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);
}
/// <summary>
/// Resigns save data.
/// </summary>
/// <param name="sav7">The save data to resign.</param>
/// <param name="throwIfUnsupported">If true, throw an <see cref="InvalidOperationException"/> if MemeCrypto is unsupported. If false, calling this function will have no effect.</param>
/// <exception cref="InvalidOperationException">Thrown if the current platform has FIPS mode enabled on a platform that does not support the required crypto service providers.</exception>
/// <returns>The resigned save data.</returns>
public static byte[] Resign(byte[] sav7, bool throwIfUnsupported = true)
{
if (sav7 == null || sav7.Length != 0x6BE00)
{
return(null);
}
try
{
byte[] outSav = (byte[])sav7.Clone();
using (var sha1 = Util.GetSHA1Provider())
{
using (var sha256 = Util.GetSHA256Provider())
{
byte[] CurSig = new byte[0x80];
Array.Copy(sav7, 0x6BB00, CurSig, 0, 0x80);
byte[] ChecksumTable = new byte[0x140];
Array.Copy(sav7, 0x6BC00, ChecksumTable, 0, 0x140);
byte[] Hash = sha256.ComputeHash(ChecksumTable);
byte[] PubKeyDer = "307C300D06092A864886F70D0101010500036B003068026100B61E192091F90A8F76A6EAAA9A3CE58C863F39AE253F037816F5975854E07A9A456601E7C94C29759FE155C064EDDFA111443F81EF1A428CF6CD32F9DAC9D48E94CFB3F690120E8E6B9111ADDAF11E7C96208C37C0143FF2BF3D7E831141A9730203010001".ToByteArray();
byte[] keybuf = new byte[PubKeyDer.Length + 0x20];
Array.Copy(PubKeyDer, keybuf, PubKeyDer.Length);
Array.Copy(Hash, 0, keybuf, PubKeyDer.Length, 0x20);
byte[] key = sha1.ComputeHash(keybuf).Take(0x10).ToArray();
byte[] secret = ReverseCrypt(CurSig) ?? new byte[0x60];
byte[] secretWorkBuf = new byte[0x78];
Hash.CopyTo(secretWorkBuf, 0);
Array.Copy(secret, 0, secretWorkBuf, 0x20, 0x58);
Array.Copy(sha1.ComputeHash(secretWorkBuf), 0, secret, 0x58, 8);
Hash.CopyTo(outSav, 0x6BB00);
byte[] MemeCrypted = MemeCryptoAESEncrypt(key, secret);
MemeCrypted[0] &= 0x7F;
var RSA = RSADecrypt(MemeCrypted);
Array.Copy(RSA, 0, outSav, 0x6BB20, 0x60);
}
}
return(outSav);
}
catch (InvalidOperationException)
{
if (throwIfUnsupported)
{
throw;
}
else
{
return((byte[])sav7.Clone());
}
}
}
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);
}
}
