private byte[] SetServerHandshakeDigest2(byte[] c1, DigestPosition pos)
{
var hash = ComputeHandshakeDigest2(c1, pos, c1, GenuineFMSKey);
Array.Copy(hash, 0, c1, c1.Length - 32, 32);
return(c1);
}
private byte[] ComputeHandshakeDigest2(byte[] keyvec, DigestPosition keypos, byte[] vec, byte[] key)
{
var doffset = GetDigestOffset(keyvec, keypos);
var hasher1 = new System.Security.Cryptography.HMACSHA256(key);
var key2 = hasher1.ComputeHash(keyvec, doffset, 32);
var hasher2 = new System.Security.Cryptography.HMACSHA256(key2);
return(hasher2.ComputeHash(vec, 0, vec.Length - 32));
}
private byte[] SetServerHandshakeDigest1(byte[] vec, DigestPosition pos)
{
var doffset = GetDigestOffset(vec, pos);
var key = new byte[36];
Array.Copy(GenuineFMSKey, key, 36);
var hash = ComputeHandshakeDigest1(vec, key, doffset);
Array.Copy(hash, 0, vec, doffset, 32);
return(vec);
}
private int GetDigestOffset(byte[] vec, DigestPosition pos)
{
switch (pos)
{
case DigestPosition.First:
return((vec[8] + vec[9] + vec[10] + vec[11]) % 728 + 12);
case DigestPosition.Second:
return((vec[772] + vec[773] + vec[774] + vec[775]) % 728 + 776);
default:
throw new ArgumentException();
}
}
private bool ValidateClientHandshakeDigest2(byte[] vec, byte[] s1, DigestPosition pos)
{
var hash = ComputeHandshakeDigest2(s1, pos, vec, GenuineFPKey);
return(Enumerable.Range(vec.Length - 32, 32).Select(i => vec[i]).SequenceEqual(hash));
}
private bool ValidateClientHandshakeDigest2(byte[] vec, byte[] s1, DigestPosition pos)
{
var hash = ComputeHandshakeDigest2(s1, pos, vec, GenuineFPKey);
return Enumerable.Range(vec.Length-32, 32).Select(i => vec[i]).SequenceEqual(hash);
}
private byte[] SetServerHandshakeDigest2(byte[] c1, DigestPosition pos)
{
var hash = ComputeHandshakeDigest2(c1, pos, c1, GenuineFMSKey);
Array.Copy(hash, 0, c1, c1.Length-32, 32);
return c1;
}
private byte[] SetServerHandshakeDigest1(byte[] vec, DigestPosition pos)
{
var doffset = GetDigestOffset(vec, pos);
var key = new byte[36];
Array.Copy(GenuineFMSKey, key, 36);
var hash = ComputeHandshakeDigest1(vec, key, doffset);
Array.Copy(hash, 0, vec, doffset, 32);
return vec;
}
private byte[] ComputeHandshakeDigest2(byte[] keyvec, DigestPosition keypos, byte[] vec, byte[] key)
{
var doffset = GetDigestOffset(keyvec, keypos);
var hasher1 = new System.Security.Cryptography.HMACSHA256(key);
var key2 = hasher1.ComputeHash(keyvec, doffset, 32);
var hasher2 = new System.Security.Cryptography.HMACSHA256(key2);
return hasher2.ComputeHash(vec, 0, vec.Length-32);
}
private int GetDigestOffset(byte[] vec, DigestPosition pos)
{
switch (pos) {
case DigestPosition.First:
return (vec[8]+vec[9]+vec[10]+vec[11]) % 728 + 12;
case DigestPosition.Second:
return (vec[772]+vec[773]+vec[774]+vec[775]) % 728 + 776;
default:
throw new ArgumentException();
}
}