#define K(s) (((uint64_t*)key)[(s)])
#define T(s) (((uint64_t*)tweak)[(s)])
-void threefish256_init(void* key, void* tweak, threefish256_ctx_t* ctx){
+void threefish256_init(const void* key, const void* tweak, threefish256_ctx_t* ctx){
memcpy(ctx->k, key, 4*8);
- memcpy(ctx->t, tweak, 2*8);
+ if(tweak){
+ memcpy(ctx->t, tweak, 2*8);
+ ctx->t[2] = T(0) ^ T(1);
+ }else{
+ memset(ctx->t, 0, 3*8);
+ }
uint8_t i;
ctx->k[4] = THREEFISH_KEY_CONST;
for(i=0; i<4; ++i){
ctx->k[4] ^= K(i);
}
- ctx->t[2] = T(0) ^ T(1);
}
static
-void add_key_4(void* data, threefish256_ctx_t* ctx, uint8_t s){
+void add_key_4(void* data, const threefish256_ctx_t* ctx, uint8_t s){
X(0) += ctx->k[(s+0)%5];
X(1) += ctx->k[(s+1)%5] + ctx->t[s%3];
X(2) += ctx->k[(s+2)%5] + ctx->t[(s+1)%3];
X(3) += ctx->k[(s+3)%5] + s;
}
-void threefish256_enc(void* data, threefish256_ctx_t* ctx){
+void threefish256_enc(void* data, const threefish256_ctx_t* ctx){
uint8_t i=0,s=0;
uint8_t r0[8] = { 5, 36, 13, 58, 26, 53, 11, 59};
uint8_t r1[8] = {56, 28, 46, 44, 20, 35, 42, 50};