private static EncryptionKeys GenerateHMAC_SHA1Keys(BigInteger K, string H, string sessionIdentifier)
{
EncryptionKeys keys = new EncryptionKeys();
List <byte> forHash = new List <byte>();
keys.MAClength = 20;
var K_array = K.ToByteArrayUnsigned();
var K_size = K_array.Length;
var K_size_array = BitConverter.GetBytes(K_size);
// reverse zbog toga da ide iz little u big endian - ("normalni")
Array.Reverse(K_size_array);
var H_array = Convert.FromBase64String(H);
var H_size = H_array.Length;
var H_size_array = BitConverter.GetBytes(H_size);
// reverse zbog toga da ide iz little u big endian - ("normalni")
Array.Reverse(H_size_array);
var sessionIdent_array = Convert.FromBase64String(sessionIdentifier);
var sessionIdent_size = sessionIdent_array.Length;
var sessionIdent_size_array = BitConverter.GetBytes(sessionIdent_size);
// reverse zbog toga da ide iz little u big endian - ("normalni")
Array.Reverse(sessionIdent_size_array);
var A = Convert.ToByte('A');
var B = Convert.ToByte('B');
var C = Convert.ToByte('C');
var D = Convert.ToByte('D');
var E = Convert.ToByte('E');
var F = Convert.ToByte('F');
var KH_array = new List <byte>();
KH_array.AddRange(K_size_array);
KH_array.AddRange(K_array);
KH_array.AddRange(H_size_array);
KH_array.AddRange(H_array);
// MAC ključ k -> s
forHash.Clear();
forHash.AddRange(KH_array);
forHash.Add(E);
forHash.AddRange(sessionIdent_array);
using (SHA1Managed sha1 = new SHA1Managed())
{
keys.MACKeyCS = sha1.ComputeHash(forHash.ToArray());
}
// MAC ključ s -> k
forHash.Clear();
forHash.AddRange(KH_array);
forHash.Add(F);
forHash.AddRange(sessionIdent_array);
using (SHA1Managed sha1 = new SHA1Managed())
{
keys.MACKeySC = sha1.ComputeHash(forHash.ToArray());
}
return(keys);
}
private static EncryptionKeys Generate3DESKeys(BigInteger K, string H, string sessionIdentifier)
{
EncryptionKeys keys = new EncryptionKeys();
List <byte> forHash = new List <byte>();
var K_array = K.ToByteArrayUnsigned();
var K_size = K_array.Length;
var K_size_array = BitConverter.GetBytes(K_size);
// reverse zbog toga da ide iz little u big endian - ("normalni")
Array.Reverse(K_size_array);
var H_array = Convert.FromBase64String(H);
var H_size = H_array.Length;
var H_size_array = BitConverter.GetBytes(H_size);
// reverse zbog toga da ide iz little u big endian - ("normalni")
Array.Reverse(H_size_array);
var sessionIdent_array = Convert.FromBase64String(sessionIdentifier);
var sessionIdent_size = sessionIdent_array.Length;
var sessionIdent_size_array = BitConverter.GetBytes(sessionIdent_size);
// reverse zbog toga da ide iz little u big endian - ("normalni")
Array.Reverse(sessionIdent_size_array);
var A = Convert.ToByte('A');
var B = Convert.ToByte('B');
var C = Convert.ToByte('C');
var D = Convert.ToByte('D');
var E = Convert.ToByte('E');
var F = Convert.ToByte('F');
var KH_array = new List <byte>();
KH_array.AddRange(K_size_array);
KH_array.AddRange(K_array);
KH_array.AddRange(H_size_array);
KH_array.AddRange(H_array);
// 3DES ključ 192b = 24B
// aes256 je 256 bita - 32B
// enkripcija k -> s
forHash.Clear();
forHash.AddRange(KH_array);
forHash.Add(C);
forHash.AddRange(sessionIdent_array);
using (SHA1Managed sha1 = new SHA1Managed())
{
var key_list = sha1.ComputeHash(forHash.ToArray()).ToList();
/*
* If the key length needed is longer than the output of the HASH, the
* key is extended by computing HASH of the concatenation of K and H and
* the entire key so far, and appending the resulting bytes (as many as
* HASH generates) to the key
*/
while (key_list.Count < 24)
{
var temp = new List <byte>();
temp.AddRange(K_array);
temp.AddRange(H_array);
temp.AddRange(key_list);
key_list.AddRange(sha1.ComputeHash(temp.ToArray()));
}
keys.cryCS = key_list.Take(24).ToArray();
}
// enkripcija s -> k
forHash.Clear();
forHash.AddRange(KH_array);
forHash.Add(D);
forHash.AddRange(sessionIdent_array);
using (SHA1Managed sha1 = new SHA1Managed())
{
var key_list = sha1.ComputeHash(forHash.ToArray()).ToList();
/*
* If the key length needed is longer than the output of the HASH, the
* key is extended by computing HASH of the concatenation of K and H and
* the entire key so far, and appending the resulting bytes (as many as
* HASH generates) to the key
*/
while (key_list.Count < 24)
{
var temp = new List <byte>();
temp.AddRange(K_array);
temp.AddRange(H_array);
temp.AddRange(key_list);
key_list.AddRange(sha1.ComputeHash(temp.ToArray()));
}
keys.crySC = key_list.Take(24).ToArray();
}
return(keys);
}
public static EncryptionKeys GenerateEncryptionKeysFor3DES_CBC(string encryptionAl, string macAl, ref EncryptionAlgorithms encryptionAlgorithms, BigInteger K, string H, string sessionIdentifier)
{
// session identifier = H - ostaje isti čak i ako se ključevi promijene (i sam H je tada drugačiji...)
/*
* Inicijalni IV (klijent -> poslužitelj) = hash (K || H || "A" || identifikator_sjednice)
* Inicijalni IV (poslužitelj -> klijent) = hash (K || H || "B" || identifikator_sjednice)
* Kljuc enkripcije (klijent -> poslužitelj) = hash (K || H || "C" || identifikator_sjednice)
* Kljuc enkripcije (poslužitelj -> klijent) = hash (K || H || "D" || identifikator_sjednice)
* MAC kljuc (klijent -> poslužitelj) = hash (K || H || "E" || identifikator_sjednice)
* MAC kljuc (klijent -> poslužitelj) = hash (K || H || "F" || identifikator_sjednice)
*/
EncryptionKeys keys = new EncryptionKeys();
List <byte> forHash = new List <byte>();
var K_array = K.ToByteArrayUnsigned();
var K_size = K_array.Length;
var K_size_array = BitConverter.GetBytes(K_size);
// reverse zbog toga da ide iz little u big endian - ("normalni")
Array.Reverse(K_size_array);
var H_array = Convert.FromBase64String(H);
var H_size = H_array.Length;
var H_size_array = BitConverter.GetBytes(H_size);
// reverse zbog toga da ide iz little u big endian - ("normalni")
Array.Reverse(H_size_array);
var sessionIdent_array = Convert.FromBase64String(sessionIdentifier);
var sessionIdent_size = sessionIdent_array.Length;
var sessionIdent_size_array = BitConverter.GetBytes(sessionIdent_size);
// reverse zbog toga da ide iz little u big endian - ("normalni")
Array.Reverse(sessionIdent_size_array);
var A = Convert.ToByte('A');
var B = Convert.ToByte('B');
var C = Convert.ToByte('C');
var D = Convert.ToByte('D');
var E = Convert.ToByte('E');
var F = Convert.ToByte('F');
var KH_array = new List <byte>();
KH_array.AddRange(K_size_array);
KH_array.AddRange(K_array);
KH_array.AddRange(H_size_array);
KH_array.AddRange(H_array);
// vektor k -> s
forHash.Clear();
forHash.AddRange(KH_array);
forHash.Add(A);
forHash.AddRange(sessionIdent_array);
using (SHA1Managed sha1 = new SHA1Managed())
{
var key_list = sha1.ComputeHash(forHash.ToArray()).ToList();
/*
* If the key length needed is longer than the output of the HASH, the
* key is extended by computing HASH of the concatenation of K and H and
* the entire key so far, and appending the resulting bytes (as many as
* HASH generates) to the key
*/
while (key_list.Count < 8)
{
var temp = new List <byte>();
temp.AddRange(K_array);
temp.AddRange(H_array);
temp.AddRange(key_list);
key_list.AddRange(sha1.ComputeHash(temp.ToArray()));
}
keys.vectorCS = key_list.Take(8).ToArray();
}
// vektor s -> k
forHash.Clear();
forHash.AddRange(KH_array);
forHash.Add(B);
forHash.AddRange(sessionIdent_array);
using (SHA1Managed sha1 = new SHA1Managed())
{
var key_list = sha1.ComputeHash(forHash.ToArray()).ToList();
/*
* If the key length needed is longer than the output of the HASH, the
* key is extended by computing HASH of the concatenation of K and H and
* the entire key so far, and appending the resulting bytes (as many as
* HASH generates) to the key
*/
while (key_list.Count < 8)
{
var temp = new List <byte>();
temp.AddRange(K_array);
temp.AddRange(H_array);
temp.AddRange(key_list);
key_list.AddRange(sha1.ComputeHash(temp.ToArray()));
}
keys.vectorSC = key_list.Take(8).ToArray();
}
switch (encryptionAl)
{
case "3des-cbc":
{
var encryKeys = Generate3DESKeys(K, H, sessionIdentifier);
keys.cryCS = encryKeys.cryCS;
keys.crySC = encryKeys.crySC;
encryptionAlgorithms.encryption = typeof(SSHHelper).GetMethod("Encrypt_Decrypt3DES_CBC");
break;
}
}
switch (macAl)
{
case "hmac-sha1":
{
EncryptionKeys encryKeys = GenerateHMAC_SHA1Keys(K, H, sessionIdentifier);
keys.MACKeyCS = encryKeys.MACKeyCS;
keys.MACKeySC = encryKeys.MACKeySC;
keys.MAClength = encryKeys.MAClength;
encryptionAlgorithms.MAC = typeof(SSHHelper).GetMethod("Compute_hmac_sha1");
break;
}
case "gost28147":
{
EncryptionKeys encryKeys = GenerateGOST28147Keys(K, H, sessionIdentifier);
keys.MACKeyCS = encryKeys.MACKeyCS;
keys.MACKeySC = encryKeys.MACKeySC;
keys.MAClength = encryKeys.MAClength;
encryptionAlgorithms.MAC = typeof(SSHHelper).GetMethod("Compute_gost28147");
break;
}
}
return(keys);
}
