| public static ConstantTimeEqual ( Array x, Array y ) : bool | ||
| x | Array | |
| y | Array | |
| 리턴 | bool | |
}// Decrypt()
public static byte[] Decrypt(byte[] masterKey, ArraySegment<byte> ciphertext, ArraySegment<byte>? salt = null, uint counter = 1)
{
int cipherLength = ciphertext.Count - CONTEXT_BUFFER_LENGTH - MAC_LENGTH;
if (cipherLength < Cipher.AesConstants.AES_BLOCK_SIZE) return null;
try
{
Kdf.SP800_108_Ctr.DeriveKey(hmacFactory: _hmacFactory, key: masterKey, label: salt, context: new ArraySegment<byte>(ciphertext.Array, ciphertext.Offset, CONTEXT_BUFFER_LENGTH), derivedOutput: _sessionKey.Value.AsArraySegment(), counter: counter);
Utils.BlockCopy(_sessionKey.Value, 0, _macKey.Value, 0, MAC_KEY_LENGTH);
using (var hmac = _hmacFactory())
{
hmac.Key = _macKey.Value;
hmac.TransformBlock(ciphertext.Array, ciphertext.Offset + CONTEXT_TWEAK_LENGTH, AES_IV_LENGTH + cipherLength, null, 0);
hmac.TransformFinalBlock(ciphertext.Array, 0, 0);
var fullmacActual = hmac.HashInner;
if (!Utils.ConstantTimeEqual(fullmacActual, 0, ciphertext.Array, ciphertext.Offset + ciphertext.Count - MAC_LENGTH, MAC_LENGTH)) return null;
}// using hmac
Utils.BlockCopy(ciphertext.Array, ciphertext.Offset + CONTEXT_TWEAK_LENGTH, _iv.Value, 0, AES_IV_LENGTH);
Utils.BlockCopy(_sessionKey.Value, MAC_KEY_LENGTH, _encKey.Value, 0, ENC_KEY_LENGTH);
using (var aes = _aesFactory())
{
EtM_CBC.ValidateAes(aes);
using (var aesDecryptor = aes.CreateDecryptor(_encKey.Value, _iv.Value))
{
return aesDecryptor.TransformFinalBlock(ciphertext.Array, ciphertext.Offset + CONTEXT_BUFFER_LENGTH, cipherLength);
}// using aesDecryptor
}// using aes
}
finally { EtM_CBC.ClearKeyMaterial(); }
}// Decrypt()
}// Encrypt()
public static void Decrypt(byte[] masterKey, ArraySegment<byte> ciphertext, ref ArraySegment<byte>? outputSegment, ArraySegment<byte>? salt = null, uint counter = 1)
{
int cipherLength = ciphertext.Count - CONTEXT_BUFFER_LENGTH - MAC_LENGTH;
if (cipherLength < 0) { outputSegment = null; return; }
try
{
Kdf.SP800_108_Ctr.DeriveKey(hmacFactory: _hmacFactory, key: masterKey, label: salt, context: new ArraySegment<byte>(ciphertext.Array, ciphertext.Offset, CONTEXT_TWEAK_LENGTH), derivedOutput: new ArraySegment<byte>(_sessionKey.Value), counter: counter);
Utils.BlockCopy(_sessionKey.Value, 0, _macKey.Value, 0, MAC_KEY_LENGTH);
using (var hmac = _hmacFactory())
{
hmac.Key = _macKey.Value;
hmac.TransformBlock(ciphertext.Array, ciphertext.Offset + CONTEXT_TWEAK_LENGTH, NONCE_LENGTH + cipherLength, null, 0);
hmac.TransformFinalBlock(ciphertext.Array, 0, 0);
var fullmacActual = hmac.HashInner;
if (!Utils.ConstantTimeEqual(fullmacActual, 0, ciphertext.Array, ciphertext.Offset + ciphertext.Count - MAC_LENGTH, MAC_LENGTH)) { outputSegment = null; return; };
}// using hmac
if (outputSegment == null) outputSegment = (new byte[cipherLength]).AsNullableArraySegment();
Utils.BlockCopy(ciphertext.Array, ciphertext.Offset + CONTEXT_TWEAK_LENGTH, _counterBuffer.Value, 0, NONCE_LENGTH);
Utils.BlockCopy(_sessionKey.Value, MAC_KEY_LENGTH, _encKey.Value, 0, ENC_KEY_LENGTH);
using (var ctrTransform = new Cipher.AesCtrCryptoTransform(key: _encKey.Value, counterBufferSegment: _counterBuffer.Value.AsArraySegment(), aesFactory: _aesFactory))
{
ctrTransform.TransformBlock(inputBuffer: ciphertext.Array, inputOffset: ciphertext.Offset + CONTEXT_BUFFER_LENGTH, inputCount: cipherLength, outputBuffer: outputSegment.GetValueOrDefault().Array, outputOffset: outputSegment.GetValueOrDefault().Offset);
}// using aesDecryptor
}
finally { EtM_CTR.ClearKeyMaterial(); }
}// Decrypt()
}// Decrypt()
public static bool Authenticate(byte[] masterKey, ArraySegment<byte> ciphertext, ArraySegment<byte>? salt = null, uint counter = 1)
{
int cipherLength = ciphertext.Count - CONTEXT_BUFFER_LENGTH - MAC_LENGTH;
if (cipherLength < 0) return false;
var encKey = new byte[ENC_KEY_LENGTH];
var macKey = new byte[MAC_KEY_LENGTH];
var sessionKey = new byte[HMAC_LENGTH];
try
{
var ciphertextArray = ciphertext.Array;
var ciphertextOffset = ciphertext.Offset;
Kdf.SP800_108_Ctr.DeriveKey(hmacFactory: _hmacFactory, key: masterKey, label: salt, context: new ArraySegment<byte>(ciphertextArray, ciphertextOffset, 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];
using (var hmac = _hmacFactory())
{
hmac.Key = macKey;
hmac.TransformBlock(ciphertextArray, ciphertextOffset + CONTEXT_TWEAK_LENGTH, NONCE_LENGTH + cipherLength, null, 0);
hmac.TransformFinalBlock(ciphertextArray, 0, 0);
var fullmacActual = hmac.HashInner;
if (!Utils.ConstantTimeEqual(fullmacActual, 0, ciphertextArray, ciphertextOffset + ciphertext.Count - MAC_LENGTH, MAC_LENGTH)) return false;
}// using hmac
return true;
}
finally { EtM_CTR.ClearKeyMaterial(encKey, macKey, sessionKey); }
}// Authenticate()
}// Encrypt()
public static void Decrypt(byte[] masterKey, ArraySegment<byte> ciphertext, ref ArraySegment<byte>? outputSegment, ArraySegment<byte>? salt = null, uint counter = 1)
{
int cipherLength = ciphertext.Count - CONTEXT_BUFFER_LENGTH - MAC_LENGTH;
if (cipherLength < Cipher.AesConstants.AES_BLOCK_SIZE) { outputSegment = null; return; }
int fullBlockLength = cipherLength - AES_IV_LENGTH;
byte[] finalBlock = null;
try
{
var iv = _iv.Value;
var encKey = _encKey.Value;
var macKey = _macKey.Value;
var sessionKey = _sessionKey.Value;
Kdf.SP800_108_Ctr.DeriveKey(hmacFactory: _hmacFactory, key: masterKey, label: salt, context: new ArraySegment<byte>(ciphertext.Array, ciphertext.Offset, CONTEXT_BUFFER_LENGTH), derivedOutput: sessionKey.AsArraySegment(), counter: counter);
Utils.BlockCopy(sessionKey, 0, macKey, 0, MAC_KEY_LENGTH);
using (var hmac = _hmacFactory())
{
hmac.Key = macKey;
hmac.TransformBlock(ciphertext.Array, ciphertext.Offset + CONTEXT_TWEAK_LENGTH, AES_IV_LENGTH + cipherLength, null, 0);
hmac.TransformFinalBlock(ciphertext.Array, 0, 0);
var fullmacActual = hmac.HashInner;
if (!Utils.ConstantTimeEqual(fullmacActual, 0, ciphertext.Array, ciphertext.Offset + ciphertext.Count - MAC_LENGTH, MAC_LENGTH)) { outputSegment = null; return; };
}// using hmac
Utils.BlockCopy(ciphertext.Array, ciphertext.Offset + CONTEXT_TWEAK_LENGTH, iv, 0, AES_IV_LENGTH);
Utils.BlockCopy(sessionKey, MAC_KEY_LENGTH, encKey, 0, ENC_KEY_LENGTH);
using (var aes = _aesFactory())
{
EtM_CBC.ValidateAes(aes);
using (var aesDecryptor = aes.CreateDecryptor(encKey, iv))
{
int fullBlockTransformed = 0;
if (fullBlockLength > 0)
fullBlockTransformed = aesDecryptor.TransformBlock(inputBuffer: ciphertext.Array, inputOffset: ciphertext.Offset + CONTEXT_BUFFER_LENGTH, inputCount: fullBlockLength, outputBuffer: outputSegment.Value.Array, outputOffset: outputSegment.Value.Offset);
finalBlock = aesDecryptor.TransformFinalBlock(ciphertext.Array, ciphertext.Offset + CONTEXT_BUFFER_LENGTH + fullBlockLength, cipherLength - fullBlockLength);
Utils.BlockCopy(finalBlock, 0, outputSegment.Value.Array, outputSegment.Value.Offset + fullBlockTransformed, finalBlock.Length);
outputSegment = new ArraySegment<byte>?(new ArraySegment<byte>(outputSegment.Value.Array, outputSegment.Value.Offset, fullBlockTransformed + finalBlock.Length));
}// using aesDecryptor
}// using aes
}
finally
{
EtM_CBC.ClearKeyMaterial();
if (finalBlock != null) Array.Clear(finalBlock, 0, finalBlock.Length);
}
}// Decrypt()
}// Encrypt()
public static void Decrypt(byte[] masterKey, ArraySegment<byte> ciphertext, ref ArraySegment<byte>? outputSegment, ArraySegment<byte>? salt = null, uint counter = 1)
{
int cipherLength = ciphertext.Count - CONTEXT_BUFFER_LENGTH - MAC_LENGTH;
if (cipherLength < 0) { outputSegment = null; return; }
var counterBuffer = new byte[Cipher.AesConstants.AES_BLOCK_SIZE];
var encKey = new byte[ENC_KEY_LENGTH];
var macKey = new byte[MAC_KEY_LENGTH];
var sessionKey = new byte[HMAC_LENGTH];
try
{
var ciphertextArray = ciphertext.Array;
var ciphertextOffset = ciphertext.Offset;
Kdf.SP800_108_Ctr.DeriveKey(hmacFactory: _hmacFactory, key: masterKey, label: salt, context: new ArraySegment<byte>(ciphertextArray, ciphertextOffset, 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];
using (var hmac = _hmacFactory())
{
hmac.Key = macKey;
hmac.TransformBlock(ciphertextArray, ciphertextOffset + CONTEXT_TWEAK_LENGTH, NONCE_LENGTH + cipherLength, null, 0);
hmac.TransformFinalBlock(ciphertextArray, 0, 0);
var fullmacActual = hmac.HashInner;
if (!Utils.ConstantTimeEqual(fullmacActual, 0, ciphertextArray, ciphertextOffset + ciphertext.Count - MAC_LENGTH, MAC_LENGTH)) { outputSegment = null; return; };
}// using hmac
if (outputSegment == null) outputSegment = (new byte[cipherLength]).AsNullableArraySegment();
//Utils.BlockCopy(ciphertext.Array, ciphertext.Offset + CONTEXT_TWEAK_LENGTH, counterBuffer, 0, NONCE_LENGTH);
for (int i = 0; i < NONCE_LENGTH; ++i) counterBuffer[i] = ciphertextArray[ciphertextOffset + CONTEXT_TWEAK_LENGTH + 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];
using (var ctrTransform = new Cipher.AesCtrCryptoTransform(key: encKey, counterBufferSegment: counterBuffer.AsArraySegment(), aesFactory: _aesFactory))
{
ctrTransform.TransformBlock(inputBuffer: ciphertextArray, inputOffset: ciphertextOffset + CONTEXT_BUFFER_LENGTH, inputCount: cipherLength, outputBuffer: outputSegment.GetValueOrDefault().Array, outputOffset: outputSegment.GetValueOrDefault().Offset);
}// using aesDecryptor
}
finally { EtM_CTR.ClearKeyMaterial(encKey, macKey, sessionKey); }
}// Decrypt()
}// Decrypt()
public static bool Authenticate(byte[] masterKey, ArraySegment<byte> ciphertext, ArraySegment<byte>? salt = null, uint counter = 1)
{
int cipherLength = ciphertext.Count - CONTEXT_BUFFER_LENGTH - MAC_LENGTH;
if (cipherLength < 0) return false;
try
{
Kdf.SP800_108_Ctr.DeriveKey(hmacFactory: _hmacFactory, key: masterKey, label: salt, context: new ArraySegment<byte>(ciphertext.Array, ciphertext.Offset, CONTEXT_TWEAK_LENGTH), derivedOutput: _sessionKey.Value.AsArraySegment(), counter: counter);
Utils.BlockCopy(_sessionKey.Value, 0, _macKey.Value, 0, MAC_KEY_LENGTH);
using (var hmac = _hmacFactory())
{
hmac.Key = _macKey.Value;
hmac.TransformBlock(ciphertext.Array, ciphertext.Offset + CONTEXT_TWEAK_LENGTH, NONCE_LENGTH + cipherLength, null, 0);
hmac.TransformFinalBlock(ciphertext.Array, 0, 0);
var fullmacActual = hmac.HashInner;
if (!Utils.ConstantTimeEqual(fullmacActual, 0, ciphertext.Array, ciphertext.Offset + ciphertext.Count - MAC_LENGTH, MAC_LENGTH)) return false;
}// using hmac
return true;
}
finally { EtM_CTR.ClearKeyMaterial(); }
}// Authenticate()
