public void GenerateKeyStream(byte[] key, byte[] iv, byte[] output)
{
if (output.Length % BLOCK_SIZE != 0)
{
throw new Exception("Output buffer size must be aligned to BLOCK_SIZE");
}
var keyHandle = default(GCHandle);
var ivHandle = default(GCHandle);
var inputHandle = default(GCHandle);
var outputHandle = default(GCHandle);
try
{
var inputBlock = new byte[BLOCK_SIZE];
keyHandle = GCHandle.Alloc(key, GCHandleType.Pinned);
ivHandle = GCHandle.Alloc(iv, GCHandleType.Pinned);
inputHandle = GCHandle.Alloc(inputBlock, GCHandleType.Pinned);
outputHandle = GCHandle.Alloc(output, GCHandleType.Pinned);
if (OpenSsl.EVP_EncryptInit_ex(_ctx, OpenSsl.EVP_aes_128_ctr(), IntPtr.Zero,
keyHandle.AddrOfPinnedObject(), ivHandle.AddrOfPinnedObject()) != 1)
{
throw new Exception($"Cannot initialize AES: {OpenSsl.GetLastError()}");
}
int outputOffset = 0;
while (outputOffset < output.Length)
{
int outputLength = 0;
if (OpenSsl.EVP_EncryptUpdate(_ctx,
IntPtr.Add(outputHandle.AddrOfPinnedObject(), outputOffset), ref outputLength,
inputHandle.AddrOfPinnedObject(), BLOCK_SIZE) != 1)
{
throw new Exception($"Cannot encode AES: {OpenSsl.GetLastError()}");
}
outputOffset += outputLength;
}
}
finally
{
if (keyHandle.IsAllocated)
{
keyHandle.Free();
}
if (ivHandle.IsAllocated)
{
ivHandle.Free();
}
if (inputHandle.IsAllocated)
{
inputHandle.Free();
}
if (outputHandle.IsAllocated)
{
outputHandle.Free();
}
}
}
public void GenerateSessionKey(
byte[] masterKey,
byte[] masterSalt,
byte[] sessionKey,
byte[] sessionSalt,
byte[] sessionAuth
)
{
var keyHandle = default(GCHandle);
var ivHandle = default(GCHandle);
var inputHandle = default(GCHandle);
var sessionKeyHandle = default(GCHandle);
var sessionSaltHandle = default(GCHandle);
var sessionAuthHandle = default(GCHandle);
try
{
var inputBlock = new byte[BLOCK_SIZE];
var sessionIv = new byte[BLOCK_SIZE];
keyHandle = GCHandle.Alloc(masterKey, GCHandleType.Pinned);
ivHandle = GCHandle.Alloc(sessionIv, GCHandleType.Pinned);
inputHandle = GCHandle.Alloc(inputBlock, GCHandleType.Pinned);
sessionKeyHandle = GCHandle.Alloc(sessionKey, GCHandleType.Pinned);
sessionSaltHandle = GCHandle.Alloc(sessionSalt, GCHandleType.Pinned);
sessionAuthHandle = GCHandle.Alloc(sessionAuth, GCHandleType.Pinned);
Array.Copy(masterSalt, sessionIv, masterSalt.Length);
if (OpenSsl.EVP_EncryptInit_ex(_ctx, OpenSsl.EVP_aes_128_ctr(), IntPtr.Zero,
keyHandle.AddrOfPinnedObject(), ivHandle.AddrOfPinnedObject()) != 1)
{
throw new Exception($"Cannot initialize AES: {OpenSsl.GetLastError()}");
}
int outputLength = 0;
if (OpenSsl.EVP_EncryptUpdate(_ctx,
sessionKeyHandle.AddrOfPinnedObject(), ref outputLength,
inputHandle.AddrOfPinnedObject(), BLOCK_SIZE) != 1)
{
throw new Exception($"Cannot encode AES: {OpenSsl.GetLastError()}");
}
sessionIv[7] ^= 0x02;
if (OpenSsl.EVP_EncryptInit_ex(_ctx, OpenSsl.EVP_aes_128_ctr(), IntPtr.Zero,
keyHandle.AddrOfPinnedObject(), ivHandle.AddrOfPinnedObject()) != 1)
{
throw new Exception($"Cannot initialize AES: {OpenSsl.GetLastError()}");
}
outputLength = 0;
if (OpenSsl.EVP_EncryptUpdate(_ctx,
sessionSaltHandle.AddrOfPinnedObject(), ref outputLength,
inputHandle.AddrOfPinnedObject(), BLOCK_SIZE) != 1)
{
throw new Exception($"Cannot encode AES: {OpenSsl.GetLastError()}");
}
sessionIv[7] ^= 0x03;
if (OpenSsl.EVP_EncryptInit_ex(_ctx, OpenSsl.EVP_aes_128_ctr(), IntPtr.Zero,
keyHandle.AddrOfPinnedObject(), ivHandle.AddrOfPinnedObject()) != 1)
{
throw new Exception($"Cannot initialize AES: {OpenSsl.GetLastError()}");
}
int outputOffset = 0;
while (outputOffset < sessionAuth.Length)
{
outputLength = 0;
if (OpenSsl.EVP_EncryptUpdate(_ctx,
IntPtr.Add(sessionAuthHandle.AddrOfPinnedObject(), outputOffset), ref outputLength,
inputHandle.AddrOfPinnedObject(), BLOCK_SIZE) != 1)
{
throw new Exception($"Cannot encode AES: {OpenSsl.GetLastError()}");
}
outputOffset += outputLength;
}
}
finally
{
if (keyHandle.IsAllocated)
{
keyHandle.Free();
}
if (ivHandle.IsAllocated)
{
ivHandle.Free();
}
if (inputHandle.IsAllocated)
{
inputHandle.Free();
}
if (sessionKeyHandle.IsAllocated)
{
sessionKeyHandle.Free();
}
if (sessionSaltHandle.IsAllocated)
{
sessionSaltHandle.Free();
}
if (sessionAuthHandle.IsAllocated)
{
sessionAuthHandle.Free();
}
}
}
