X-Git-Url: https://git.cryptolib.org/?a=blobdiff_plain;f=grain%2Fgrain.c;h=fc8c7f7670a968d54c9bffd087b4100246988f8a;hb=eb0cafe05ab4cdf60878dbd81e4ff3712d5150f2;hp=8d30d2266299a367a2f5891daa0220f58642fe2d;hpb=d32eba56ce10ea6b9eff123b50d9842673b38f2b;p=avr-crypto-lib.git

diff --git a/grain/grain.c b/grain/grain.c
index 8d30d22..fc8c7f7 100644
--- a/grain/grain.c
+++ b/grain/grain.c
@@ -40,10 +40,10 @@
 #define _B(i) (((ctx->nfsr[9-((i)/8)])>>(7-((i)%8)))&1)
 
 
-uint8_t h_lut[4] PROGMEM = {0x4C, 0xB6, 0xD3, 0x26};
+const uint8_t h_lut[4] PROGMEM = {0x4C, 0xB6, 0xD3, 0x26};
 
 #ifdef GRAIN_BADOPTIMISATION
-uint8_t g_lut[128] PROGMEM = {
+const uint8_t g_lut[128] PROGMEM = {
         0xF0, 0xA5, 0x0F, 0x5A, 0x0F, 0x5A, 0xF0, 0xA5, 0x0F, 0x5A, 0xF0, 0xA5, 0xF0, 0x5A, 0x0F, 0x0F, 
         0xC3, 0x96, 0x3C, 0x69, 0x3C, 0x69, 0xC3, 0x96, 0x9C, 0xC9, 0x63, 0x36, 0x63, 0xC9, 0x9C, 0x9C, 
         0x0F, 0x5A, 0x0F, 0x5A, 0xF0, 0xA5, 0xF0, 0x5A, 0xF0, 0xA5, 0xF0, 0xA5, 0x0F, 0xA5, 0x0F, 0xF0, 
@@ -54,7 +54,7 @@ uint8_t g_lut[128] PROGMEM = {
         0xF3, 0x2E, 0xF3, 0x2E, 0x0C, 0xD1, 0x0C, 0x2E, 0xAC, 0x71, 0xAC, 0x71, 0x53, 0x71, 0xA3, 0xD4  };
 #endif
 
-uint8_t grain_enc(grain_ctx_t* ctx){
+uint8_t grain_enc(grain_ctx_t *ctx){
 	uint8_t s80, s0, c1, c2;
 	uint8_t i;
 	/* clock the LFSR */
@@ -134,7 +134,17 @@ uint8_t grain_enc(grain_ctx_t* ctx){
 	h = (pgm_read_byte(h_lut+(i/8)))>>(i%8);
 	
 	h ^= B(0) ^ B(1) ^ B(3) ^ B(9) ^ B(30) ^ B(42) ^ B(55);
-	return h&1;
+	return (h&1);
+}
+
+uint8_t grain_getbyte(grain_ctx_t *ctx){
+	uint8_t i=0;
+	uint8_t r=0;
+	do{
+		r >>= 1;
+		r |= grain_enc(ctx)?0x80:0x00;
+	}while(++i<8);
+	return r;
 }
 
 #ifdef GRAIN_REVERSEKEY
@@ -156,7 +166,7 @@ uint8_t reverse_bits(uint8_t a){
 
 #endif
 
-void grain_init(const void* key, const void* iv, grain_ctx_t* ctx){
+void grain_init(const void *key, const void *iv, grain_ctx_t *ctx){
 	uint8_t i,t;
 	
 	/* load the 80bit key */