X-Git-Url: https://git.cryptolib.org/?a=blobdiff_plain;f=threefish256_enc.c;h=8bfbf9de471bad329a6490300d49c25f4e7358b0;hb=55961d766375e8415baf7bc1e74fe9ba087e18ad;hp=afb1a25cdd28886c19cca94c359052d6cac26957;hpb=4147d732efd04605764a2820d4478f33a0cdf1fa;p=avr-crypto-lib.git

diff --git a/threefish256_enc.c b/threefish256_enc.c
index afb1a25..8bfbf9d 100644
--- a/threefish256_enc.c
+++ b/threefish256_enc.c
@@ -44,26 +44,30 @@ void permute_4(void* data){
 #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};