedPrk = "077709362c2e32df0ddc3f0dc47bba6390b6c73bb50f9c3122ec844ad7c2b3e5".HexToByteArray();
int length = Math.Max(ikm.Length, expectedPrk.Length) + Math.Max(saltOffset, outputOffset);
Span <byte> buffer = new byte[length];
Span <byte> saltBuffer = buffer.Slice(saltOffset, salt.Length);
Span <byte> outputBuffer = buffer.Slice(outputOffset, expectedPrk.Length);
salt.CopyTo(saltBuffer);
HKDF.Extract(HashAlgorithmName.SHA256, ikm, saltBuffer, outputBuffer);
Assert.Equal(expectedPrk, outputBuffer.ToArray());
}
public void Rfc5869ExtractPrkTooLong()
{
byte[] prk = new byte[24];
for (int i = 0; i < 4; i++)
{
prk[20 + i] = (byte)(i + 5);
}
byte[] ikm = new byte[20];
byte[] salt = new byte[20];
Assert.Equal(20, HKDF.Extract(HashAlgorithmName.SHA1, ikm, salt, prk));
Assert.Equal("A3CBF4A40F51A53E046F07397E52DF9286AE93A2", prk.AsSpan(0, 20).ByteArrayToHex());
for (int i = 0; i < 4; i++)
{
// ensure we didn't modify anything further
Assert.Equal((byte)(i + 5), prk[20 + i]);
}
}
protected override byte[] Extract(HashAlgorithmName hash, int prkLength, byte[] ikm, byte[] salt)
{
byte[] prk = new byte[prkLength];
Assert.Equal(prkLength, HKDF.Extract(hash, ikm, salt, prk));
return(prk);
}
protected override byte[] Extract(HashAlgorithmName hash, int prkLength, byte[] ikm, byte[] salt)
{
return(HKDF.Extract(hash, ikm, salt));
}