public static string encrypt(string plaintext, string password, int nBits)
{
var blockSize = 16; // block size fixed at 16 bytes / 128 bits (Nb=4) for AES
if (!(nBits == 128 || nBits == 192 || nBits == 256))
{
return(""); // standard allows 128/192/256 bit keys
}
// note PHP (5) gives us plaintext and password in UTF8 encoding!
// use AES itself to encrypt password to get cipher key (using plain password as source for
// key expansion) - gives us well encrypted key
var nBytes = nBits / 8; // no bytes in key
var pwBytes = new byte[nBytes];
//byte[] password_bs = System.Text.Encoding.UTF8.GetBytes(password);
for (int i = 0; i < nBytes; i++)
{
byte cc = 0;
if (password.Length > i)
{
cc = (byte)password[i];
}
pwBytes[i] = (byte)(cc & 0xff);
}
var bs = AES.keyExpansion(pwBytes);
var key = AES.cipher(pwBytes, bs, false);
//key = array_merge($key, array_slice($key, 0, $nBytes-16)); // expand key to 16/24/32 bytes long
var _tmp = new byte[key.Length + nBytes - 16];
System.Array.Copy(key, _tmp, key.Length);
System.Array.Copy(key, 0, _tmp, key.Length, nBytes - 16);
key = _tmp;
// initialise counter block (NIST SP800-38A §B.2): millisecond time-stamp for nonce in
// 1st 8 bytes, block counter in 2nd 8 bytes
var counterBlock = new byte[16];
long nonce = UnixTool.timestamp(); // timestamp: milliseconds since 1-Jan-1970
var nonceSec = (long)Math.Floor((decimal)nonce / 1000);
var nonceMs = nonce % 1000;
//AESLogger.needLog(true);
AESLogger.add(nonceMs.ToString());
// encode nonce with seconds in 1st 4 bytes, and (repeated) ms part filling 2nd 4 bytes
for (int i = 0; i < 4; i++)
{
counterBlock[i] = ((byte)(AesCtr.urs(nonceSec, (byte)(i * 8)) & 0xff));
}
for (int i = 0; i < 4; i++)
{
counterBlock[i + 4] = (byte)(nonceMs & 0xff);
}
// and convert it to a string to go on the front of the ciphertext
//var ctrTxt = "";
//for (int i=0; i<8; i++) ctrTxt += (char)(counterBlock[i]);
//var allsb = new StringBuilder();
MemoryStream ms = new MemoryStream();
//for (int i = 0; i < 8; i++) allsb.Append((char)(counterBlock[i]));
for (int i = 0; i < 8; i++)
{
ms.WriteByte((counterBlock[i]));
}
AESLogger.traceSingle(counterBlock);
// generate key schedule - an expansion of the key into distinct Key Rounds for each round
var keySchedule = AES.keyExpansion(key);
//print_r($keySchedule);
var blockCount = (int)Math.Ceiling((decimal)plaintext.Length / blockSize);
var ciphertxt = new string[blockCount]; // ciphertext as array of strings
for (var b = 0; b < blockCount; b++)
{
// set counter (block #) in last 8 bytes of counter block (leaving nonce in 1st 8 bytes)
// done in two stages for 32-bit ops: using two words allows us to go past 2^32 blocks (68GB)
for (var c = 0; c < 4; c++)
{
counterBlock[15 - c] = (byte)(AesCtr.urs(b, (byte)(c * 8)) & 0xff);
}
for (var c = 0; c < 4; c++)
{
counterBlock[15 - c - 4] = (byte)(AesCtr.urs((int)(b / 0x100000000), (byte)(c * 8)));
}
var cipherCntr = AES.cipher(counterBlock, keySchedule, false); // -- encrypt counter block --
// block size is reduced on final block
var blockLength = b < blockCount - 1 ? blockSize : (plaintext.Length - 1) % blockSize + 1;
var cipherByte = new byte[blockLength];
//var sb = new StringBuilder();
for (var i = 0; i < blockLength; i++)
{ // -- xor plaintext with ciphered counter byte-by-byte --
cipherByte[i] = (byte)(cipherCntr[i] ^ (byte)(plaintext[b * blockSize + i]));
//转成字符串
//cipherByte[i] = (char)(cipherByte[i]);
//sb.Append((char)(cipherByte[i]));
ms.WriteByte(cipherByte[i]);
}
//$ciphertxt[$b] = implode('', $cipherByte); // escape troublesome characters in ciphertext
//ciphertxt[b] = sb.ToString();
//allsb.Append(sb.ToString());
}
// implode is more efficient than repeated string concatenation
//var ciphertext = ctrTxt . implode('', $ciphertxt);
//$ciphertext = base64_encode($ciphertext);
//byte[] byteArray = System.Text.Encoding.Default.GetBytes(allsb.ToString());
var byteArray = ms.ToArray();
var ciphertext = Convert.ToBase64String(byteArray);
return(ciphertext);
}
/**
* Decrypt a text encrypted by AES in counter mode of operation
*
* @param ciphertext source text to be decrypted
* @param password the password to use to generate a key
* @param nBits number of bits to be used in the key (128, 192, or 256)
* @return decrypted text
*/
public static string decrypt(string ciphertext, string password, int nBits)
{
int blockSize = 16; // block size fixed at 16 bytes / 128 bits (Nb=4) for AES
if (!(nBits == 128 || nBits == 192 || nBits == 256))
{
return(""); // standard allows 128/192/256 bit keys
}
byte[] bs = Convert.FromBase64String(ciphertext);
//$ciphertext = base64_decode($ciphertext);
// use AES to encrypt password (mirroring encrypt routine)
int nBytes = nBits / 8; // no bytes in key
var pwBytes = new byte[nBytes];
//for (int i=0; i<nBytes; i++) pwBytes[i] = ord(substr($password,$i,1)) & 0xff;
for (int i = 0; i < nBytes; i++)
{
byte cc = 0;
if (password.Length > i)
{
cc = (byte)password[i];
}
pwBytes[i] = (byte)(cc & 0xff);
}
var key = AES.cipher(pwBytes, AES.keyExpansion(pwBytes), false);
//$key = array_merge($key, array_slice($key, 0, $nBytes-16)); // expand key to 16/24/32 bytes long
var _tmp = new byte[key.Length + nBytes - 16];
System.Array.Copy(key, _tmp, key.Length);
System.Array.Copy(key, 0, _tmp, key.Length, nBytes - 16);
key = _tmp;
// recover nonce from 1st element of ciphertext
var counterBlock = new byte[16];
//$ctrTxt = substr($ciphertext, 0, 8);
var ctrTxt = new byte[8];
Array.Copy(bs, ctrTxt, 8);
for (int i = 0; i < 8; i++)
{
counterBlock[i] = ctrTxt[i]; // ord(substr($ctrTxt,$i,1));
}
// generate key schedule
var keySchedule = AES.keyExpansion(key);
// separate ciphertext into blocks (skipping past initial 8 bytes)
var nBlocks = (int )Math.Ceiling((decimal )(((double)bs.Length - 8) / blockSize));
var ct = new List <byte[]>();
//for (var b=0; b<nBlocks; b++) ct[b] = substr($ciphertext, 8+$b*$blockSize, 16);
for (var b = 0; b < nBlocks; b++)
{
var startIndex = 8 + b * blockSize;
var size = 16;
//超标
if (startIndex + 16 > bs.Length)
{
size = bs.Length - startIndex;
}
var tmpbs = new byte[size];
//= substr($ciphertext, 8+$b*$blockSize, 16);
Array.Copy(bs, startIndex, tmpbs, 0, size);
ct.Add(tmpbs);
}
//$ciphertext = $ct; // ciphertext is now array of block-length strings
// plaintext will get generated block-by-block into array of block-length strings
//$plaintxt = array();
//StringBuilder sb = new StringBuilder();
byte[] all_bs = new byte[bs.Length - 8];
int counter = 0;
for (int b = 0; b < nBlocks; b++)
{
// set counter (block #) in last 8 bytes of counter block (leaving nonce in 1st 8 bytes)
for (byte c = 0; c < 4; c++)
{
counterBlock[15 - c] = (byte)(AesCtr.urs(b, (byte)(c * 8)) & 0xff);
}
for (int c = 0; c < 4; c++)
{
counterBlock[15 - c - 4] =
//AesCtr::urs(($b+1)/0x100000000-1, $c*8) & 0xff;
(byte)(AesCtr.urs((int)((b + 1) / 0x100000000), (byte)(c * 8)) & 0xff);
}
// (byte)(AesCtr.urs((int)((b + 1) / 0x100000000 - 1), (byte)(c * 8)) & 0xff);
var cipherCntr = AES.cipher(counterBlock, keySchedule, false); // encrypt counter block
//AESLogger.needLog(true);
AESLogger.traceSingle(counterBlock);
AESLogger.add("-----------------" + b.ToString());
//plaintxtByte = array();
for (int i = 0; i < ct[b].Length; i++)
{
// -- xor plaintext with ciphered counter byte-by-byte --
//$plaintxtByte[$i] = $cipherCntr[$i] ^ ord(substr($ciphertext[$b],$i,1));
byte bone = (byte)(cipherCntr[i] ^ ct[b][i]);
//$plaintxtByte[$i] = chr($plaintxtByte[$i]);
//sb.Append((char)bone);
all_bs[counter] = bone;
counter++;
}
}
// join array of blocks into single plaintext string
//$plaintext = implode('',$plaintxt);
//System.Text.UnicodeEncoding converter = new System.Text.UnicodeEncoding();
return(System.Text.Encoding.UTF8.GetString(all_bs));
//return sb.ToString();
}
