private static byte[] ReverseCrypt(byte[] input)
{
if (input.Length != 0x80)
{
throw new ArgumentException("Invalid Memecrypto decryption byte[]!");
}
using (var sha1 = Util.GetSHA1Provider())
{
byte[] PubKeyDer = "307C300D06092A864886F70D0101010500036B003068026100B61E192091F90A8F76A6EAAA9A3CE58C863F39AE253F037816F5975854E07A9A456601E7C94C29759FE155C064EDDFA111443F81EF1A428CF6CD32F9DAC9D48E94CFB3F690120E8E6B9111ADDAF11E7C96208C37C0143FF2BF3D7E831141A9730203010001".ToByteArray();
byte[] enc = new byte[0x60];
Array.Copy(input, 0x20, enc, 0, 0x60);
byte[] keybuf = new byte[PubKeyDer.Length + 0x20];
Array.Copy(PubKeyDer, keybuf, PubKeyDer.Length);
Array.Copy(input, 0, keybuf, PubKeyDer.Length, 0x20);
byte[] key = sha1.ComputeHash(keybuf).Take(0x10).ToArray();
byte[] RSA = RSAEncrypt(enc);
var dec = MemeCryptoAESDecrypt(key, RSA);
if (sha1.ComputeHash(dec).Take(0x8).SequenceEqual(dec.Skip(0x58)))
{
return(dec);
}
RSA[0] |= 0x80;
dec = MemeCryptoAESDecrypt(key, RSA);
if (sha1.ComputeHash(dec).Take(0x8).SequenceEqual(dec.Skip(0x58)))
{
return(dec);
}
}
return(null);
}
private static byte[] ReverseCrypt(byte[] input, int meme_ofs, int memeindex)
{
var output = (byte[])input.Clone();
var memekey = MemeKeys[memeindex];
using (var sha1 = Util.GetSHA1Provider())
{
var enc = new byte[0x60];
Array.Copy(input, meme_ofs, enc, 0, 0x60);
var keybuf = new byte[memekey.DER.Length + meme_ofs];
Array.Copy(memekey.DER, keybuf, memekey.DER.Length);
if (meme_ofs > 0)
{
Array.Copy(input, 0, keybuf, memekey.DER.Length, meme_ofs);
}
var key = sha1.ComputeHash(keybuf).Take(0x10).ToArray();
var RSA = RSAEncrypt(enc, memeindex);
MemeCryptoAESDecrypt(key, RSA).CopyTo(output, meme_ofs);
if (sha1.ComputeHash(output, 0, meme_ofs + 0x58).Take(0x8).SequenceEqual(output.Skip(meme_ofs + 0x58).Take(0x8)))
{
return(output);
}
RSA[0] |= 0x80;
MemeCryptoAESDecrypt(key, RSA).CopyTo(output, meme_ofs);
if (sha1.ComputeHash(output, 0, meme_ofs + 0x58).Take(0x8).SequenceEqual(output.Skip(meme_ofs + 0x58).Take(0x8)))
{
return(output);
}
}
return(null);
}
public static byte[] SignMemeData(byte[] input)
{
if (input.Length < 0x60)
{
throw new ArgumentException("Bad Meme input!");
}
byte[] PubKeyDer = "307C300D06092A864886F70D0101010500036B003068026100B61E192091F90A8F76A6EAAA9A3CE58C863F39AE253F037816F5975854E07A9A456601E7C94C29759FE155C064EDDFA111443F81EF1A428CF6CD32F9DAC9D48E94CFB3F690120E8E6B9111ADDAF11E7C96208C37C0143FF2BF3D7E831141A9730203010001".ToByteArray();
using (var sha1 = Util.GetSHA1Provider())
{
byte[] key = sha1.ComputeHash(PubKeyDer.Concat(input.Take(input.Length - 0x60)).ToArray()).Take(0x10).ToArray();
byte[] output = (byte[])input.Clone();
Array.Copy(sha1.ComputeHash(input, 0, input.Length - 8), 0, output, output.Length - 8, 8);
byte[] MemeCrypted = MemeCryptoAESEncrypt(key, output.Skip(output.Length - 0x60).ToArray());
MemeCrypted[0] &= 0x7F;
var RSA = RSADecrypt(MemeCrypted);
RSA.CopyTo(output, output.Length - 0x60);
return(output);
}
}
public static byte[] SignMemeData(byte[] input)
{
if (input.Length < 0x60)
{
throw new ArgumentException("Bad Meme input!");
}
const int memeindex = 3;
using (var sha1 = Util.GetSHA1Provider())
{
var key = sha1.ComputeHash(MemeKeys[memeindex].DER.Concat(input.Take(input.Length - 0x60)).ToArray()).Take(0x10).ToArray();
var output = (byte[])input.Clone();
Array.Copy(sha1.ComputeHash(input, 0, input.Length - 8), 0, output, output.Length - 8, 8);
var MemeCrypted = MemeCryptoAESEncrypt(key, output.Skip(output.Length - 0x60).ToArray());
MemeCrypted[0] &= 0x7F;
var RSA = RSADecrypt(MemeCrypted);
RSA.CopyTo(output, output.Length - 0x60);
return(output);
}
}