public byte[] RSAES_OAEP_DECRYPT(Models.RSAPrivateKey K, byte[] C, string L)
{
BigInteger n = K.p * K.q;
int mLen = (int)Math.Pow(2, 65) - 1;
int hLen = 256 / 8;
int k = n.ToByteArray().Length;
if (L.Length > mLen)
{
throw new Exception("decryption error");
}
if (C.Length != k)
{
throw new Exception("decryption error");
}
if (k < 2 * hLen + 2)
{
throw new Exception("decryption error");
}
BigInteger c = OS2IP(C);
BigInteger m = RSADP(K, c);
byte[] EM = I2OSP(m, k);
// EME-OAEP decoding
SHA256Managed hashString = new SHA256Managed();
byte[] lHash = hashString.ComputeHash(Encoding.ASCII.GetBytes(L));
byte[] Y = new byte[] { EM[0] };
byte[] maskedSeed = new byte[hLen];
byte[] maskedDB = new byte[k - hLen - 1];
Buffer.BlockCopy(EM, 1, maskedSeed, 0, hLen);
Buffer.BlockCopy(EM, hLen + 1, maskedDB, 0, k - hLen - 1);
byte[] seedMask = MGF1(maskedDB, hLen);
byte[] seed = new byte[hLen];
for (int i = 0; i < hLen; i++)
{
seed[i] = (byte)(maskedSeed[i] ^ seedMask[i]);
}
byte[] dbMask = MGF1(seed, k - hLen - 1);
byte[] DB = new byte[k - hLen - 1];
for (int i = 0; i < k - hLen - 1; i++)
{
DB[i] = (byte)(maskedDB[i] ^ dbMask[i]);
}
//.......................................Page 26
throw new NotImplementedException();
}
public BigInteger RSASP1(Models.RSAPrivateKey K, BigInteger m)
{
if (m <= 0 || m >= (K.p * K.q - 1))
{
throw new Exception("message representative out of range");
}
BigInteger s_1 = BigInteger.ModPow(m, K.dP, K.p);
BigInteger s_2 = BigInteger.ModPow(m, K.dQ, K.q);
BigInteger h = (s_1 - s_2) * K.qInv % K.p;
BigInteger s = s_2 + K.q * h;
return(s);
}
public BigInteger RSADP(Models.RSAPrivateKey K, BigInteger c)
{
if (c <= 0 || c >= (K.p * K.q - 1))
{
throw new Exception("ciphertext representative out of range");
}
BigInteger m_1 = BigInteger.ModPow(c, K.dP, K.p);
BigInteger m_2 = BigInteger.ModPow(c, K.dQ, K.q);
BigInteger h = (m_1 - m_2) * K.qInv % K.p;
BigInteger m = m_2 + K.q * h;
return(m);
}
public byte[] RSASSA_PKCS1_V1_5_SIGN(Models.RSAPrivateKey K, byte[] M)
{
throw new NotImplementedException();
}
public byte[] RSAES_PKCS1_V1_5_DECRYPT(Models.RSAPrivateKey K, byte[] M)
{
throw new NotImplementedException();
}
