public static byte[] DecryptIGE(byte[] ciphertext, byte[] key, byte[] iv)
{
var iv1 = new byte[iv.Length / 2];
var iv2 = new byte[iv.Length / 2];
Array.Copy(iv, 0, iv1, 0, iv1.Length);
Array.Copy(iv, iv1.Length, iv2, 0, iv2.Length);
AesEngine aes = new AesEngine();
aes.Init(false, key);
byte[] plaintext = new byte[ciphertext.Length];
int blocksCount = ciphertext.Length / 16;
byte[] ciphertextBlock = new byte[16];
byte[] plaintextBlock = new byte[16];
for (int blockIndex = 0; blockIndex < blocksCount; blockIndex++)
{
for (int i = 0; i < 16; i++)
{
ciphertextBlock[i] = (byte)(ciphertext[blockIndex * 16 + i] ^ iv2[i]);
}
aes.ProcessBlock(ciphertextBlock, 0, plaintextBlock, 0);
for (int i = 0; i < 16; i++)
{
plaintextBlock[i] ^= iv1[i];
}
Array.Copy(ciphertext, blockIndex * 16, iv1, 0, 16);
Array.Copy(plaintextBlock, 0, iv2, 0, 16);
Array.Copy(plaintextBlock, 0, plaintext, blockIndex * 16, 16);
}
return(plaintext);
}
public static byte[] EncryptIGE(byte[] originPlaintext, byte[] key, byte[] iv)
{
byte[] plaintext;
using (MemoryStream plaintextBuffer = new MemoryStream(originPlaintext.Length + 40))
{
//using(SHA1 hash = new SHA1Managed()) {
//byte[] hashsum = hash.ComputeHash(originPlaintext);
//plaintextBuffer.Write(hashsum, 0, hashsum.Length);
plaintextBuffer.Write(originPlaintext, 0, originPlaintext.Length);
while (plaintextBuffer.Position % 16 != 0)
{
plaintextBuffer.WriteByte(0); // TODO: random padding
}
plaintext = plaintextBuffer.ToArray();
}
var iv1 = new byte[iv.Length / 2];
var iv2 = new byte[iv.Length / 2];
Array.Copy(iv, 0, iv1, 0, iv1.Length);
Array.Copy(iv, iv1.Length, iv2, 0, iv2.Length);
AesEngine aes = new AesEngine();
aes.Init(true, key);
int blocksCount = plaintext.Length / 16;
byte[] ciphertext = new byte[plaintext.Length];
byte[] ciphertextBlock = new byte[16];
byte[] plaintextBlock = new byte[16];
for (int blockIndex = 0; blockIndex < blocksCount; blockIndex++)
{
Array.Copy(plaintext, 16 * blockIndex, plaintextBlock, 0, 16);
//logger.info("plaintext block: {0} xor {1}", BitConverter.ToString(plaintextBlock).Replace("-", ""), BitConverter.ToString(iv1).Replace("-", ""));
for (int i = 0; i < 16; i++)
{
plaintextBlock[i] ^= iv1[i];
}
//logger.info("xored plaintext: {0}", BitConverter.ToString(plaintextBlock).Replace("-", ""));
aes.ProcessBlock(plaintextBlock, 0, ciphertextBlock, 0);
//logger.info("encrypted plaintext: {0} xor {1}", BitConverter.ToString(ciphertextBlock).Replace("-", ""), BitConverter.ToString(iv2).Replace("-", ""));
for (int i = 0; i < 16; i++)
{
ciphertextBlock[i] ^= iv2[i];
}
//logger.info("xored ciphertext: {0}", BitConverter.ToString(ciphertextBlock).Replace("-", ""));
Array.Copy(ciphertextBlock, 0, iv1, 0, 16);
Array.Copy(plaintext, 16 * blockIndex, iv2, 0, 16);
Array.Copy(ciphertextBlock, 0, ciphertext, blockIndex * 16, 16);
}
return(ciphertext);
}