rabbit.c

00001 /* rabbit.c
00002  *
00003  * Copyright (C) 2006-2009 Sawtooth Consulting Ltd.
00004  *
00005  * This file is part of CyaSSL.
00006  *
00007  * CyaSSL is free software; you can redistribute it and/or modify
00008  * it under the terms of the GNU General Public License as published by
00009  * the Free Software Foundation; either version 2 of the License, or
00010  * (at your option) any later version.
00011  *
00012  * CyaSSL is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00015  * GNU General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU General Public License
00018  * along with this program; if not, write to the Free Software
00019  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
00020  */
00021 
00022 
00023 #ifndef NO_RABBIT
00024 
00025 #include "rabbit.h"
00026 #include "misc.c"
00027 
00028 
00029 #ifdef BIG_ENDIAN_ORDER
00030     #define LITTLE32(x) ByteReverseWord32(x)
00031 #else
00032     #define LITTLE32(x) (x)
00033 #endif
00034 
00035 #define U32V(x) (word32)(x)
00036 
00037 
00038 /* Square a 32-bit unsigned integer to obtain the 64-bit result and return */
00039 /* the upper 32 bits XOR the lower 32 bits */
00040 static word32 RABBIT_g_func(word32 x)
00041 {
00042     /* Temporary variables */
00043     word32 a, b, h, l;
00044 
00045     /* Construct high and low argument for squaring */
00046     a = x&0xFFFF;
00047     b = x>>16;
00048 
00049     /* Calculate high and low result of squaring */
00050     h = (((U32V(a*a)>>17) + U32V(a*b))>>15) + b*b;
00051     l = x*x;
00052 
00053     /* Return high XOR low */
00054     return U32V(h^l);
00055 }
00056 
00057 
00058 /* Calculate the next internal state */
00059 static void RABBIT_next_state(RabbitCtx* ctx)
00060 {
00061     /* Temporary variables */
00062     word32 g[8], c_old[8], i;
00063 
00064     /* Save old counter values */
00065     for (i=0; i<8; i++)
00066         c_old[i] = ctx->c[i];
00067 
00068     /* Calculate new counter values */
00069     ctx->c[0] = U32V(ctx->c[0] + 0x4D34D34D + ctx->carry);
00070     ctx->c[1] = U32V(ctx->c[1] + 0xD34D34D3 + (ctx->c[0] < c_old[0]));
00071     ctx->c[2] = U32V(ctx->c[2] + 0x34D34D34 + (ctx->c[1] < c_old[1]));
00072     ctx->c[3] = U32V(ctx->c[3] + 0x4D34D34D + (ctx->c[2] < c_old[2]));
00073     ctx->c[4] = U32V(ctx->c[4] + 0xD34D34D3 + (ctx->c[3] < c_old[3]));
00074     ctx->c[5] = U32V(ctx->c[5] + 0x34D34D34 + (ctx->c[4] < c_old[4]));
00075     ctx->c[6] = U32V(ctx->c[6] + 0x4D34D34D + (ctx->c[5] < c_old[5]));
00076     ctx->c[7] = U32V(ctx->c[7] + 0xD34D34D3 + (ctx->c[6] < c_old[6]));
00077     ctx->carry = (ctx->c[7] < c_old[7]);
00078    
00079     /* Calculate the g-values */
00080     for (i=0;i<8;i++)
00081         g[i] = RABBIT_g_func(U32V(ctx->x[i] + ctx->c[i]));
00082 
00083     /* Calculate new state values */
00084     ctx->x[0] = U32V(g[0] + rotlFixed(g[7],16) + rotlFixed(g[6], 16));
00085     ctx->x[1] = U32V(g[1] + rotlFixed(g[0], 8) + g[7]);
00086     ctx->x[2] = U32V(g[2] + rotlFixed(g[1],16) + rotlFixed(g[0], 16));
00087     ctx->x[3] = U32V(g[3] + rotlFixed(g[2], 8) + g[1]);
00088     ctx->x[4] = U32V(g[4] + rotlFixed(g[3],16) + rotlFixed(g[2], 16));
00089     ctx->x[5] = U32V(g[5] + rotlFixed(g[4], 8) + g[3]);
00090     ctx->x[6] = U32V(g[6] + rotlFixed(g[5],16) + rotlFixed(g[4], 16));
00091     ctx->x[7] = U32V(g[7] + rotlFixed(g[6], 8) + g[5]);
00092 }
00093 
00094 
00095 /* IV setup */
00096 static void RabbitSetIV(Rabbit* ctx, const byte* iv)
00097 {
00098     /* Temporary variables */
00099     word32 i0, i1, i2, i3, i;
00100       
00101     /* Generate four subvectors */
00102     i0 = LITTLE32(*(word32*)(iv+0));
00103     i2 = LITTLE32(*(word32*)(iv+4));
00104     i1 = (i0>>16) | (i2&0xFFFF0000);
00105     i3 = (i2<<16) | (i0&0x0000FFFF);
00106 
00107     /* Modify counter values */
00108     ctx->workCtx.c[0] = ctx->masterCtx.c[0] ^ i0;
00109     ctx->workCtx.c[1] = ctx->masterCtx.c[1] ^ i1;
00110     ctx->workCtx.c[2] = ctx->masterCtx.c[2] ^ i2;
00111     ctx->workCtx.c[3] = ctx->masterCtx.c[3] ^ i3;
00112     ctx->workCtx.c[4] = ctx->masterCtx.c[4] ^ i0;
00113     ctx->workCtx.c[5] = ctx->masterCtx.c[5] ^ i1;
00114     ctx->workCtx.c[6] = ctx->masterCtx.c[6] ^ i2;
00115     ctx->workCtx.c[7] = ctx->masterCtx.c[7] ^ i3;
00116 
00117     /* Copy state variables */
00118     for (i=0; i<8; i++)
00119         ctx->workCtx.x[i] = ctx->masterCtx.x[i];
00120     ctx->workCtx.carry = ctx->masterCtx.carry;
00121 
00122     /* Iterate the system four times */
00123     for (i=0; i<4; i++)
00124         RABBIT_next_state(&(ctx->workCtx));
00125 }
00126 
00127 
00128 /* Key setup */
00129 void RabbitSetKey(Rabbit* ctx, const byte* key, const byte* iv)
00130 {
00131     /* Temporary variables */
00132     word32 k0, k1, k2, k3, i;
00133 
00134     /* Generate four subkeys */
00135     k0 = LITTLE32(*(word32*)(key+ 0));
00136     k1 = LITTLE32(*(word32*)(key+ 4));
00137     k2 = LITTLE32(*(word32*)(key+ 8));
00138     k3 = LITTLE32(*(word32*)(key+12));
00139 
00140     /* Generate initial state variables */
00141     ctx->masterCtx.x[0] = k0;
00142     ctx->masterCtx.x[2] = k1;
00143     ctx->masterCtx.x[4] = k2;
00144     ctx->masterCtx.x[6] = k3;
00145     ctx->masterCtx.x[1] = U32V(k3<<16) | (k2>>16);
00146     ctx->masterCtx.x[3] = U32V(k0<<16) | (k3>>16);
00147     ctx->masterCtx.x[5] = U32V(k1<<16) | (k0>>16);
00148     ctx->masterCtx.x[7] = U32V(k2<<16) | (k1>>16);
00149 
00150     /* Generate initial counter values */
00151     ctx->masterCtx.c[0] = rotlFixed(k2, 16);
00152     ctx->masterCtx.c[2] = rotlFixed(k3, 16);
00153     ctx->masterCtx.c[4] = rotlFixed(k0, 16);
00154     ctx->masterCtx.c[6] = rotlFixed(k1, 16);
00155     ctx->masterCtx.c[1] = (k0&0xFFFF0000) | (k1&0xFFFF);
00156     ctx->masterCtx.c[3] = (k1&0xFFFF0000) | (k2&0xFFFF);
00157     ctx->masterCtx.c[5] = (k2&0xFFFF0000) | (k3&0xFFFF);
00158     ctx->masterCtx.c[7] = (k3&0xFFFF0000) | (k0&0xFFFF);
00159 
00160     /* Clear carry bit */
00161     ctx->masterCtx.carry = 0;
00162 
00163     /* Iterate the system four times */
00164     for (i=0; i<4; i++)
00165         RABBIT_next_state(&(ctx->masterCtx));
00166 
00167     /* Modify the counters */
00168     for (i=0; i<8; i++)
00169         ctx->masterCtx.c[i] ^= ctx->masterCtx.x[(i+4)&0x7];
00170 
00171     /* Copy master instance to work instance */
00172     for (i=0; i<8; i++) {
00173         ctx->workCtx.x[i] = ctx->masterCtx.x[i];
00174         ctx->workCtx.c[i] = ctx->masterCtx.c[i];
00175     }
00176     ctx->workCtx.carry = ctx->masterCtx.carry;
00177 
00178     if (iv) RabbitSetIV(ctx, iv);    
00179 }
00180 
00181 
00182 /* Encrypt/decrypt a message of any size */
00183 void RabbitProcess(Rabbit* ctx, byte* output, const byte* input, word32 msglen)
00184 {
00185 
00186     /* Encrypt/decrypt all full blocks */
00187     while (msglen >= 16) {
00188         /* Iterate the system */
00189         RABBIT_next_state(&(ctx->workCtx));
00190 
00191         /* Encrypt/decrypt 16 bytes of data */
00192         *(word32*)(output+ 0) = *(word32*)(input+ 0) ^
00193                    LITTLE32(ctx->workCtx.x[0] ^ (ctx->workCtx.x[5]>>16) ^
00194                    U32V(ctx->workCtx.x[3]<<16));
00195         *(word32*)(output+ 4) = *(word32*)(input+ 4) ^
00196                    LITTLE32(ctx->workCtx.x[2] ^ (ctx->workCtx.x[7]>>16) ^
00197                    U32V(ctx->workCtx.x[5]<<16));
00198         *(word32*)(output+ 8) = *(word32*)(input+ 8) ^
00199                    LITTLE32(ctx->workCtx.x[4] ^ (ctx->workCtx.x[1]>>16) ^
00200                    U32V(ctx->workCtx.x[7]<<16));
00201         *(word32*)(output+12) = *(word32*)(input+12) ^
00202                    LITTLE32(ctx->workCtx.x[6] ^ (ctx->workCtx.x[3]>>16) ^
00203                    U32V(ctx->workCtx.x[1]<<16));
00204 
00205         /* Increment pointers and decrement length */
00206         input += 16;
00207         output += 16;
00208         msglen -= 16;
00209     }
00210 
00211     /* Encrypt/decrypt remaining data */
00212     if (msglen) {
00213 
00214         word32 i;
00215         word32 tmp[4];
00216         byte*  buffer = (byte*)tmp;
00217 
00218         /* Iterate the system */
00219         RABBIT_next_state(&(ctx->workCtx));
00220 
00221         /* Generate 16 bytes of pseudo-random data */
00222         tmp[0] = LITTLE32(ctx->workCtx.x[0] ^
00223                   (ctx->workCtx.x[5]>>16) ^ U32V(ctx->workCtx.x[3]<<16));
00224         tmp[1] = LITTLE32(ctx->workCtx.x[2] ^ 
00225                   (ctx->workCtx.x[7]>>16) ^ U32V(ctx->workCtx.x[5]<<16));
00226         tmp[2] = LITTLE32(ctx->workCtx.x[4] ^ 
00227                   (ctx->workCtx.x[1]>>16) ^ U32V(ctx->workCtx.x[7]<<16));
00228         tmp[3] = LITTLE32(ctx->workCtx.x[6] ^ 
00229                   (ctx->workCtx.x[3]>>16) ^ U32V(ctx->workCtx.x[1]<<16));
00230 
00231         /* Encrypt/decrypt the data */
00232         for (i=0; i<msglen; i++)
00233             output[i] = input[i] ^ buffer[i];
00234     }
00235 }
00236 
00237 
00238 
00239 #endif /* NO_RABBIT */