public static byte[] Encrypt_v15(RSA rsa, RandomNumberGenerator rng, byte[] M)
{
int size = rsa.KeySize / 8;
if (M.Length > size - 11)
{
throw new CryptographicException("message too long");
}
int count = System.Math.Max(8, size - M.Length - 3);
byte[] data = new byte[count];
rng.GetNonZeroBytes(data);
byte[] x = new byte[size];
x[1] = (byte)2;
Buffer.BlockCopy((Array)data, 0, (Array)x, 2, count);
Buffer.BlockCopy((Array)M, 0, (Array)x, size - M.Length, M.Length);
byte[] m = PKCS1.OS2IP(x);
return(PKCS1.I2OSP(PKCS1.RSAEP(rsa, m), size));
}
public static bool Verify_v15(
RSA rsa,
HashAlgorithm hash,
byte[] hashValue,
byte[] signature,
bool tryNonStandardEncoding)
{
int num = rsa.KeySize >> 3;
byte[] s = PKCS1.OS2IP(signature);
byte[] array2 = PKCS1.I2OSP(PKCS1.RSAVP1(rsa, s), num);
bool flag = PKCS1.Compare(PKCS1.Encode_v15(hash, hashValue, num), array2);
if (flag || !tryNonStandardEncoding)
{
return(flag);
}
if (array2[0] != (byte)0 || array2[1] != (byte)1)
{
return(false);
}
int index1;
for (index1 = 2; index1 < array2.Length - hashValue.Length - 1; ++index1)
{
if (array2[index1] != byte.MaxValue)
{
return(false);
}
}
byte[] numArray = array2;
int index2 = index1;
int srcOffset = index2 + 1;
if (numArray[index2] != (byte)0)
{
return(false);
}
byte[] array1 = new byte[hashValue.Length];
Buffer.BlockCopy((Array)array2, srcOffset, (Array)array1, 0, array1.Length);
return(PKCS1.Compare(array1, hashValue));
}
public static byte[] Encrypt_v15(RSA rsa, RandomNumberGenerator rng, byte[] M)
{
int num = rsa.KeySize / 8;
if (M.Length > num - 11)
{
throw new CryptographicException("message too long");
}
int num2 = Math.Max(8, num - M.Length - 3);
byte[] array = new byte[num2];
rng.GetNonZeroBytes(array);
byte[] array2 = new byte[num];
array2[1] = 2;
Buffer.BlockCopy(array, 0, array2, 2, num2);
Buffer.BlockCopy(M, 0, array2, num - M.Length, M.Length);
byte[] m = PKCS1.OS2IP(array2);
byte[] x = PKCS1.RSAEP(rsa, m);
return(PKCS1.I2OSP(x, num));
}
public override byte[] CreateSignature(byte[] rgbHash)
{
if (this.key == null)
{
throw new CryptographicUnexpectedOperationException("The key is a null reference");
}
if (hash == null)
{
throw new CryptographicUnexpectedOperationException("The hash algorithm is a null reference.");
}
if (rgbHash == null)
{
throw new ArgumentNullException("The rgbHash parameter is a null reference.");
}
#pragma warning disable 436
return(PKCS1.Sign_v15(key, hash.Algorithm, rgbHash));
#pragma warning restore 436
}
public static byte[] Decrypt_OAEP(RSA rsa, HashAlgorithm hash, byte[] C)
{
int num = rsa.KeySize / 8;
int num2 = hash.HashSize / 8;
if (num < 2 * num2 + 2 || C.Length != num)
{
throw new CryptographicException("decryption error");
}
byte[] c = PKCS1.OS2IP(C);
byte[] x = PKCS1.RSADP(rsa, c);
byte[] array = PKCS1.I2OSP(x, num);
byte[] array2 = new byte[num2];
Buffer.BlockCopy(array, 1, array2, 0, array2.Length);
byte[] array3 = new byte[num - num2 - 1];
Buffer.BlockCopy(array, array.Length - array3.Length, array3, 0, array3.Length);
byte[] array4 = PKCS1.MGF1(hash, array3, num2);
byte[] mgfSeed = PKCS1.xor(array2, array4);
byte[] array5 = PKCS1.MGF1(hash, mgfSeed, num - num2 - 1);
byte[] array6 = PKCS1.xor(array3, array5);
byte[] emptyHash = PKCS1.GetEmptyHash(hash);
byte[] array7 = new byte[emptyHash.Length];
Buffer.BlockCopy(array6, 0, array7, 0, array7.Length);
bool flag = PKCS1.Compare(emptyHash, array7);
int num3 = emptyHash.Length;
while (array6[num3] == 0)
{
num3++;
}
int num4 = array6.Length - num3 - 1;
byte[] array8 = new byte[num4];
Buffer.BlockCopy(array6, num3 + 1, array8, 0, num4);
if (array[0] != 0 || !flag || array6[num3] != 1)
{
return(null);
}
return(array8);
}
public static bool Verify_v15(RSA rsa, HashAlgorithm hash, byte[] hashValue, byte[] signature)
{
return(PKCS1.Verify_v15(rsa, hash, hashValue, signature, false));
}
public static byte[] I2OSP(int x, int size)
{
byte[] bytes = BitConverterLE.GetBytes(x);
Array.Reverse((Array)bytes, 0, bytes.Length);
return(PKCS1.I2OSP(bytes, size));
}
