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using System;
using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.Crypto.Generators;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Security;
using Org.BouncyCastle.Utilities;
namespace Org.BouncyCastle.OpenSsl
{
internal sealed class PemUtilities
{
private enum PemBaseAlg { AES_128, AES_192, AES_256, BF, DES, DES_EDE, DES_EDE3, RC2, RC2_40, RC2_64 };
private enum PemMode { CBC, CFB, ECB, OFB };
static PemUtilities()
{
// Signal to obfuscation tools not to change enum constants
Enums.GetArbitraryValue<PemBaseAlg>().ToString();
Enums.GetArbitraryValue<PemMode>().ToString();
}
private static void ParseDekAlgName(
string dekAlgName,
out PemBaseAlg baseAlg,
out PemMode mode)
{
try
{
mode = PemMode.ECB;
if (dekAlgName == "DES-EDE" || dekAlgName == "DES-EDE3")
{
baseAlg = Enums.GetEnumValue<PemBaseAlg>(dekAlgName);
return;
}
int pos = dekAlgName.LastIndexOf('-');
if (pos >= 0)
{
baseAlg = Enums.GetEnumValue<PemBaseAlg>(dekAlgName.Substring(0, pos));
mode = Enums.GetEnumValue<PemMode>(dekAlgName.Substring(pos + 1));
return;
}
}
catch (ArgumentException)
{
}
throw new EncryptionException("Unknown DEK algorithm: " + dekAlgName);
}
internal static byte[] Crypt(
bool encrypt,
byte[] bytes,
char[] password,
string dekAlgName,
byte[] iv)
{
PemBaseAlg baseAlg;
PemMode mode;
ParseDekAlgName(dekAlgName, out baseAlg, out mode);
string padding;
switch (mode)
{
case PemMode.CBC:
case PemMode.ECB:
padding = "PKCS5Padding";
break;
case PemMode.CFB:
case PemMode.OFB:
padding = "NoPadding";
break;
default:
throw new EncryptionException("Unknown DEK algorithm: " + dekAlgName);
}
string algorithm;
byte[] salt = iv;
switch (baseAlg)
{
case PemBaseAlg.AES_128:
case PemBaseAlg.AES_192:
case PemBaseAlg.AES_256:
algorithm = "AES";
if (salt.Length > 8)
{
salt = new byte[8];
Array.Copy(iv, 0, salt, 0, salt.Length);
}
break;
case PemBaseAlg.BF:
algorithm = "BLOWFISH";
break;
case PemBaseAlg.DES:
algorithm = "DES";
break;
case PemBaseAlg.DES_EDE:
case PemBaseAlg.DES_EDE3:
algorithm = "DESede";
break;
case PemBaseAlg.RC2:
case PemBaseAlg.RC2_40:
case PemBaseAlg.RC2_64:
algorithm = "RC2";
break;
default:
throw new EncryptionException("Unknown DEK algorithm: " + dekAlgName);
}
string cipherName = algorithm + "/" + mode + "/" + padding;
IBufferedCipher cipher = CipherUtilities.GetCipher(cipherName);
ICipherParameters cParams = GetCipherParameters(password, baseAlg, salt);
if (mode != PemMode.ECB)
{
cParams = new ParametersWithIV(cParams, iv);
}
cipher.Init(encrypt, cParams);
return cipher.DoFinal(bytes);
}
private static ICipherParameters GetCipherParameters(
char[] password,
PemBaseAlg baseAlg,
byte[] salt)
{
string algorithm;
int keyBits;
switch (baseAlg)
{
case PemBaseAlg.AES_128: keyBits = 128; algorithm = "AES128"; break;
case PemBaseAlg.AES_192: keyBits = 192; algorithm = "AES192"; break;
case PemBaseAlg.AES_256: keyBits = 256; algorithm = "AES256"; break;
case PemBaseAlg.BF: keyBits = 128; algorithm = "BLOWFISH"; break;
case PemBaseAlg.DES: keyBits = 64; algorithm = "DES"; break;
case PemBaseAlg.DES_EDE: keyBits = 128; algorithm = "DESEDE"; break;
case PemBaseAlg.DES_EDE3: keyBits = 192; algorithm = "DESEDE3"; break;
case PemBaseAlg.RC2: keyBits = 128; algorithm = "RC2"; break;
case PemBaseAlg.RC2_40: keyBits = 40; algorithm = "RC2"; break;
case PemBaseAlg.RC2_64: keyBits = 64; algorithm = "RC2"; break;
default:
return null;
}
OpenSslPbeParametersGenerator pGen = new OpenSslPbeParametersGenerator();
pGen.Init(PbeParametersGenerator.Pkcs5PasswordToBytes(password), salt);
return pGen.GenerateDerivedParameters(algorithm, keyBits);
}
}
}
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