--- /dev/null
+/* serpent.c
+ * a bitsliced implementation of the serpent cipher for avr microcontrollers
+ * author: Daniel Otte
+ * license: GPLv3
+ */
+
+#include <stdint.h>
+#include <string.h> /* memset() */
+#include <avr/pgmspace.h>
+
+#include "uart.h"
+#include "debug.h"
+
+
+/*
+ S0: 3 8 15 1 10 6 5 11 14 13 4 2 7 0 9 12
+ S1: 15 12 2 7 9 0 5 10 1 11 14 8 6 13 3 4
+ S2: 8 6 7 9 3 12 10 15 13 1 14 4 0 11 5 2
+ S3: 0 15 11 8 12 9 6 3 13 1 2 4 10 7 5 14
+ S4: 1 15 8 3 12 0 11 6 2 5 4 10 9 14 7 13
+ S5: 15 5 2 11 4 10 9 12 0 3 14 8 13 6 7 1
+ S6: 7 2 12 5 8 4 6 11 14 9 1 15 13 3 10 0
+ S7: 1 13 15 0 14 8 2 11 7 4 12 10 9 3 5 6
+*/
+
+uint8_t sbox[] PROGMEM = {
+ 0x38, 0xF1, 0xA6, 0x5B, 0xED, 0x42, 0x70, 0x9C,
+ 0xFC, 0x27, 0x90, 0x5A, 0x1B, 0xE8, 0x6D, 0x34,
+ 0x86, 0x79, 0x3C, 0xAF, 0xD1, 0xE4, 0x0B, 0x52,
+ 0x0F, 0xB8, 0xC9, 0x63, 0xD1, 0x24, 0xA7, 0x5E,
+ 0x1F, 0x83, 0xC0, 0xB6, 0x25, 0x4A, 0x9E, 0x7D,
+ 0xF5, 0x2B, 0x4A, 0x9C, 0x03, 0xE8, 0xD6, 0x71,
+ 0x72, 0xC5, 0x84, 0x6B, 0xE9, 0x1F, 0xD3, 0xA0,
+ 0x1D, 0xF0, 0xE8, 0x2B, 0x74, 0xCA, 0x93, 0x56,
+/* now the inverted sboxes */
+ 0xD3, 0xB0, 0xA6, 0x5C, 0x1E, 0x47, 0xF9, 0x82,
+ 0x58, 0x2E, 0xF6, 0xC3, 0xB4, 0x79, 0x1D, 0xA0,
+ 0xC9, 0xF4, 0xBE, 0x12, 0x03, 0x6D, 0x58, 0xA7,
+ 0x09, 0xA7, 0xBE, 0x6D, 0x35, 0xC2, 0x48, 0xF1,
+ 0x50, 0x83, 0xA9, 0x7E, 0x2C, 0xB6, 0x4F, 0xD1,
+ 0x8F, 0x29, 0x41, 0xDE, 0xB6, 0x53, 0x7C, 0xA0,
+ 0xFA, 0x1D, 0x53, 0x60, 0x49, 0xE7, 0x2C, 0x8B,
+ 0x30, 0x6D, 0x9E, 0xF8, 0x5C, 0xB7, 0xA1, 0x42
+};
+
+/*
+ InvS0: 13 3 11 0 10 6 5 12 1 14 4 7 15 9 8 2
+ InvS1: 5 8 2 14 15 6 12 3 11 4 7 9 1 13 10 0
+ InvS2: 12 9 15 4 11 14 1 2 0 3 6 13 5 8 10 7
+ InvS3: 0 9 10 7 11 14 6 13 3 5 12 2 4 8 15 1
+ InvS4: 5 0 8 3 10 9 7 14 2 12 11 6 4 15 13 1
+ InvS5: 8 15 2 9 4 1 13 14 11 6 5 3 7 12 10 0
+ InvS6: 15 10 1 13 5 3 6 0 4 9 14 7 2 12 8 11
+ InvS7: 3 0 6 13 9 14 15 8 5 12 11 7 10 1 4 2
+*/
+/*
+uint8_t invsbox[] PROGMEM = {
+ 0xD3, 0xB0, 0xA6, 0x5C, 0x1E, 0x47, 0xF9, 0x82,
+ 0x58, 0x2E, 0xF6, 0xC3, 0xB4, 0x79, 0x1D, 0xA0,
+ 0xC9, 0xF4, 0xBE, 0x12, 0x03, 0x6D, 0x58, 0xA7,
+ 0x09, 0xA7, 0xBE, 0x6D, 0x35, 0xC2, 0x48, 0xF1,
+ 0x50, 0x83, 0xA9, 0x7E, 0x2C, 0xB6, 0x4F, 0xD1,
+ 0x8F, 0x29, 0x41, 0xDE, 0xB6, 0x53, 0x7C, 0xA0,
+ 0xFA, 0x1D, 0x53, 0x60, 0x49, 0xE7, 0x2C, 0x8B,
+ 0x30, 0x6D, 0x9E, 0xF8, 0x5C, 0xB7, 0xA1, 0x42
+}
+*/
+
+static uint8_t byteflip(uint8_t v){
+ uint8_t tab[] = { 0x0, 0x8, 0x4, 0xC,
+ 0x2, 0xA, 0x6, 0xE,
+ 0x1, 0x9, 0x5, 0xD,
+ 0x3, 0xB, 0x7, 0xF };
+ uint8_t ret;
+ ret = ((tab[v&0xf]) << 4) | tab[v>>4];
+ return ret;
+}
+
+static uint8_t getbit(void* b, uint8_t addr){
+ uint8_t t;
+ t = ((uint8_t*)b)[addr/8];
+ t = (t&(1<<(addr&0x7)))?1:0;
+ return t;
+}
+
+static void setbit(void* b, uint8_t addr, uint8_t v){
+ uint8_t t;
+ t = ((uint8_t*)b)[addr/8];
+ if(v){
+ t |= 1<<(addr&0x7);
+ } else {
+ t &= ~(1<<(addr&0x7));
+ }
+ ((uint8_t*)b)[addr/8] = t;
+}
+/*
+uint8_t ip_table[] PROGMEM = {
+ 0, 32, 64, 96, 1, 33, 65, 97, 2, 34, 66, 98, 3, 35, 67, 99,
+ 4, 36, 68, 100, 5, 37, 69, 101, 6, 38, 70, 102, 7, 39, 71, 103,
+ 8, 40, 72, 104, 9, 41, 73, 105, 10, 42, 74, 106, 11, 43, 75, 107,
+ 12, 44, 76, 108, 13, 45, 77, 109, 14, 46, 78, 110, 15, 47, 79, 111,
+ 16, 48, 80, 112, 17, 49, 81, 113, 18, 50, 82, 114, 19, 51, 83, 115,
+ 20, 52, 84, 116, 21, 53, 85, 117, 22, 54, 86, 118, 23, 55, 87, 119,
+ 24, 56, 88, 120, 25, 57, 89, 121, 26, 58, 90, 122, 27, 59, 91, 123,
+ 28, 60, 92, 124, 29, 61, 93, 125, 30, 62, 94, 126, 31, 63, 95, 127
+};
+* /
+uint8_t fp_table[] PROGMEM = {
+ 0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52, 56, 60,
+ 64, 68, 72, 76, 80, 84, 88, 92, 96, 100, 104, 108, 112, 116, 120, 124,
+ 1, 5, 9, 13, 17, 21, 25, 29, 33, 37, 41, 45, 49, 53, 57, 61,
+ 65, 69, 73, 77, 81, 85, 89, 93, 97, 101, 105, 109, 113, 117, 121, 125,
+ 2, 6, 10, 14, 18, 22, 26, 30, 34, 38, 42, 46, 50, 54, 58, 62,
+ 66, 70, 74, 78, 82, 86, 90, 94, 98, 102, 106, 110, 114, 118, 122, 126,
+ 3, 7, 11, 15, 19, 23, 27, 31, 35, 39, 43, 47, 51, 55, 59, 63,
+ 67, 71, 75, 79, 83, 87, 91, 95, 99, 103, 107, 111, 115, 119, 123, 127
+};
+*/
+/*
+static void ip_stupid(void* out, void* in){
+ uint8_t i,x,t;
+ for(i=0; i<128; ++i){
+ t = pgm_read_byte(ip_table + i);
+ x = getbit(in, t);
+ setbit(out, i, x);
+ }
+}
+*/
+/*
+static void fp_stupid(void* out, void* in){
+ uint8_t i,x,t;
+ for(i=0; i<128; ++i){
+ t = pgm_read_byte(fp_table + i);
+ x = getbit(in, t);
+ setbit(out, i, x);
+ }
+}
+*/
+/* this is a implementation of the needed propertys only! */
+#define SHR_O(a) c=(a)&1; ((a) = (a)>>1)
+#define SHR_I(a) ((a) = (c?0x80:0x00)| ((a)>>1))
+
+static void ip(uint8_t *o, uint32_t *i){
+ uint8_t c; // carry
+ uint8_t n,m;
+ memset(o, 0, 16);
+ for(n=0; n<16; ++n){
+ for(m=0; m<2; ++m){
+ SHR_O(i[0]);
+ SHR_I(o[n]);
+ SHR_O(i[1]);
+ SHR_I(o[n]);
+ SHR_O(i[2]);
+ SHR_I(o[n]);
+ SHR_O(i[3]);
+ SHR_I(o[n]);
+ }
+ }
+}
+
+#undef SHR_I
+#define SHR_I(a) ((a) = (c?0x80000000L:0x00L)| ((a)>>1)) /* we use 32-bit words here */
+
+
+static void fp(uint32_t *o, uint32_t *i){
+ uint8_t c; // carry
+ uint8_t n,m;
+ memset(o, 0, 16);
+ for(n=0; n<4; ++n){
+ for(m=0; m<8; ++m){
+ SHR_O(i[n]);
+ SHR_I(o[0]);
+ SHR_O(i[n]);
+ SHR_I(o[1]);
+ SHR_O(i[n]);
+ SHR_I(o[2]);
+ SHR_O(i[n]);
+ SHR_I(o[3]);
+ }
+ }
+}
+
+/******************************************************************************/
+
+static void sbox128x(uint8_t box, void* w){
+ uint8_t sb[16];
+ uint8_t i,t,x;
+ box &= 0x0f;
+ /* load sbox */
+ for(i=0; i<8; ++i){
+ t = pgm_read_byte(sbox + box*8 + i);
+ sb[2*i+0]=t>>4;
+ sb[2*i+1]=t&0xf;
+ }
+ uint8_t o[16];
+ ip(o, w);
+
+ for(i=0; i<16; ++i){
+ t = ((uint8_t*)o)[i];
+ x = sb[t>>4];
+ x <<= 4;
+ x |= sb[t&0xf];
+ ((uint8_t*)o)[i] = x;
+ }
+ fp(w, o);
+}
+
+static void sbox128(void * w, uint8_t box){
+ sbox128x(box&0x7, w);
+}
+
+static void inv_sbox128(void * w, uint8_t box){
+ sbox128x(((box&0x7)|0x8), w);
+}
+
+/******************************************************************************/
+
+void memxor(void * dest, void * src, uint8_t size){
+ while(size--){
+ *((uint8_t*)dest) ^= *((uint8_t*)src);
+ dest = (uint8_t*)dest +1;
+ src = (uint8_t*)src +1;
+ }
+}
+
+/******************************************************************************/
+
+uint32_t rotl32(uint32_t a, uint8_t n){
+ return ((a<<n) | (a>>(32-n)));
+}
+
+
+uint32_t rotr32(uint32_t a, uint8_t n){
+ return ((a>>n) | (a<<(32-n)));
+}
+
+
+#define X0 (((uint32_t*)b)[0])
+#define X1 (((uint32_t*)b)[1])
+#define X2 (((uint32_t*)b)[2])
+#define X3 (((uint32_t*)b)[3])
+
+static void lt(uint8_t *b){
+ X0 = rotl32(X0, 13);
+ X2 = rotl32(X2, 3);
+ X1 ^= X0 ^ X2;
+ X3 ^= X2 ^ (X0 << 3);
+ X1 = rotl32(X1, 1);
+ X3 = rotl32(X3, 7);
+ X0 ^= X1 ^ X3;
+ X2 ^= X3 ^ (X1 << 7);
+ X0 = rotl32(X0, 5);
+ X2 = rotr32(X2, 10);
+}
+
+static void inv_lt(uint8_t *b){
+ X2 = rotl32(X2, 10);
+ X0 = rotr32(X0, 5);
+ X2 ^= X3 ^ (X1 << 7);
+ X0 ^= X1 ^ X3;
+ X3 = rotr32(X3, 7);
+ X1 = rotr32(X1, 1);
+ X3 ^= X2 ^ (X0 << 3);
+ X1 ^= X0 ^ X2;
+ X2 = rotr32(X2, 3);
+ X0 = rotr32(X0, 13);
+}
+
+typedef uint32_t serpent_subkey_t[4];
+
+typedef struct serpent_ctx_st {
+ serpent_subkey_t k[33];
+} serpent_ctx_t;
+
+
+#define GOLDEN_RATIO 0x9e3779b9l
+
+static uint32_t gen_w(uint32_t * b, uint8_t i){
+ uint32_t ret;
+ ret = b[0] ^ b[3] ^ b[5] ^ b[7] ^ GOLDEN_RATIO ^ (uint32_t)i;
+ ret = rotl32(ret, 11);
+ return ret;
+}
+
+/* key must be 256bit (32 byte) large! */
+void serpent_genctx(void * key, serpent_ctx_t * ctx){
+ uint32_t buffer[8];
+ uint8_t i,j;
+ memcpy(buffer, key, 32);
+ for(i=0; i<33; ++i){
+ for(j=0; j<4; ++j){
+ ctx->k[i][j] = gen_w(buffer, i*4+j);
+ memmove(buffer, &(buffer[1]), 7*4); /* shift buffer one to the "left" */
+ buffer[7] = ctx->k[i][j];
+/*
+ uart_putstr("\r\n w[");
+ uart_putc('0'+(4*i+j)/100);
+ uart_putc('0'+((4*i+j)/10)%10);
+ uart_putc('0'+(4*i+j)%10);
+ uart_putstr("] = ");
+ uart_hexdump(&(ctx->k[i][j]), 4);
+*/
+ }
+ }
+ for(i=0; i<33; ++i){
+ sbox128(ctx->k[i],3-i);
+ }
+}
+
+
+void serpent_enc(void* buffer, serpent_ctx_t * ctx){
+ uint8_t i;
+ for(i=0; i<31; ++i){
+ memxor((uint8_t*)buffer, ctx->k[i], 16);
+ sbox128(buffer, i);
+ lt((uint8_t*)buffer);
+ }
+ memxor((uint8_t*)buffer, ctx->k[i], 16);
+ sbox128(buffer, i);
+ ++i;
+ memxor((uint8_t*)buffer, ctx->k[i], 16);
+}
+
+void serpent_dec(void* buffer, serpent_ctx_t * ctx){
+ int8_t i=32;
+
+ memxor((uint8_t*)buffer, ctx->k[i], 16);
+ --i;
+ inv_sbox128(buffer, i);
+ memxor((uint8_t*)buffer, ctx->k[i], 16);
+ --i;
+ for(; i>=0; --i){
+ inv_lt((uint8_t*)buffer);
+ inv_sbox128(buffer, i);
+ memxor((uint8_t*)buffer, ctx->k[i], 16);
+ }
+}
+
+
+
+
+
+
projects / avr-crypto-lib.git / blobdiff