1// rc2.cpp - written and placed in the public domain by Wei Dai 2 3#include "pch.h" 4#include "rc2.h" 5#include "misc.h" 6#include "argnames.h" 7 8NAMESPACE_BEGIN(CryptoPP) 9 10void RC2::Base::UncheckedSetKey(const byte *key, unsigned int keyLen, const NameValuePairs ¶ms) 11{ 12 AssertValidKeyLength(keyLen); 13 14 int effectiveLen = params.GetIntValueWithDefault(Name::EffectiveKeyLength(), DEFAULT_EFFECTIVE_KEYLENGTH); 15 if (effectiveLen > MAX_EFFECTIVE_KEYLENGTH) 16 throw InvalidArgument("RC2: effective key length parameter exceeds maximum"); 17 18 static const unsigned char PITABLE[256] = { 19 217,120,249,196, 25,221,181,237, 40,233,253,121, 74,160,216,157, 20 198,126, 55,131, 43,118, 83,142, 98, 76,100,136, 68,139,251,162, 21 23,154, 89,245,135,179, 79, 19, 97, 69,109,141, 9,129,125, 50, 22 189,143, 64,235,134,183,123, 11,240,149, 33, 34, 92,107, 78,130, 23 84,214,101,147,206, 96,178, 28,115, 86,192, 20,167,140,241,220, 24 18,117,202, 31, 59,190,228,209, 66, 61,212, 48,163, 60,182, 38, 25 111,191, 14,218, 70,105, 7, 87, 39,242, 29,155,188,148, 67, 3, 26 248, 17,199,246,144,239, 62,231, 6,195,213, 47,200,102, 30,215, 27 8,232,234,222,128, 82,238,247,132,170,114,172, 53, 77,106, 42, 28 150, 26,210,113, 90, 21, 73,116, 75,159,208, 94, 4, 24,164,236, 29 194,224, 65,110, 15, 81,203,204, 36,145,175, 80,161,244,112, 57, 30 153,124, 58,133, 35,184,180,122,252, 2, 54, 91, 37, 85,151, 49, 31 45, 93,250,152,227,138,146,174, 5,223, 41, 16,103,108,186,201, 32 211, 0,230,207,225,158,168, 44, 99, 22, 1, 63, 88,226,137,169, 33 13, 56, 52, 27,171, 51,255,176,187, 72, 12, 95,185,177,205, 46, 34 197,243,219, 71,229,165,156,119, 10,166, 32,104,254,127,193,173}; 35 36 SecByteBlock L(128); 37 memcpy(L, key, keyLen); 38 39 int i; 40 for (i=keyLen; i<128; i++) 41 L[i] = PITABLE[(L[i-1] + L[i-keyLen]) & 255]; 42 43 unsigned int T8 = (effectiveLen+7) / 8; 44 byte TM = 255 >> ((8-(effectiveLen%8))%8); 45 L[128-T8] = PITABLE[L[128-T8] & TM]; 46 47 for (i=127-T8; i>=0; i--) 48 L[i] = PITABLE[L[i+1] ^ L[i+T8]]; 49 50 for (i=0; i<64; i++) 51 K[i] = L[2*i] + (L[2*i+1] << 8); 52} 53 54typedef BlockGetAndPut<word16, LittleEndian> Block; 55 56void RC2::Enc::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const 57{ 58 word16 R0, R1, R2, R3; 59 Block::Get(inBlock)(R0)(R1)(R2)(R3); 60 61 for (int i = 0; i < 16; i++) 62 { 63 R0 += (R1 & ~R3) + (R2 & R3) + K[4*i+0]; 64 R0 = rotlFixed(R0, 1); 65 66 R1 += (R2 & ~R0) + (R3 & R0) + K[4*i+1]; 67 R1 = rotlFixed(R1, 2); 68 69 R2 += (R3 & ~R1) + (R0 & R1) + K[4*i+2]; 70 R2 = rotlFixed(R2, 3); 71 72 R3 += (R0 & ~R2) + (R1 & R2) + K[4*i+3]; 73 R3 = rotlFixed(R3, 5); 74 75 if (i == 4 || i == 10) 76 { 77 R0 += K[R3 & 63]; 78 R1 += K[R0 & 63]; 79 R2 += K[R1 & 63]; 80 R3 += K[R2 & 63]; 81 } 82 } 83 84 Block::Put(xorBlock, outBlock)(R0)(R1)(R2)(R3); 85} 86 87void RC2::Dec::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const 88{ 89 word16 R0, R1, R2, R3; 90 Block::Get(inBlock)(R0)(R1)(R2)(R3); 91 92 for (int i = 15; i >= 0; i--) 93 { 94 if (i == 4 || i == 10) 95 { 96 R3 -= K[R2 & 63]; 97 R2 -= K[R1 & 63]; 98 R1 -= K[R0 & 63]; 99 R0 -= K[R3 & 63]; 100 } 101 102 R3 = rotrFixed(R3, 5); 103 R3 -= (R0 & ~R2) + (R1 & R2) + K[4*i+3]; 104 105 R2 = rotrFixed(R2, 3); 106 R2 -= (R3 & ~R1) + (R0 & R1) + K[4*i+2]; 107 108 R1 = rotrFixed(R1, 2); 109 R1 -= (R2 & ~R0) + (R3 & R0) + K[4*i+1]; 110 111 R0 = rotrFixed(R0, 1); 112 R0 -= (R1 & ~R3) + (R2 & R3) + K[4*i+0]; 113 } 114 115 Block::Put(xorBlock, outBlock)(R0)(R1)(R2)(R3); 116} 117 118NAMESPACE_END 119