public byte [] EncryptValue(byte [] key)
{
//http://www.w3.org/TR/2002/REC-xmlenc-core-20021210/Overview.html
byte[] bs1 = _tdcsp.Key;
SHA1CryptoServiceProvider sha1Csp = new SHA1CryptoServiceProvider();
byte[] bs2 = sha1Csp.ComputeHash(key);
RNGCryptoServiceProvider rNGCryptoServiceProvider = new RNGCryptoServiceProvider();
byte[] bs3 = new byte[8];
rNGCryptoServiceProvider.GetBytes(bs3);
byte[] bs4 = new byte[(int)key.Length + 8];
_tdcsp.IV = bs3;
Buffer.BlockCopy(key, 0, bs4, 0, (int)key.Length);
Buffer.BlockCopy(bs2, 0, bs4, (int)key.Length, 8);
TripleDesNoPadding tdnp1 = new TripleDesNoPadding(_tdcsp);
byte [] bs5 = tdnp1.Encrypt(bs4);
byte[] bs6 = new byte[(int)bs3.Length + (int)bs5.Length];
Buffer.BlockCopy(bs3, 0, bs6, 0, (int)bs3.Length);
Buffer.BlockCopy(bs5, 0, bs6, (int)bs3.Length, (int)bs5.Length);
Array.Reverse(bs6, 0, bs6.Length);
_tdcsp.Key = bs1;
_tdcsp.IV = kwIv;
TripleDesNoPadding tdnp2 = new TripleDesNoPadding(_tdcsp);
byte [] cipher = tdnp2.Encrypt(bs6);
return(cipher);
}
public override byte [] EncryptValue(byte [] key)
{
//http://www.w3.org/TR/2002/REC-xmlenc-core-20021210/Overview.html
byte[] bs1 = _tdcsp.Key;
SHA1CryptoServiceProvider sha1Csp = new SHA1CryptoServiceProvider();
byte[] bs2 = sha1Csp.ComputeHash(key);
RNGCryptoServiceProvider rNGCryptoServiceProvider = new RNGCryptoServiceProvider();
byte[] bs3 = new byte[8];
rNGCryptoServiceProvider.GetBytes(bs3);
byte[] bs4 = new byte[(int)key.Length + 8];
_tdcsp.IV = bs3;
Buffer.BlockCopy(key, 0, bs4, 0, (int)key.Length);
Buffer.BlockCopy(bs2, 0, bs4, (int)key.Length, 8);
TripleDesNoPadding tdnp1 = new TripleDesNoPadding(_tdcsp);
byte [] bs5 = tdnp1.Encrypt(bs4);
byte[] bs6 = new byte[(int)bs3.Length + (int)bs5.Length];
Buffer.BlockCopy(bs3, 0, bs6, 0, (int)bs3.Length);
Buffer.BlockCopy(bs5, 0, bs6, (int)bs3.Length, (int)bs5.Length);
Array.Reverse(bs6, 0, bs6.Length);
_tdcsp.Key = bs1;
_tdcsp.IV = kwIv;
TripleDesNoPadding tdnp2 = new TripleDesNoPadding(_tdcsp);
byte [] cipher = tdnp2.Encrypt(bs6);
return cipher;
}
public byte [] DecryptValue(byte [] keyWrap)
{
//1. Check if the length of the cipher text is reasonable given the key type.
//It must be 40 bytes for a 168 bit key and either 32, 40, or 48 bytes for a 128, 192, or 256 bit key.
//If the length is not supported or inconsistent with the algorithm for which the key is intended, return error.
if (keyWrap.Length < 40)
{
throw new Exception("kw-tripledes must be 40 bytes for TripleDES key");
}
//2. Decrypt the cipher text with TRIPLEDES in CBC mode using the KEK and an initialization vector (IV) of 0x4adda22c79e82105. Call the output TEMP3.
_tdcsp.IV = kwIv;
TripleDesNoPadding tdnp = new TripleDesNoPadding(_tdcsp);
byte [] temp3 = tdnp.Decrypt(keyWrap);
//3. Reverse the order of the octets in TEMP3 and call the result TEMP2.
byte [] temp2 = (byte [])temp3.Clone();
Array.Reverse(temp2, 0, temp2.Length);
//4. Decompose TEMP2 into IV, the first 8 octets, and TEMP1, the remaining octets.
byte [] temp1iv = new byte[_tdcsp.IV.Length];
Array.Copy(temp2, 0, temp1iv, 0, temp1iv.Length);
byte [] temp1 = new byte [temp2.Length - temp1iv.Length];
Array.Copy(temp2, temp1iv.Length, temp1, 0, temp1.Length);
//5. Decrypt TEMP1 using TRIPLEDES in CBC mode using the KEK and the IV found in the previous step. Call the result WKCKS.
_tdcsp.IV = temp1iv;
byte [] WKCKS = tdnp.Decrypt(temp1);
//6. Decompose WKCKS. CKS is the last 8 octets and WK, the wrapped key, are those octets before the CKS.
byte [] CKS = new byte[8];
byte [] WK = new byte[WKCKS.Length - 8];
Array.Copy(WKCKS, WKCKS.Length - 8, CKS, 0, 8);
Array.Copy(WKCKS, 0, WK, 0, WKCKS.Length - 8);
//7. Calculate a CMS key checksum (section 5.6.1) over the WK and compare with the CKS extracted in the above step. If they are not equal, return error.
SHA1CryptoServiceProvider sha1 = new SHA1CryptoServiceProvider();
byte [] CMS = sha1.ComputeHash(WK);
//check hash
for (int i = 0; i < CKS.Length; i++)
{
if (CKS[i] != CMS[i])
{
throw new Exception("KeyWrap CheckSum failed");
}
}
//8. WK is the wrapped key, now extracted for use in data decryption.
return(WK);
}
public override byte [] DecryptValue(byte [] keyWrap)
{
//1. Check if the length of the cipher text is reasonable given the key type.
//It must be 40 bytes for a 168 bit key and either 32, 40, or 48 bytes for a 128, 192, or 256 bit key.
//If the length is not supported or inconsistent with the algorithm for which the key is intended, return error.
if(keyWrap.Length < 40)
{
throw new Exception("kw-tripledes must be 40 bytes for TripleDES key");
}
//2. Decrypt the cipher text with TRIPLEDES in CBC mode using the KEK and an initialization vector (IV) of 0x4adda22c79e82105. Call the output TEMP3.
_tdcsp.IV = kwIv;
TripleDesNoPadding tdnp = new TripleDesNoPadding(_tdcsp);
byte [] temp3 = tdnp.Decrypt(keyWrap);
//3. Reverse the order of the octets in TEMP3 and call the result TEMP2.
byte [] temp2 = (byte []) temp3.Clone();
Array.Reverse(temp2, 0, temp2.Length);
//4. Decompose TEMP2 into IV, the first 8 octets, and TEMP1, the remaining octets.
byte [] temp1iv = new byte[_tdcsp.IV.Length];
Array.Copy(temp2, 0, temp1iv, 0, temp1iv.Length);
byte [] temp1 = new byte [temp2.Length - temp1iv.Length];
Array.Copy(temp2, temp1iv.Length, temp1, 0, temp1.Length);
//5. Decrypt TEMP1 using TRIPLEDES in CBC mode using the KEK and the IV found in the previous step. Call the result WKCKS.
_tdcsp.IV = temp1iv;
byte [] WKCKS = tdnp.Decrypt(temp1);
//6. Decompose WKCKS. CKS is the last 8 octets and WK, the wrapped key, are those octets before the CKS.
byte [] CKS = new byte[8];
byte [] WK = new byte[WKCKS.Length - 8];
Array.Copy(WKCKS, WKCKS.Length - 8, CKS, 0, 8);
Array.Copy(WKCKS, 0, WK, 0, WKCKS.Length - 8);
//7. Calculate a CMS key checksum (section 5.6.1) over the WK and compare with the CKS extracted in the above step. If they are not equal, return error.
SHA1CryptoServiceProvider sha1 = new SHA1CryptoServiceProvider();
byte [] CMS = sha1.ComputeHash(WK);
//check hash
for(int i=0; i<CKS.Length; i++)
{
if(CKS[i] != CMS[i])
throw new Exception("KeyWrap CheckSum failed");
}
//8. WK is the wrapped key, now extracted for use in data decryption.
return WK;
}
