public void Encrypt(BufRef dest, BufLen data, bool zeropad)
{
if (data == null || data.Length > 222)
{
throw new InvalidParameterException("ElGamal data length can max be 222 bytes!");
}
var hashbuf = new BufRefLen(new byte[255]);
hashbuf.Write8(0xFF);
hashbuf.Write(I2PHashSHA256.GetHash(data));
hashbuf.Write(data);
hashbuf.Reset();
var b = b1.Multiply(new BigInteger(1, hashbuf.ToByteArray())).Mod(I2PConstants.ElGamalP);
if (zeropad)
{
dest.Write8(0);
dest.Write(a.ToByteArray(256));
dest.Write8(0);
dest.Write(b.ToByteArray(256));
}
else
{
dest.Write(a.ToByteArray(256));
dest.Write(b.ToByteArray(256));
}
}
public static bool Equal(BufRefLen b1, BufRefLen b2)
{
if (Object.ReferenceEquals(b1, null) && Object.ReferenceEquals(b2, null))
{
return(true);
}
if (Object.ReferenceEquals(b1, null) || Object.ReferenceEquals(b2, null))
{
return(false);
}
if (Object.ReferenceEquals(b1, b2))
{
return(true);
}
if (b1.Length != b2.Length)
{
return(false);
}
for (int i = 0; i < b1.Length; ++i)
{
if (b1.BaseArray[b1.BaseArrayOffset + i] != b2.BaseArray[b2.BaseArrayOffset + i])
{
return(false);
}
}
return(true);
}
public static void Encrypt(BufRef dest, BufLen data, I2PPublicKey key, bool zeropad)
{
if (data == null || data.Length > ClearTextLength)
{
throw new InvalidParameterException($"ElGamal data must be {ClearTextLength} bytes or less!");
}
var k = new BigInteger(I2PConstants.ElGamalFullExponentBits, Rnd);
var a = I2PConstants.ElGamalG.ModPow(k, I2PConstants.ElGamalP);
var b1 = key.ToBigInteger().ModPow(k, I2PConstants.ElGamalP);
var start = new BufLen(new byte[EGBlockLength]);
var writer = new BufRefLen(start, 1);
start[0] = 0xFF;
writer.Write(I2PHashSHA256.GetHash(data));
writer.Write(data);
var egblock = new BufLen(start, 0, writer - start);
var egint = egblock.ToBigInteger();
var b = b1.Multiply(egint).Mod(I2PConstants.ElGamalP);
var targetlen = zeropad
? EncryptedPaddedLength / 2
: EncryptedShortLength / 2;
WriteToDest(dest, a, targetlen);
WriteToDest(dest, b, targetlen);
}
bool IEquatable <BufRefLen> .Equals(BufRefLen other)
{
if (Object.ReferenceEquals(other, null))
{
return(false);
}
return(Equal(this, other));
}
public void Poke(BufRefLen src, int offset, int maxlen)
{
var len = Math.Min(maxlen, src.Length);
PreWriteCheck(offset + len);
Array.Copy(src.Data, src.Position, Data, Position + offset, len);
}
bool IEquatable <BufRefLen> .Equals(BufRefLen other)
{
if (other is null)
{
return(false);
}
return(Equal(this, other));
}
public virtual int Write(BufRefLen src)
{
PreWriteCheck(src.Length);
Array.Copy(src.BaseArray, src.BaseArrayOffset, BaseArray, BaseArrayOffset, src.Length);
Seek(src.Length);
src.Seek(src.Length);
return(src.Length);
}
public BufRefLen ReadBufRefLen(int length)
{
PreReadCheck(length);
var result = new BufRefLen(this, 0, length);
Seek(length);
return(result);
}
public static string Encode(BufLen data)
{
var result = new StringBuilder();
var reader = new BufRefLen(data);
byte v1, v2;
for (int i = 0; i < data.Length / 3; ++i)
{
v1 = reader.Read8();
v2 = (byte)((v1 << 4) & 0x30);
v1 >>= 2;
result.Append(Domain[v1]);
v1 = reader.Read8();
v2 |= (byte)(v1 >> 4);
result.Append(Domain[v2]);
v1 = (byte)((v1 & 0x0f) << 2);
v2 = reader.Read8();
v1 |= (byte)(v2 >> 6);
result.Append(Domain[v1]);
v2 &= 0x3f;
result.Append(Domain[v2]);
}
switch (data.Length % 3)
{
case 1:
v1 = reader.Read8();
v2 = (byte)((v1 << 4) & 0x3f);
v1 >>= 2;
result.Append(Domain[v1]);
result.Append(Domain[v2]);
result.Append("==");
break;
case 2:
v1 = reader.Read8();
v2 = (byte)((v1 << 4) & 0x3f);
v1 >>= 2;
result.Append(Domain[v1]);
v1 = reader.Read8();
v2 |= (byte)(v1 >> 4);
result.Append(Domain[v2]);
v1 = (byte)((v1 & 0x0f) << 2);
result.Append(Domain[v1]);
result.Append("=");
break;
}
return(result.ToString());
}
public static BufLen Generate(IEnumerable <BufLen> msg, BufLen key, BufLen dest)
{
if (key.Length != 32)
{
throw new NotImplementedException("Only keys of 32 bits supported");
}
var m5 = new MD5Digest();
var hash = new byte[m5.GetDigestSize()];
var buf = new byte[BLOCK_LENGTH];
var writer = new BufRefLen(buf);
writer.Write64(key.Peek64(0) ^ IPAD);
writer.Write64(key.Peek64(1 * 8) ^ IPAD);
writer.Write64(key.Peek64(2 * 8) ^ IPAD);
writer.Write64(key.Peek64(3 * 8) ^ IPAD);
m5.BlockUpdate(buf, 0, BLOCK_LENGTH);
m5.BlockUpdate(IPADBUF, 0, IPADBUF.Length);
foreach (var one in msg)
{
m5.BlockUpdate(one.BaseArray, one.BaseArrayOffset, one.Length);
}
m5.DoFinal(hash, 0);
writer = new BufRefLen(buf);
writer.Write64(key.Peek64(0) ^ OPAD);
writer.Write64(key.Peek64(1 * 8) ^ OPAD);
writer.Write64(key.Peek64(2 * 8) ^ OPAD);
writer.Write64(key.Peek64(3 * 8) ^ OPAD);
m5.Reset();
m5.BlockUpdate(buf, 0, BLOCK_LENGTH);
m5.BlockUpdate(OPADBUF, 0, OPADBUF.Length);
m5.BlockUpdate(hash, 0, hash.Length);
m5.BlockUpdate(NULLPAD, 0, NULLPAD.Length);
if (dest.Length < m5.GetDigestSize())
{
throw new OverflowException("Not enough dest buffer size for I2PHMACMD5Digest.Generate()!");
}
m5.DoFinal(dest.BaseArray, dest.BaseArrayOffset);
return(dest);
}
public static byte[] BCGZipDecompress(BufLen buf)
{
var reader = new BufRefLen(buf);
using (var ms = new MemoryStream())
{
// Skip gzip header
var gzheader = reader.ReadBufLen(10);
var flag = gzheader.Peek8(3);
if ((flag & 0x04) != 0)
{
reader.Seek(reader.Read16()); // "Extra"
}
if ((flag & 0x08) != 0)
{
while (reader.Read8() != 0)
{
; // "Name"
}
}
if ((flag & 0x10) != 0)
{
while (reader.Read8() != 0)
{
; // "Comment"
}
}
if ((flag & 0x02) != 0)
{
reader.Read16(); // "CRC16"
}
ms.Write(reader.BaseArray, reader.BaseArrayOffset, reader.Length);
ms.Position = 0;
using (var gzs = new ZInputStream(ms, true))
{
var gzdata = StreamUtils.Read(gzs);
return(gzdata);
}
}
}
public static BufLen Decrypt(BufLen data, I2PPrivateKey pkey, bool zeropad)
{
if (data == null || (zeropad && data.Length != 514))
{
throw new ArgumentException("ElGamal padded data to decrypt must be exactly 514 bytes!");
}
if (!zeropad && data.Length != 512)
{
throw new ArgumentException("ElGamal data to decrypt must be exactly 512 bytes!");
}
var x = I2PConstants.ElGamalP.Subtract(pkey.ToBigInteger()).Subtract(BigInteger.One);
BigInteger a, b;
var reader = new BufRefLen(data);
if (zeropad)
{
reader.Seek(1);
a = reader.ReadBigInteger(256);
reader.Seek(1);
b = reader.ReadBigInteger(256);
}
else
{
a = reader.ReadBigInteger(256);
b = reader.ReadBigInteger(256);
}
var m2 = b.Multiply(a.ModPow(x, I2PConstants.ElGamalP));
var m1 = m2.Mod(I2PConstants.ElGamalP);
var m = m1.ToByteArray(255);
var hash = I2PHashSHA256.GetHash(m, 33, 222);
if (!BufUtils.Equal(m, 1, hash, 0, 32))
{
throw new HashCheckFailException();
}
return(new BufLen(m, 33, 222));
}
public static int ComputeHash(BufRefLen data)
{
unchecked
{
const int p = 16777619;
int hash = (int)2166136261;
var end = data.BaseArrayOffset + data.Length;
for (int i = data.BaseArrayOffset; i < end; ++i)
{
hash = (hash ^ data.BaseArray[i]) * p;
}
hash += hash << 13;
hash ^= hash >> 7;
hash += hash << 3;
hash ^= hash >> 17;
hash += hash << 5;
return(hash);
}
}
public static int Compare(BufRefLen b1, BufRefLen b2)
{
if (Object.ReferenceEquals(b1, null) && Object.ReferenceEquals(b2, null))
{
return(0);
}
if (Object.ReferenceEquals(b1, null))
{
return(-1);
}
if (Object.ReferenceEquals(b2, null))
{
return(1);
}
if (Object.ReferenceEquals(b1, b2))
{
return(0);
}
for (int i = 0; i < b1.Length; ++i)
{
if (i >= b2.Length)
{
return(1);
}
var c = b1.BaseArray[b1.BaseArrayOffset + i] - b2.BaseArray[b2.BaseArrayOffset + i];
if (c != 0)
{
return(Math.Sign(c));
}
}
if (b2.Length > b1.Length)
{
return(-1);
}
return(0);
}
public static BufLen Decrypt(BufLen data, I2PPrivateKey pkey, bool zeropad)
{
if (data == null || zeropad && data.Length != EncryptedPaddedLength)
{
throw new ArgumentException($"ElGamal padded data to decrypt must be exactly {EncryptedPaddedLength} bytes!");
}
if (!zeropad && data.Length != EncryptedShortLength)
{
throw new ArgumentException($"ElGamal data to decrypt must be exactly {EncryptedShortLength} bytes!");
}
var x = I2PConstants.ElGamalPMinusOne.Subtract(pkey.ToBigInteger());
var reader = new BufRefLen(data);
var readlen = zeropad
? EncryptedPaddedLength / 2
: EncryptedShortLength / 2;
var a = reader.ReadBigInteger(readlen);
var b = reader.ReadBigInteger(readlen);
var m2 = b.Multiply(a.ModPow(x, I2PConstants.ElGamalP));
var m1 = m2.Mod(I2PConstants.ElGamalP);
var m = m1.ToByteArrayUnsigned();
var payload = new BufLen(m, 33, ClearTextLength);
var hash = I2PHashSHA256.GetHash(payload);
if (!BufUtils.Equal(m, 1, hash, 0, 32))
{
throw new HashCheckFailException();
}
return(payload);
}
public static BufLen BCGZipDecompressNew(BufLen buf)
{
var reader = new BufRefLen(buf);
// Skip gzip header
var gzheader = reader.ReadBufLen(10);
var flag = gzheader.Peek8(3);
if ((flag & 0x04) != 0)
{
reader.Seek(reader.Read16()); // "Extra"
}
if ((flag & 0x08) != 0)
{
while (reader.Read8() != 0)
{
; // "Name"
}
}
if ((flag & 0x10) != 0)
{
while (reader.Read8() != 0)
{
; // "Comment"
}
}
if ((flag & 0x02) != 0)
{
reader.Read16(); // "CRC16"
}
var z = new ZStream();
z.inflateInit(true);
var dest = new byte[buf.Length * 2];
var destix = 0;
z.next_in_index = reader.BaseArrayOffset;
z.next_in = reader.BaseArray;
z.avail_in = reader.Length - 8;
bigger_dest:
z.next_out = dest;
z.next_out_index = destix;
z.avail_out = dest.Length - destix;
var err = z.inflate(JZlib.Z_FINISH);
if (err != JZlib.Z_BUF_ERROR && err != JZlib.Z_OK && err != JZlib.Z_STREAM_END)
{
throw new IOException("inflating: " + z.msg);
}
if (z.avail_out == 0)
{
var newdest = new byte[dest.Length * 2];
Array.Copy(dest, newdest, dest.Length);
destix = dest.Length;
dest = newdest;
goto bigger_dest;
}
var result = new BufLen(dest, 0, dest.Length - z.avail_out);
z.inflateEnd();
return(result);
}
int IComparable <BufRefLen> .CompareTo(BufRefLen other)
{
return(Compare(this, other));
}
public BufLen(BufRefLen src, int offset, int len) : base(src, offset)
{
LengthDef = Math.Min(len, src.Length - offset);
}
public static void Randomize(this BufRefLen buf)
{
Rnd.NextBytes(buf.BaseArray, buf.BaseArrayOffset, buf.Length);
}
public BufLen(BufRefLen src, int offset) : base(src, offset)
{
LengthDef = src.Length - offset;
}
public BufLen(BufRefLen src) : base(src)
{
LengthDef = src.Length;
}
public static byte[] Decode(string data)
{
if (data.Length < 4 || data.Length % 4 != 0)
{
throw new FormatException("FreenetBase64 string needs to be padded to 4 byte align!");
}
var size = 3 * (data.Length / 4);
if (data[data.Length - 1] == '=')
{
--size;
}
if (data[data.Length - 2] == '=')
{
--size;
}
if (data[data.Length - 3] == '=')
{
--size;
}
var result = new byte[size];
if (Codomain == null)
{
Codomain = new int[256];
for (int i = 0; i < 256; ++i)
{
Codomain[i] = -1;
}
for (int i = 0; i < 64; ++i)
{
Codomain[(byte)Domain[i]] = i;
}
Codomain[(byte)'='] = 0;
}
byte v1, v2;
var reader = data.GetEnumerator();
reader.MoveNext();
var writer = new BufRefLen(result);
for (int i = 0; i < data.Length / 4; ++i)
{
v1 = Lookup(reader);
v2 = Lookup(reader);
v1 <<= 2;
v1 |= (byte)(v2 >> 4);
writer.Write8(v1);
if (writer.Length == 0)
{
break;
}
v2 <<= 4;
v1 = Lookup(reader);
v2 |= (byte)(v1 >> 2);
writer.Write8(v2);
if (writer.Length == 0)
{
break;
}
v2 = Lookup(reader);
v2 |= (byte)(v1 << 6);
writer.Write8(v2);
if (writer.Length == 0)
{
break;
}
}
return(result);
}
public BufRefLen(BufRefLen src, int offset, int len) : base(src, offset)
{
LengthDef = Math.Min(len, src.BaseArray.Length - src.BaseArrayOffset - offset);
}
public void Poke(BufRefLen src, int offset)
{
PreWriteCheck(offset + src.Length);
Array.Copy(src.Data, src.Position, Data, Position + offset, src.Length);
}
