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185 lines
5.0 KiB
185 lines
5.0 KiB
/*
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chacha-merged.c version 20080118
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D. J. Bernstein
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Public domain.
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*/
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#include <memory.h>
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#include <stdio.h>
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#ifndef _MSC_VER
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#include <sys/param.h>
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#endif // !_MSC_VER
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#include "chacha8.h"
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#if 0
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#include "common/int-util.h"
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#include "warnings.h"
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#endif
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#if BYTE_ORDER == LITTLE_ENDIAN
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#define SWAP32LE(x) (x)
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#else
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#define SWAP32LE(x) ((((uint32_t) (x) & 0x000000ff) << 24) | \
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(((uint32_t) (x) & 0x0000ff00) << 8) | \
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(((uint32_t) (x) & 0x00ff0000) >> 8) | \
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(((uint32_t) (x) & 0xff000000) >> 24))
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#endif
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/*
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* The following macros are used to obtain exact-width results.
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*/
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#define U8V(v) ((uint8_t)(v) & UINT8_C(0xFF))
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#define U32V(v) ((uint32_t)(v) & UINT32_C(0xFFFFFFFF))
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/*
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* The following macros load words from an array of bytes with
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* different types of endianness, and vice versa.
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*/
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#define U8TO32_LITTLE(p) SWAP32LE(((uint32_t*)(p))[0])
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#define U32TO8_LITTLE(p, v) (((uint32_t*)(p))[0] = SWAP32LE(v))
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#define ROTATE(v,c) (rol32(v,c))
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#define XOR(v,w) ((v) ^ (w))
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#define PLUS(v,w) (U32V((v) + (w)))
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#define PLUSONE(v) (PLUS((v),1))
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#define QUARTERROUND(a,b,c,d) \
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a = PLUS(a,b); d = ROTATE(XOR(d,a),16); \
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c = PLUS(c,d); b = ROTATE(XOR(b,c),12); \
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a = PLUS(a,b); d = ROTATE(XOR(d,a), 8); \
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c = PLUS(c,d); b = ROTATE(XOR(b,c), 7);
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static const char sigma[] = "expand 32-byte k";
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static uint32_t rol32(uint32_t x, int r) {
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return (x << (r & 31)) | (x >> (-r & 31));
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}
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void chacha8(const void* data, size_t length, const uint8_t* key, const uint8_t* iv, char* cipher) {
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uint32_t x0, x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12, x13, x14, x15;
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uint32_t j0, j1, j2, j3, j4, j5, j6, j7, j8, j9, j10, j11, j12, j13, j14, j15;
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char* ctarget = 0;
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char tmp[64];
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int i;
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if (!length) return;
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j0 = U8TO32_LITTLE(sigma + 0);
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j1 = U8TO32_LITTLE(sigma + 4);
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j2 = U8TO32_LITTLE(sigma + 8);
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j3 = U8TO32_LITTLE(sigma + 12);
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j4 = U8TO32_LITTLE(key + 0);
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j5 = U8TO32_LITTLE(key + 4);
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j6 = U8TO32_LITTLE(key + 8);
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j7 = U8TO32_LITTLE(key + 12);
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j8 = U8TO32_LITTLE(key + 16);
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j9 = U8TO32_LITTLE(key + 20);
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j10 = U8TO32_LITTLE(key + 24);
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j11 = U8TO32_LITTLE(key + 28);
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j12 = 0;
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j13 = 0;
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j14 = U8TO32_LITTLE(iv + 0);
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j15 = U8TO32_LITTLE(iv + 4);
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for (;;) {
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if (length < 64) {
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memcpy(tmp, data, length);
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data = tmp;
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ctarget = cipher;
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cipher = tmp;
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}
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x0 = j0;
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x1 = j1;
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x2 = j2;
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x3 = j3;
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x4 = j4;
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x5 = j5;
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x6 = j6;
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x7 = j7;
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x8 = j8;
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x9 = j9;
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x10 = j10;
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x11 = j11;
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x12 = j12;
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x13 = j13;
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x14 = j14;
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x15 = j15;
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for (i = 8;i > 0;i -= 2) {
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QUARTERROUND( x0, x4, x8,x12)
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QUARTERROUND( x1, x5, x9,x13)
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QUARTERROUND( x2, x6,x10,x14)
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QUARTERROUND( x3, x7,x11,x15)
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QUARTERROUND( x0, x5,x10,x15)
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QUARTERROUND( x1, x6,x11,x12)
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QUARTERROUND( x2, x7, x8,x13)
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QUARTERROUND( x3, x4, x9,x14)
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}
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x0 = PLUS( x0, j0);
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x1 = PLUS( x1, j1);
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x2 = PLUS( x2, j2);
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x3 = PLUS( x3, j3);
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x4 = PLUS( x4, j4);
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x5 = PLUS( x5, j5);
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x6 = PLUS( x6, j6);
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x7 = PLUS( x7, j7);
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x8 = PLUS( x8, j8);
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x9 = PLUS( x9, j9);
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x10 = PLUS(x10,j10);
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x11 = PLUS(x11,j11);
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x12 = PLUS(x12,j12);
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x13 = PLUS(x13,j13);
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x14 = PLUS(x14,j14);
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x15 = PLUS(x15,j15);
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x0 = XOR( x0,U8TO32_LITTLE((uint8_t*)data + 0));
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x1 = XOR( x1,U8TO32_LITTLE((uint8_t*)data + 4));
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x2 = XOR( x2,U8TO32_LITTLE((uint8_t*)data + 8));
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x3 = XOR( x3,U8TO32_LITTLE((uint8_t*)data + 12));
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x4 = XOR( x4,U8TO32_LITTLE((uint8_t*)data + 16));
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x5 = XOR( x5,U8TO32_LITTLE((uint8_t*)data + 20));
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x6 = XOR( x6,U8TO32_LITTLE((uint8_t*)data + 24));
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x7 = XOR( x7,U8TO32_LITTLE((uint8_t*)data + 28));
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x8 = XOR( x8,U8TO32_LITTLE((uint8_t*)data + 32));
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x9 = XOR( x9,U8TO32_LITTLE((uint8_t*)data + 36));
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x10 = XOR(x10,U8TO32_LITTLE((uint8_t*)data + 40));
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x11 = XOR(x11,U8TO32_LITTLE((uint8_t*)data + 44));
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x12 = XOR(x12,U8TO32_LITTLE((uint8_t*)data + 48));
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x13 = XOR(x13,U8TO32_LITTLE((uint8_t*)data + 52));
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x14 = XOR(x14,U8TO32_LITTLE((uint8_t*)data + 56));
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x15 = XOR(x15,U8TO32_LITTLE((uint8_t*)data + 60));
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j12 = PLUSONE(j12);
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if (!j12)
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{
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j13 = PLUSONE(j13);
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/* stopping at 2^70 bytes per iv is user's responsibility */
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}
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U32TO8_LITTLE(cipher + 0,x0);
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U32TO8_LITTLE(cipher + 4,x1);
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U32TO8_LITTLE(cipher + 8,x2);
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U32TO8_LITTLE(cipher + 12,x3);
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U32TO8_LITTLE(cipher + 16,x4);
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U32TO8_LITTLE(cipher + 20,x5);
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U32TO8_LITTLE(cipher + 24,x6);
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U32TO8_LITTLE(cipher + 28,x7);
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U32TO8_LITTLE(cipher + 32,x8);
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U32TO8_LITTLE(cipher + 36,x9);
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U32TO8_LITTLE(cipher + 40,x10);
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U32TO8_LITTLE(cipher + 44,x11);
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U32TO8_LITTLE(cipher + 48,x12);
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U32TO8_LITTLE(cipher + 52,x13);
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U32TO8_LITTLE(cipher + 56,x14);
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U32TO8_LITTLE(cipher + 60,x15);
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if (length <= 64) {
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if (length < 64) {
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memcpy(ctarget, cipher, length);
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}
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return;
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}
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length -= 64;
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cipher += 64;
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data = (uint8_t*)data + 64;
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}
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}
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