| public NextBytes ( int count ) : byte[] | ||
| count | int | Array length. |
| return | byte[] | |
public static void Encrypt(byte[] masterKey, ArraySegment<byte> plaintext, byte[] output, int outputOffset, ArraySegment<byte>? salt = null, uint counter = 1)
{
int ciphertextLength = CONTEXT_BUFFER_LENGTH + plaintext.Count + MAC_LENGTH;
if (output.Length - outputOffset < ciphertextLength) throw new ArgumentOutOfRangeException(nameof(output), $"'{nameof(output)}' array segment is not big enough for the ciphertext");
try
{
_cryptoRandom.NextBytes(_contextBuffer.Value);
Kdf.SP800_108_Ctr.DeriveKey(hmacFactory: _hmacFactory, key: masterKey, label: salt, context: new ArraySegment<byte>(_contextBuffer.Value, 0, CONTEXT_TWEAK_LENGTH), derivedOutput: _sessionKey.Value.AsArraySegment(), counter: counter);
Utils.BlockCopy(_sessionKey.Value, 0, _macKey.Value, 0, MAC_KEY_LENGTH);
Utils.BlockCopy(_sessionKey.Value, MAC_KEY_LENGTH, _encKey.Value, 0, ENC_KEY_LENGTH);
Utils.BlockCopy(_contextBuffer.Value, 0, output, outputOffset, CONTEXT_BUFFER_LENGTH);
Utils.BlockCopy(_contextBuffer.Value, CONTEXT_TWEAK_LENGTH, _counterBuffer.Value, 0, NONCE_LENGTH);
using (var ctrTransform = new Cipher.AesCtrCryptoTransform(key: _encKey.Value, counterBufferSegment: _counterBuffer.Value.AsArraySegment(), aesFactory: _aesFactory))
{
ctrTransform.TransformBlock(inputBuffer: plaintext.Array, inputOffset: plaintext.Offset, inputCount: plaintext.Count, outputBuffer: output, outputOffset: outputOffset + CONTEXT_BUFFER_LENGTH);
}// using aesEncryptor
using (var hmac = _hmacFactory())
{
hmac.Key = _macKey.Value;
hmac.TransformBlock(output, outputOffset + CONTEXT_TWEAK_LENGTH, NONCE_LENGTH + plaintext.Count, null, 0);
hmac.TransformFinalBlock(output, 0, 0);
var fullmac = hmac.HashInner;
Utils.BlockCopy(fullmac, 0, output, outputOffset + ciphertextLength - MAC_LENGTH, MAC_LENGTH);
}// using hmac
}
finally { EtM_CTR.ClearKeyMaterial(); }
}// Encrypt()
public static void Encrypt(byte[] masterKey, ArraySegment<byte> plaintext, byte[] output, int outputOffset, ArraySegment<byte>? salt = null, uint counter = 1)
{
int fullBlockLength = plaintext.Count & (-Cipher.AesConstants.AES_BLOCK_SIZE);
int finalBlockLength = plaintext.Count % Cipher.AesConstants.AES_BLOCK_SIZE;
int paddingLength = Cipher.AesConstants.AES_BLOCK_SIZE - finalBlockLength;
int ciphertextLength = CONTEXT_BUFFER_LENGTH + plaintext.Count + paddingLength + MAC_LENGTH;
if (output.Length - outputOffset < ciphertextLength) throw new ArgumentOutOfRangeException(nameof(output), $"'{nameof(output)}' array segment is not big enough for the ciphertext");
try
{
var iv = _iv.Value;
var contextBuffer = _contextBuffer.Value;
var encKey = _encKey.Value;
var macKey = _macKey.Value;
var sessionKey = _sessionKey.Value;
using (var aes = _aesFactory())
{
EtM_CBC.ValidateAes(aes);
_cryptoRandom.NextBytes(contextBuffer, 0, CONTEXT_BUFFER_LENGTH);
Utils.BlockCopy(contextBuffer, CONTEXT_TWEAK_LENGTH, iv, 0, AES_IV_LENGTH);
Kdf.SP800_108_Ctr.DeriveKey(hmacFactory: _hmacFactory, key: masterKey, label: salt, context: contextBuffer.AsArraySegment(), derivedOutput: sessionKey.AsArraySegment(), counter: counter);
Utils.BlockCopy(sessionKey, 0, macKey, 0, MAC_KEY_LENGTH);
Utils.BlockCopy(sessionKey, MAC_KEY_LENGTH, encKey, 0, ENC_KEY_LENGTH);
Utils.BlockCopy(contextBuffer, 0, output, outputOffset, CONTEXT_BUFFER_LENGTH);
using (var aesEncryptor = aes.CreateEncryptor(encKey, iv))
{
if (fullBlockLength > 0)
aesEncryptor.TransformBlock(inputBuffer: plaintext.Array, inputOffset: plaintext.Offset, inputCount: fullBlockLength, outputBuffer: output, outputOffset: outputOffset + CONTEXT_BUFFER_LENGTH);
var finalBlockBuffer = aesEncryptor.TransformFinalBlock(inputBuffer: plaintext.Array, inputOffset: plaintext.Offset + fullBlockLength, inputCount: finalBlockLength);
Utils.BlockCopy(finalBlockBuffer, 0, output, outputOffset + CONTEXT_BUFFER_LENGTH + fullBlockLength, finalBlockBuffer.Length);
}// using aesEncryptor
}// using aes
using (var hmac = _hmacFactory())
{
hmac.Key = macKey;
hmac.TransformBlock(output, outputOffset + CONTEXT_TWEAK_LENGTH, AES_IV_LENGTH + plaintext.Count + paddingLength, null, 0);
hmac.TransformFinalBlock(output, 0, 0);
var fullmac = hmac.HashInner;
Utils.BlockCopy(fullmac, 0, output, outputOffset + ciphertextLength - MAC_LENGTH, MAC_LENGTH);
}// using hmac
}
finally { EtM_CBC.ClearKeyMaterial(); }
}// Encrypt()
}// ClearKeyMaterial()
public static void Encrypt(byte[] masterKey, ArraySegment<byte> plaintext, byte[] output, int outputOffset, ArraySegment<byte>? salt = null, uint counter = 1)
{
int ciphertextLength = CONTEXT_BUFFER_LENGTH + plaintext.Count + MAC_LENGTH;
if (output.Length - outputOffset < ciphertextLength) throw new ArgumentOutOfRangeException(nameof(output), $"'{nameof(output)}' array segment is not big enough for the ciphertext");
var counterBuffer = new byte[Cipher.AesConstants.AES_BLOCK_SIZE];
var contextBuffer = new byte[CONTEXT_BUFFER_LENGTH];
var encKey = new byte[ENC_KEY_LENGTH];
var macKey = new byte[MAC_KEY_LENGTH];
var sessionKey = new byte[HMAC_LENGTH];
try
{
_cryptoRandom.NextBytes(contextBuffer, 0, CONTEXT_BUFFER_LENGTH);
Kdf.SP800_108_Ctr.DeriveKey(hmacFactory: _hmacFactory, key: masterKey, label: salt, context: new ArraySegment<byte>(contextBuffer, 0, CONTEXT_TWEAK_LENGTH), derivedOutput: sessionKey.AsArraySegment(), counter: counter);
//Utils.BlockCopy(sessionKey, 0, macKey, 0, MAC_KEY_LENGTH);
for (int i = 0; i < macKey.Length; ++i) macKey[i] = sessionKey[i];
//Utils.BlockCopy(sessionKey, MAC_KEY_LENGTH, encKey, 0, ENC_KEY_LENGTH);
for (int i = 0; i < encKey.Length; ++i) encKey[i] = sessionKey[MAC_KEY_LENGTH + i];
//Utils.BlockCopy(contextBuffer, 0, output, outputOffset, CONTEXT_BUFFER_LENGTH);
for (int i = 0; i < contextBuffer.Length; ++i) output[outputOffset + i] = contextBuffer[i];
//Utils.BlockCopy(contextBuffer, CONTEXT_TWEAK_LENGTH, counterBuffer, 0, NONCE_LENGTH);
for (int i = 0; i < NONCE_LENGTH; ++i) counterBuffer[i] = contextBuffer[CONTEXT_TWEAK_LENGTH + i];
using (var ctrTransform = new Cipher.AesCtrCryptoTransform(key: encKey, counterBufferSegment: counterBuffer.AsArraySegment(), aesFactory: _aesFactory))
{
ctrTransform.TransformBlock(inputBuffer: plaintext.Array, inputOffset: plaintext.Offset, inputCount: plaintext.Count, outputBuffer: output, outputOffset: outputOffset + CONTEXT_BUFFER_LENGTH);
}// using aesEncryptor
using (var hmac = _hmacFactory())
{
hmac.Key = macKey;
hmac.TransformBlock(output, outputOffset + CONTEXT_TWEAK_LENGTH, NONCE_LENGTH + plaintext.Count, null, 0);
hmac.TransformFinalBlock(output, 0, 0);
var fullmac = hmac.HashInner;
//Utils.BlockCopy(fullmac, 0, output, outputOffset + ciphertextLength - MAC_LENGTH, MAC_LENGTH);
for (int i = 0; i < MAC_LENGTH; ++i) output[outputOffset + ciphertextLength - MAC_LENGTH + i] = fullmac[i];
}// using hmac
}
finally { EtM_CTR.ClearKeyMaterial(encKey, macKey, sessionKey); }
}// Encrypt()
