400 lines
12 KiB
C#
400 lines
12 KiB
C#
#if !BESTHTTP_DISABLE_ALTERNATE_SSL && (!UNITY_WEBGL || UNITY_EDITOR)
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#pragma warning disable
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using System;
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using BestHTTP.SecureProtocol.Org.BouncyCastle.Crypto.Parameters;
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using BestHTTP.SecureProtocol.Org.BouncyCastle.Crypto.Utilities;
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using BestHTTP.SecureProtocol.Org.BouncyCastle.Utilities;
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namespace BestHTTP.SecureProtocol.Org.BouncyCastle.Crypto.Engines
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{
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/**
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* An RC6 engine.
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*/
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public class RC6Engine
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: IBlockCipher
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{
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/*
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* the number of rounds to perform
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*/
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private static readonly int _noRounds = 20;
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/*
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* the expanded key array of size 2*(rounds + 1)
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*/
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private int [] _S;
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/*
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* our "magic constants" for wordSize 32
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*
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* Pw = Odd((e-2) * 2^wordsize)
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* Qw = Odd((o-2) * 2^wordsize)
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*
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* where e is the base of natural logarithms (2.718281828...)
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* and o is the golden ratio (1.61803398...)
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*/
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private static readonly int P32 = unchecked((int) 0xb7e15163);
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private static readonly int Q32 = unchecked((int) 0x9e3779b9);
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private static readonly int LGW = 5; // log2(32)
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private bool forEncryption;
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/**
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* Create an instance of the RC6 encryption algorithm
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* and set some defaults
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*/
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public RC6Engine()
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{
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}
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public virtual string AlgorithmName
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{
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get { return "RC6"; }
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}
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public virtual int GetBlockSize()
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{
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return 16;
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}
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/**
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* initialise a RC5-32 cipher.
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*
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* @param forEncryption whether or not we are for encryption.
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* @param parameters the parameters required to set up the cipher.
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* @exception ArgumentException if the parameters argument is
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* inappropriate.
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*/
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public virtual void Init(bool forEncryption, ICipherParameters parameters)
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{
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if (!(parameters is KeyParameter keyParameter))
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throw new ArgumentException("invalid parameter passed to RC6 init - " + Org.BouncyCastle.Utilities.Platform.GetTypeName(parameters));
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this.forEncryption = forEncryption;
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SetKey(keyParameter.GetKey());
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}
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public virtual int ProcessBlock(byte[] input, int inOff, byte[] output, int outOff)
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{
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if (_S == null)
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throw new InvalidOperationException("RC6 engine not initialised");
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int blockSize = GetBlockSize();
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Check.DataLength(input, inOff, blockSize, "input buffer too short");
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Check.OutputLength(output, outOff, blockSize, "output buffer too short");
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#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER || _UNITY_2021_2_OR_NEWER_
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return forEncryption
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? EncryptBlock(input.AsSpan(inOff), output.AsSpan(outOff))
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: DecryptBlock(input.AsSpan(inOff), output.AsSpan(outOff));
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#else
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return forEncryption
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? EncryptBlock(input, inOff, output, outOff)
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: DecryptBlock(input, inOff, output, outOff);
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#endif
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}
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#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER || _UNITY_2021_2_OR_NEWER_
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public virtual int ProcessBlock(ReadOnlySpan<byte> input, Span<byte> output)
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{
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if (_S == null)
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throw new InvalidOperationException("RC6 engine not initialised");
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int blockSize = GetBlockSize();
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Check.DataLength(input, blockSize, "input buffer too short");
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Check.OutputLength(output, blockSize, "output buffer too short");
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return forEncryption
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? EncryptBlock(input, output)
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: DecryptBlock(input, output);
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}
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#endif
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/**
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* Re-key the cipher.
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*
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* @param inKey the key to be used
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*/
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private void SetKey(
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byte[] key)
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{
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//
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// KEY EXPANSION:
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//
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// There are 3 phases to the key expansion.
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//
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// Phase 1:
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// Copy the secret key K[0...b-1] into an array L[0..c-1] of
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// c = ceil(b/u), where u = wordSize/8 in little-endian order.
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// In other words, we fill up L using u consecutive key bytes
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// of K. Any unfilled byte positions in L are zeroed. In the
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// case that b = c = 0, set c = 1 and L[0] = 0.
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//
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// compute number of dwords
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int c = (key.Length + 3) / 4;
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if (c == 0)
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{
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c = 1;
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}
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int[] L = new int[(key.Length + 3) / 4];
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// load all key bytes into array of key dwords
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for (int i = key.Length - 1; i >= 0; i--)
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{
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L[i / 4] = (L[i / 4] << 8) + (key[i] & 0xff);
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}
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//
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// Phase 2:
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// Key schedule is placed in a array of 2+2*ROUNDS+2 = 44 dwords.
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// Initialize S to a particular fixed pseudo-random bit pattern
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// using an arithmetic progression modulo 2^wordsize determined
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// by the magic numbers, Pw & Qw.
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//
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_S = new int[2+2*_noRounds+2];
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_S[0] = P32;
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for (int i=1; i < _S.Length; i++)
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{
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_S[i] = (_S[i-1] + Q32);
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}
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//
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// Phase 3:
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// Mix in the user's secret key in 3 passes over the arrays S & L.
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// The max of the arrays sizes is used as the loop control
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//
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int iter;
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if (L.Length > _S.Length)
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{
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iter = 3 * L.Length;
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}
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else
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{
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iter = 3 * _S.Length;
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}
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int A = 0;
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int B = 0;
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int ii = 0, jj = 0;
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for (int k = 0; k < iter; k++)
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{
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A = _S[ii] = Integers.RotateLeft(_S[ii] + A + B, 3);
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B = L[jj] = Integers.RotateLeft( L[jj] + A + B, A + B);
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ii = (ii+1) % _S.Length;
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jj = (jj+1) % L.Length;
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}
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}
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#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER || _UNITY_2021_2_OR_NEWER_
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private int EncryptBlock(ReadOnlySpan<byte> input, Span<byte> output)
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{
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// load A,B,C and D registers from in.
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int A = (int)Pack.LE_To_UInt32(input);
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int B = (int)Pack.LE_To_UInt32(input[4..]);
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int C = (int)Pack.LE_To_UInt32(input[8..]);
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int D = (int)Pack.LE_To_UInt32(input[12..]);
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// Do pseudo-round #0: pre-whitening of B and D
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B += _S[0];
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D += _S[1];
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// perform round #1,#2 ... #ROUNDS of encryption
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for (int i = 1; i <= _noRounds; i++)
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{
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int t = 0, u = 0;
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t = B * (2 * B + 1);
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t = Integers.RotateLeft(t, 5);
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u = D * (2 * D + 1);
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u = Integers.RotateLeft(u, 5);
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A ^= t;
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A = Integers.RotateLeft(A, u);
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A += _S[2 * i];
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C ^= u;
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C = Integers.RotateLeft(C, t);
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C += _S[2 * i + 1];
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int temp = A;
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A = B;
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B = C;
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C = D;
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D = temp;
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}
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// do pseudo-round #(ROUNDS+1) : post-whitening of A and C
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A += _S[2 * _noRounds + 2];
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C += _S[2 * _noRounds + 3];
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// store A, B, C and D registers to out
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Pack.UInt32_To_LE((uint)A, output);
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Pack.UInt32_To_LE((uint)B, output[4..]);
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Pack.UInt32_To_LE((uint)C, output[8..]);
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Pack.UInt32_To_LE((uint)D, output[12..]);
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return 16;
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}
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private int DecryptBlock(ReadOnlySpan<byte> input, Span<byte> output)
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{
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// load A,B,C and D registers from out.
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int A = (int)Pack.LE_To_UInt32(input);
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int B = (int)Pack.LE_To_UInt32(input[4..]);
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int C = (int)Pack.LE_To_UInt32(input[8..]);
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int D = (int)Pack.LE_To_UInt32(input[12..]);
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// Undo pseudo-round #(ROUNDS+1) : post whitening of A and C
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C -= _S[2 * _noRounds + 3];
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A -= _S[2 * _noRounds + 2];
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// Undo round #ROUNDS, .., #2,#1 of encryption
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for (int i = _noRounds; i >= 1; i--)
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{
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int t = 0, u = 0;
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int temp = D;
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D = C;
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C = B;
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B = A;
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A = temp;
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t = B * (2 * B + 1);
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t = Integers.RotateLeft(t, LGW);
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u = D * (2 * D + 1);
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u = Integers.RotateLeft(u, LGW);
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C -= _S[2 * i + 1];
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C = Integers.RotateRight(C, t);
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C ^= u;
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A -= _S[2 * i];
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A = Integers.RotateRight(A, u);
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A ^= t;
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}
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// Undo pseudo-round #0: pre-whitening of B and D
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D -= _S[1];
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B -= _S[0];
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Pack.UInt32_To_LE((uint)A, output);
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Pack.UInt32_To_LE((uint)B, output[4..]);
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Pack.UInt32_To_LE((uint)C, output[8..]);
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Pack.UInt32_To_LE((uint)D, output[12..]);
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return 16;
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}
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#else
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private int EncryptBlock(byte[] input, int inOff, byte[] outBytes, int outOff)
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{
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// load A,B,C and D registers from in.
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int A = (int)Pack.LE_To_UInt32(input, inOff);
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int B = (int)Pack.LE_To_UInt32(input, inOff + 4);
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int C = (int)Pack.LE_To_UInt32(input, inOff + 8);
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int D = (int)Pack.LE_To_UInt32(input, inOff + 12);
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// Do pseudo-round #0: pre-whitening of B and D
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B += _S[0];
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D += _S[1];
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// perform round #1,#2 ... #ROUNDS of encryption
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for (int i = 1; i <= _noRounds; i++)
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{
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int t = 0,u = 0;
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t = B*(2*B+1);
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t = Integers.RotateLeft(t,5);
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u = D*(2*D+1);
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u = Integers.RotateLeft(u,5);
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A ^= t;
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A = Integers.RotateLeft(A,u);
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A += _S[2*i];
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C ^= u;
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C = Integers.RotateLeft(C,t);
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C += _S[2*i+1];
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int temp = A;
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A = B;
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B = C;
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C = D;
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D = temp;
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}
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// do pseudo-round #(ROUNDS+1) : post-whitening of A and C
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A += _S[2*_noRounds+2];
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C += _S[2*_noRounds+3];
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// store A, B, C and D registers to out
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Pack.UInt32_To_LE((uint)A, outBytes, outOff);
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Pack.UInt32_To_LE((uint)B, outBytes, outOff + 4);
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Pack.UInt32_To_LE((uint)C, outBytes, outOff + 8);
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Pack.UInt32_To_LE((uint)D, outBytes, outOff + 12);
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return 16;
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}
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private int DecryptBlock(byte[] input, int inOff, byte[] outBytes, int outOff)
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{
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// load A,B,C and D registers from out.
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int A = (int)Pack.LE_To_UInt32(input, inOff);
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int B = (int)Pack.LE_To_UInt32(input, inOff + 4);
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int C = (int)Pack.LE_To_UInt32(input, inOff + 8);
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int D = (int)Pack.LE_To_UInt32(input, inOff + 12);
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// Undo pseudo-round #(ROUNDS+1) : post whitening of A and C
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C -= _S[2*_noRounds+3];
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A -= _S[2*_noRounds+2];
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// Undo round #ROUNDS, .., #2,#1 of encryption
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for (int i = _noRounds; i >= 1; i--)
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{
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int t=0,u = 0;
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int temp = D;
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D = C;
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C = B;
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B = A;
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A = temp;
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t = B*(2*B+1);
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t = Integers.RotateLeft(t, LGW);
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u = D*(2*D+1);
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u = Integers.RotateLeft(u, LGW);
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C -= _S[2*i+1];
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C = Integers.RotateRight(C,t);
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C ^= u;
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A -= _S[2*i];
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A = Integers.RotateRight(A,u);
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A ^= t;
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}
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// Undo pseudo-round #0: pre-whitening of B and D
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D -= _S[1];
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B -= _S[0];
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Pack.UInt32_To_LE((uint)A, outBytes, outOff);
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Pack.UInt32_To_LE((uint)B, outBytes, outOff + 4);
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Pack.UInt32_To_LE((uint)C, outBytes, outOff + 8);
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Pack.UInt32_To_LE((uint)D, outBytes, outOff + 12);
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return 16;
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}
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#endif
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}
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}
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#pragma warning restore
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#endif
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