/********EXTERNAL OBJECT PUBLIC METHODS - END ********/
/// <summary>
/// Gets the BufferedBlockCipher loaded with Padding, Mode and Engine to Encrypt with a Symmetric Block Algorithm
/// </summary>
/// <param name="algorithm">string SymmetricBlockAlgorithm enum, symmetric block algorithm name</param>
/// <param name="mode">string SymmetricBlockModes enum, symmetric block mode name</param>
/// <param name="padding">string SymmetricBlockPadding enum, symmetric block padding name</param>
/// <returns>BufferedBlockCipher loaded with Padding, Mode and Engine to Encrypt with a Symmetric Block Algorithm</returns>
private BufferedBlockCipher getCipher(SymmetricBlockAlgorithm algorithm, SymmetricBlockMode mode,
SymmetricBlockPadding padding)
{
IBlockCipher engine = getCipherEngine(algorithm);
IBlockCipherPadding paddingCipher = getPadding(padding);
IBlockCipher bc;
if (mode != SymmetricBlockMode.ECB)
{
bc = getCipherMode(engine, mode);
}
else
{
bc = engine;
}
// si el padding es WITHCTS el paddingCipher es null
if (usesCTS(mode, padding))
{
return(new CtsBlockCipher(bc)); // no usa el paddingCipher que es el null
}
if (padding == SymmetricBlockPadding.NOPADDING)
{
return(new BufferedBlockCipher(bc));
}
else
{
return(new PaddedBufferedBlockCipher(bc, paddingCipher));
}
}
/// <summary>
/// Mapping between SymmetricBlockPadding enum representation and string name
/// </summary>
/// <param name="symmetricBlockPadding">SymmetricBlockPadding enum, padding name</param>
/// <param name="error">Error type for error management</param>
/// <returns>string name value of SymmetricBlockPadding</returns>
public static string valueOf(SymmetricBlockPadding symmetricBlockPadding, Error error)
{
switch (symmetricBlockPadding)
{
case SymmetricBlockPadding.NOPADDING:
return("NOPADDING");
case SymmetricBlockPadding.PKCS7PADDING:
return("PKCS7PADDING");
case SymmetricBlockPadding.ISO10126D2PADDING:
return("ISO10126D2PADDING");
case SymmetricBlockPadding.X923PADDING:
return("X923PADDING");
case SymmetricBlockPadding.ISO7816D4PADDING:
return("ISO7816D4PADDING");
case SymmetricBlockPadding.ZEROBYTEPADDING:
return("ZEROBYTEPADDING");
case SymmetricBlockPadding.WITHCTS:
return("WITHCTS");
default:
error.setError("SB009", "Unrecognized SymmetricBlockPadding");
return("Unrecognized block padding");
}
}
/// <summary>
/// Builds an IBlockCipherPadding
/// </summary>
/// <param name="padding">SymmetricBlockPadding enum, padding name</param>
/// <returns>IBlockCipherPadding with loaded padding type, if padding is WITHCTS returns null</returns>
private IBlockCipherPadding getPadding(SymmetricBlockPadding padding)
{
IBlockCipherPadding paddingCipher = null;
switch (padding)
{
case SymmetricBlockPadding.NOPADDING:
paddingCipher = null;
break;
case SymmetricBlockPadding.ISO7816D4PADDING:
paddingCipher = new ISO7816d4Padding();
break;
case SymmetricBlockPadding.ISO10126D2PADDING:
paddingCipher = new ISO10126d2Padding();
break;
case SymmetricBlockPadding.PKCS7PADDING:
paddingCipher = new Pkcs7Padding();
break;
case SymmetricBlockPadding.WITHCTS:
break;
case SymmetricBlockPadding.X923PADDING:
paddingCipher = new X923Padding();
break;
case SymmetricBlockPadding.ZEROBYTEPADDING:
paddingCipher = new ZeroBytePadding();
break;
default:
this.error.setError("SB018", "Cipher " + padding + " not recognised.");
break;
}
return(paddingCipher);
}
/// <summary>
/// True if it uses CTS
/// </summary>
/// <param name="mode">string SymmetricBlockModes enum, symmetric block mode name</param>
/// <param name="padding">string SymmetricBlockPadding enum, symmetric block padding name</param>
/// <returns>boolean true if it uses CTS</returns>
private bool usesCTS(SymmetricBlockMode mode, SymmetricBlockPadding padding)
{
return(mode == SymmetricBlockMode.CTS || padding == SymmetricBlockPadding.WITHCTS);
}
public string DoDecrypt(string symmetricBlockAlgorithm, string symmetricBlockMode,
string symmetricBlockPadding, string key, string IV, string encryptedInput)
{
this.error.cleanError();
SymmetricBlockAlgorithm algorithm = SymmetricBlockAlgorithmUtils.getSymmetricBlockAlgorithm(symmetricBlockAlgorithm, this.error);
SymmetricBlockMode mode = SymmetricBlockModeUtils.getSymmetricBlockMode(symmetricBlockMode, this.error);
SymmetricBlockPadding padding = SymmetricBlockPaddingUtils.getSymmetricBlockPadding(symmetricBlockPadding, this.error);
if (this.error.existsError())
{
return("");
}
BufferedBlockCipher bbc = getCipher(algorithm, mode, padding);
if (this.error.existsError() && !(string.Compare(this.error.Code, "SB016", true) == 0))
{
return("");
}
byte[] bytesKey = SecurityUtils.GetHexa(key, "SB023", this.error);
byte[] bytesIV = SecurityUtils.GetHexa(IV, "SB023", this.error);
if (this.HasError())
{
return("");
}
KeyParameter keyParam = new KeyParameter(bytesKey);
if (SymmetricBlockMode.ECB != mode && SymmetricBlockMode.OPENPGPCFB != mode)
{
ParametersWithIV keyParamWithIV = new ParametersWithIV(keyParam, bytesIV);
try
{
bbc.Init(false, keyParamWithIV);
}catch (Exception e)
{
this.error.setError("SB027", e.Message);
return("");
}
}
else
{
try
{
bbc.Init(false, keyParam);
}catch (Exception e)
{
this.error.setError("SB028", e.Message);
return("");
}
}
byte[] out2 = Base64.Decode(encryptedInput);
byte[] comparisonBytes = new byte[bbc.GetOutputSize(out2.Length)];
int length = bbc.ProcessBytes(out2, 0, out2.Length, comparisonBytes, 0);
try
{
bbc.DoFinal(comparisonBytes, length);
}
catch (Exception)
{
this.error.setError("SB015", "Block decryption exception");
return("");
}
this.error.cleanError();
EncodingUtil eu = new EncodingUtil();
this.error = eu.GetError();
return(eu.getString(comparisonBytes));
}
public string DoEncrypt(string symmetricBlockAlgorithm, string symmetricBlockMode,
string symmetricBlockPadding, string key, string IV, string plainText)
{
this.error.cleanError();
SymmetricBlockAlgorithm algorithm = SymmetricBlockAlgorithmUtils.getSymmetricBlockAlgorithm(symmetricBlockAlgorithm, this.error);
SymmetricBlockMode mode = SymmetricBlockModeUtils.getSymmetricBlockMode(symmetricBlockMode, this.error);
SymmetricBlockPadding padding = SymmetricBlockPaddingUtils.getSymmetricBlockPadding(symmetricBlockPadding, this.error);
if (this.error.existsError())
{
return("");
}
BufferedBlockCipher bbc = getCipher(algorithm, mode, padding);
if (this.error.existsError() && !(string.Compare(this.error.Code, "SB016", true) == 0))
{
return("");
}
byte[] byteIV = SecurityUtils.GetHexa(IV, "SB022", this.error);
byte[] byteKey = SecurityUtils.GetHexa(key, "SB022", this.error);
if (this.HasError())
{
return("");
}
KeyParameter keyParam = new KeyParameter(byteKey);
if (SymmetricBlockMode.ECB != mode && SymmetricBlockMode.OPENPGPCFB != mode)
{
ParametersWithIV keyParamWithIV = new ParametersWithIV(keyParam, byteIV);
try{
bbc.Init(true, keyParamWithIV);
}catch (Exception e)
{
this.error.setError("SB025", e.Message);
return("");
}
}
else
{
try
{
bbc.Init(true, keyParam);
}catch (Exception e)
{
this.error.setError("SB026", e.Message);
return("");
}
}
EncodingUtil eu = new EncodingUtil();
byte[] inputBytes = eu.getBytes(plainText);
if (eu.GetError().existsError())
{
this.error = eu.GetError();
return("");
}
byte[] outputBytes = new byte[bbc.GetOutputSize(inputBytes.Length)];
int length = bbc.ProcessBytes(inputBytes, 0, inputBytes.Length, outputBytes, 0);
try
{
bbc.DoFinal(outputBytes, length);
}
catch (Exception)
{
this.error.setError("SB013", "Block encryption exception");
return("");
}
string result = Base64.ToBase64String(outputBytes);
if (result == null || result.Length == 0)
{
this.error.setError("SB014", "Error encoding base64");
return("");
}
this.error.cleanError();
return(result);
}
