private static byte[] F(byte[] salt, int iterationCount, int blockIndex, HMAC prf)
{
byte[] numArray = prf.ComputeHash(Arrays.Concat(new byte[][] { salt, Arrays.IntToBytes(blockIndex) }));
byte[] numArray1 = numArray;
for (int i = 2; i <= iterationCount; i++)
{
numArray = prf.ComputeHash(numArray);
numArray1 = Arrays.Xor(numArray1, numArray);
}
return(numArray1);
}
private byte[] DeriveKey(IDictionary <string, object> header, int cekSizeBits, CngKey externalPublicKey, CngKey privateKey)
{
byte[] bytes = Encoding.UTF8.GetBytes((string)header[this.algIdHeader]);
byte[] numArray = (header.ContainsKey("apv") ? Base64Url.Decode((string)header["apv"]) : Arrays.Empty);
byte[] numArray1 = (header.ContainsKey("apu") ? Base64Url.Decode((string)header["apu"]) : Arrays.Empty);
byte[] numArray2 = Arrays.Concat(new byte[][] { Arrays.IntToBytes((int)bytes.Length), bytes });
byte[] numArray3 = Arrays.Concat(new byte[][] { Arrays.IntToBytes((int)numArray1.Length), numArray1 });
byte[] numArray4 = Arrays.Concat(new byte[][] { Arrays.IntToBytes((int)numArray.Length), numArray });
byte[] bytes1 = Arrays.IntToBytes(cekSizeBits);
return(ConcatKDF.DeriveKey(externalPublicKey, privateKey, cekSizeBits, numArray2, numArray4, numArray3, bytes1));
}
private byte[] DeriveKey(IDictionary <string, object> header, int cekSizeBits, CngKey externalPublicKey, CngKey privateKey)
{
byte[] enc = Encoding.UTF8.GetBytes((string)header[algIdHeader]);
byte[] apv = header.ContainsKey("apv") ? Base64Url.Decode((string)header["apv"]) : Arrays.Empty;
byte[] apu = header.ContainsKey("apu") ? Base64Url.Decode((string)header["apu"]) : Arrays.Empty;
byte[] algorithmId = Arrays.Concat(Arrays.IntToBytes(enc.Length), enc);
byte[] partyUInfo = Arrays.Concat(Arrays.IntToBytes(apu.Length), apu);
byte[] partyVInfo = Arrays.Concat(Arrays.IntToBytes(apv.Length), apv);
byte[] suppPubInfo = Arrays.IntToBytes(cekSizeBits);
return(ConcatKDF.DeriveKey(externalPublicKey, privateKey, cekSizeBits, algorithmId, partyVInfo, partyUInfo, suppPubInfo));
}
private static byte[] F(byte[] salt, int iterationCount, int blockIndex, HMAC prf)
{
byte[] U = prf.ComputeHash(Arrays.Concat(salt, Arrays.IntToBytes(blockIndex))); // U_1 = PRF (P, S || INT (i))
byte[] result = U;
for (int i = 2; i <= iterationCount; i++)
{
U = prf.ComputeHash(U); // U_c = PRF (P, U_{c-1}) .
result = Arrays.Xor(result, U); // U_1 \xor U_2 \xor ... \xor U_c
}
return(result);
}