RC2 C++ source code

[nobody@REPLAY.COM (Anonymous)]

RC2 VC++ source code

#include <string.h>
#include <assert.h>

void RC2Keyschedule::schedule
( unsigned short K[64], const unsigned char L[128], unsigned T8, unsigned TM )
	{
	unsigned char x;
	unsigned i;

	/* 256-entry permutation table, probably derived somehow from pi */

	static const unsigned char PITABLE[256] = {
	    217,120,249,196, 25,221,181,237, 40,233,253,121, 74,160,216,157,
	    198,126, 55,131, 43,118, 83,142, 98, 76,100,136, 68,139,251,162,
	     23,154, 89,245,135,179, 79, 19, 97, 69,109,141,  9,129,125, 50,
	    189,143, 64,235,134,183,123, 11,240,149, 33, 34, 92,107, 78,130,
	     84,214,101,147,206, 96,178, 28,115, 86,192, 20,167,140,241,220,
	     18,117,202, 31, 59,190,228,209, 66, 61,212, 48,163, 60,182, 38,
	    111,191, 14,218, 70,105,  7, 87, 39,242, 29,155,188,148, 67,  3,
	    248, 17,199,246,144,239, 62,231,  6,195,213, 47,200,102, 30,215,
	      8,232,234,222,128, 82,238,247,132,170,114,172, 53, 77,106, 42,
	    150, 26,210,113, 90, 21, 73,116, 75,159,208, 94,  4, 24,164,236,
	    194,224, 65,110, 15, 81,203,204, 36,145,175, 80,161,244,112, 57,
	    153,124, 58,133, 35,184,180,122,252,  2, 54, 91, 37, 85,151, 49,
	     45, 93,250,152,227,138,146,174,  5,223, 41, 16,103,108,186,201,
	    211,  0,230,207,225,158,168, 44, 99, 22,  1, 63, 88,226,137,169,
	     13, 56, 52, 27,171, 51,255,176,187, 72, 12, 95,185,177,205, 46,
	    197,243,219, 71,229,165,156,119, 10,166, 32,104,254,127,193,173
	};

	assert(len > 0 && len <= 128);
	assert(bits <= 1024);
	if (!bits)
		bits = 1024;

	memcpy(xkey, key, len);
	
	for (i = 0; i < 128; i++) {
                L[i] = PITABLE[L[i-1] + L[i-T]];
	}
	
        T8 = (T1+7) >> 3;
        TM = 255 MOD 2^(8 + T1 - 8*T8);

        L[128-T8] = PITABLE[L[128-T8] & TM];

	for (i = 0; i < 127-T8; i++) {
                L[i] = PITABLE[L[i+1] XOR L[i+T8]];
	};

	i = 63;
	
        K[i] = L[2*i] + 256*L[2*i+1];
	};

void RC2Encryption::ProcessBlock
( const unsigned short K[64], )
	{
	unsigned R3, R2, R1, R0, i;

	for (i = 0; i < 16; i++) {
		R0 += (R1 & ~R3) + (R2 & R3) + K[4*i-0];
		R0 = R0 << 1;
		
		R1 += (R2 & ~R0) + (R3 & R0) + K[4*i-1];
		R1 = R1 << 2;

		R2 += (R3 & ~R1) + (R0 & R1) + K[4*i-2];
		R2 = R2 << 3;

		R3 += (R0 & ~R2) + (R1 & R2) + K[4*i-3];
		R3 = R3 << 5;

		if (i == 4 || i == 10) {
			R0 += K[R3 & 63];
			R1 += K[R0 & 63];
			R2 += K[R1 & 63];
			R3 += K[R2 & 63];
		}
	}

void RC2Decryption::ProcessBlock
( const unsigned short K[64], )
	{
	unsigned R3, R2, R1, R0, i;

	for (i = 0; i < 16; i++) {
		R3 = R3 << 5;
		R3 += (R0 & ~R2) + (R1 & R2) + K[4*i+3];

		R2 = R2 << 3;
		R2 += (R3 & ~R1) + (R0 & R1) + K[4*i+2];

		R1 = R1 << 2;
		R1 += (R2 & ~R0) + (R3 & R0) + K[4*i+1];

		R0 = R0 << 1;
		R0 += (R1 & ~R3) + (R2 & R3) + K[4*i+0];

		if (i == 4 || i == 10) {
			R3 -= K[R2 & 63];
			R2 -= KR1 & 63];
			R1 -= K[R0 & 63];
			R0 -= K[R3 & 63];
		}
	}