public override byte [] ComputeHash(byte [] buffer)
{
//TODO this isnt working on SP
//IntPtr prov = OpenNETCF.Security.Cryptography.NativeMethods.Context.AcquireContext();
//byte [] baKey = (byte []) key.Clone();
//reversed below
//IntPtr ipKey = OpenNETCF.Security.Cryptography.NativeMethods.Key.ImportSessionKey(prov, Calg.TRIP_DES, baKey, true);
//hash = OpenNETCF.Security.Cryptography.NativeMethods.Hash.ComputeKeyedHash(prov, CalgHash.MAC, buffer, ipKey);
//OpenNETCF.Security.Cryptography.NativeMethods.Key.DestroyKey(ipKey);
//OpenNETCF.Security.Cryptography.NativeMethods.Context.ReleaseContext(prov);
//return hash;
//http://www.itl.nist.gov/fipspubs/fip81.htm - Appendix F
int blocks = buffer.Length / 8;
int rem = buffer.Length % 8;
if (rem != 0)
{
blocks = blocks + 1;
}
byte [] padBuffer = new byte[blocks * 8];
Array.Copy(buffer, 0, padBuffer, 0, buffer.Length);
//this leaves 0's at the end
TripleDESCryptoServiceProvider tdcsp = new TripleDESCryptoServiceProvider();
tdcsp.Key = this.key;
tdcsp.IV = new byte[8];
TripleDesNoPadding tdnp = new TripleDesNoPadding(tdcsp);
byte [] cipher = tdnp.Encrypt(padBuffer);
//#if NET_1_0 - from Mono
// add an empty (zeros) block for MAC padding
//byte[] emptyBlock = new byte [blockSize];
//result = enc.TransformFinalBlock (emptyBlock, 0, blockSize);
hash = new byte[8];
Array.Copy(cipher, cipher.Length - 8, hash, 0, 8);
return(hash);
}
public static void Protect(byte[] userData, MemoryProtectionScope scope)
{
//IntPtr ip = Mem.CryptMemAlloc(memLen);
//if(ip == IntPtr.Zero)
// throw new Exception("memory not allocated");
//Marshal.Copy(userData, 0, ip, userData.Length);
int memLen = userData.Length;
if (memLen % 16 != 0)
{
throw new Exception("message length must be divisible by 16");
}
byte [] randKey;
if (scope == MemoryProtectionScope.SameProcess)
{
randKey = Cipher.UnprotectData(protectedKey);
}
else //sameLong, crossProcess
{
randKey = Cipher.UnprotectData(protectedKeyCross);
}
DESCryptoServiceProvider dcsp = new DESCryptoServiceProvider();
dcsp.Key = randKey;
TripleDesNoPadding tdnp = new TripleDesNoPadding(dcsp);
byte [] cipher = tdnp.Encrypt(userData);
for (int i = 0; i < cipher.Length; i++)
{
userData[i] = cipher[i];
}
//userData = Cipher.ProtectData(userData);
//byte [] retBa = Cipher.ProtectData(userData);
//Array.Clear(userData, 0, userData.Length);
//userData = retBa;
}
public static void Unprotect(byte[] encryptedData, MemoryProtectionScope scope)
{
//if(ip == IntPtr.Zero)
// throw new Exception("memory not re-allocated");
//Mem.CryptMemFree(ip);
int memLen = encryptedData.Length;
if (memLen % 16 != 0)
{
throw new Exception("message length must be divisible by 16");
}
byte [] randKey;
if (scope == MemoryProtectionScope.SameProcess)
{
randKey = Cipher.UnprotectData(protectedKey);
}
else //sameLong, crossProcess
{
randKey = Cipher.UnprotectData(protectedKeyCross);
}
DESCryptoServiceProvider dcsp = new DESCryptoServiceProvider();
dcsp.Key = randKey;
TripleDesNoPadding tdnp = new TripleDesNoPadding(dcsp);
byte [] clear = tdnp.Decrypt(encryptedData);
for (int i = 0; i < clear.Length; i++)
{
encryptedData[i] = clear[i];
}
//encryptedData = Cipher.UnprotectData(encryptedData);
//byte [] retBa = Cipher.UnprotectData(encryptedData);
//Array.Clear(encryptedData, 0, encryptedData.Length);
//encryptedData = retBa;
}
