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* Removed SHA1 implementation from ECDH
This commit is contained in:
Gabriel Tofvesson 2018-04-09 10:08:06 +02:00
parent 41e8d969ed
commit de2a53c1cf
1 changed files with 1 additions and 93 deletions
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Common/Cryptography/KeyExchange/EllipticDiffieHellman.cs
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@ -76,99 +76,7 @@ namespace Common.Cryptography.KeyExchange
Point remotePublic = new Point(new BigInteger(p1), new BigInteger(p2));
byte[] secret = curve.Multiply(remotePublic, priv).X.ToByteArray(); // Use the x-coordinate as the shared secret
// SHA-1 (Common shared secret generation method)
// Initialize buffers
uint h0 = 0x67452301;
uint h1 = 0xEFCDAB89;
uint h2 = 0x98BADCFE;
uint h3 = 0x10325476;
uint h4 = 0xC3D2E1F0;
// Pad message
int ml = secret.Length + 1;
byte[] msg = new byte[ml + ((960 - (ml * 8 % 512)) % 512) / 8 + 8];
Array.Copy(secret, msg, secret.Length);
msg[secret.Length] = 0x80;
long len = secret.Length * 8;
for (int i = 0; i < 8; ++i) msg[msg.Length - 1 - i] = (byte)((len >> (i * 8)) & 255);
//Support.WriteToArray(msg, message.Length * 8, msg.Length - 8);
//for (int i = 0; i <4; ++i) msg[msg.Length - 5 - i] = (byte)(((message.Length*8) >> (i * 8)) & 255);
int chunks = msg.Length / 64;
// Perform hashing for each 512-bit block
for (int i = 0; i < chunks; ++i)
{
// Split block into words
uint[] w = new uint[80];
for (int j = 0; j < 16; ++j)
w[j] |= (uint)((msg[i * 64 + j * 4] << 24) | (msg[i * 64 + j * 4 + 1] << 16) | (msg[i * 64 + j * 4 + 2] << 8) | (msg[i * 64 + j * 4 + 3] << 0));
// Expand words
for (int j = 16; j < 80; ++j)
w[j] = Rot(w[j - 3] ^ w[j - 8] ^ w[j - 14] ^ w[j - 16], 1);
// Initialize chunk-hash
uint
a = h0,
b = h1,
c = h2,
d = h3,
e = h4;
// Do hash rounds
for (int t = 0; t < 80; ++t)
{
uint tmp = ((a << 5) | (a >> (27))) +
( // Round-function
t < 20 ? (b & c) | ((~b) & d) :
t < 40 ? b ^ c ^ d :
t < 60 ? (b & c) | (b & d) | (c & d) :
/*t<80*/ b ^ c ^ d
) +
e +
( // K-function
t < 20 ? 0x5A827999 :
t < 40 ? 0x6ED9EBA1 :
t < 60 ? 0x8F1BBCDC :
/*t<80*/ 0xCA62C1D6
) +
w[t];
e = d;
d = c;
c = Rot(b, 30);
b = a;
a = tmp;
}
h0 += a;
h1 += b;
h2 += c;
h3 += d;
h4 += e;
}
return WriteContiguous(new byte[20], 0, SwapEndian(h0), SwapEndian(h1), SwapEndian(h2), SwapEndian(h3), SwapEndian(h4));
}
private static uint Rot(uint val, int by) => (val << by) | (val >> (32 - by));
// Swap endianness of a given integer
private static uint SwapEndian(uint value) => (uint)(((value >> 24) & (255 << 0)) | ((value >> 8) & (255 << 8)) | ((value << 8) & (255 << 16)) | ((value << 24) & (255 << 24)));
private static byte[] WriteToArray(byte[] target, uint data, int offset)
{
for (int i = 0; i < 4; ++i)
target[i + offset] = (byte)((data >> (i * 8)) & 255);
return target;
}
private static byte[] WriteContiguous(byte[] target, int offset, params uint[] data)
{
for (int i = 0; i < data.Length; ++i) WriteToArray(target, data[i], offset + i * 4);
return target;
return curve.Multiply(remotePublic, priv).X.ToByteArray(); // Use the x-coordinate as the shared secret
}
public static EllipticDiffieHellman Curve25519(BigInteger priv) => new EllipticDiffieHellman(c_25519, c_25519_gen, c_25519_order, priv.ToByteArray());