forgotten directories

[avr-crypto-lib.git] / noekeon / omac_noekeon_C.c

diff --git a/noekeon/omac_noekeon_C.c b/noekeon/omac_noekeon_C.c
new file mode 100644 (file)
index 0000000..923fc48
--- /dev/null
+++ b/noekeon/omac_noekeon_C.c
@@ -0,0 +1,74 @@
+#include "noekeon/noekeon.h"
+#include "omac_noekeon.h"
+#include "memxor/memxor.h"
+#include <string.h>
+#include <stdint.h>
+
+
+void omac_noekeon_init(omac_noekeon_ctx_t* ctx){
+       memset(ctx, 0, 16);
+}
+
+
+void omac_noekeon_tweak(uint8_t t, const void* key, omac_noekeon_ctx_t* ctx){
+       *ctx[15] = t;
+       noekeon_enc(ctx, key);
+}
+
+void omac_noekeon_next(const void* buffer, const void* key, omac_noekeon_ctx_t* ctx){
+       memxor(ctx, buffer, 16);
+       noekeon_enc(ctx, key);
+}
+
+static
+void omac_noekeon_comppad(uint8_t* pad, const void* key, uint8_t length_b){
+       uint8_t c1,c2,r,j;
+       memset(pad, 0, 16);
+       noekeon_enc(pad, key);
+       r=(length_b==128)?1:2;
+       for(;r!=0;--r){
+               c1=0;
+               for(j=0;j<16;++j){
+                       c2 = c1;
+                       c1 = (pad[15-j])>>7;
+                       pad[15-j] = ((pad[15-j])<<1) | c2;
+               }
+               if(c1){
+                       pad[15] ^= 0x87;
+               }
+       }
+       if(length_b<128){
+               pad[(length_b)/8] ^= 0x80 >> (length_b%8);
+       }
+}
+
+void omac_noekeon_last(const void* buffer, uint8_t length_b, const void* key, omac_noekeon_ctx_t* ctx){
+       while(length_b>128){
+               omac_noekeon_next(buffer, key, ctx);
+               buffer = (uint8_t*)buffer +16;
+               length_b -= 128;
+       }
+       uint8_t pad[16];
+       omac_noekeon_comppad(pad, key, length_b);
+       memxor(pad, buffer, (length_b+7)/8);
+       omac_noekeon_next(pad, key, ctx);
+}
+
+
+void omac_noekeon(void* dest, const void* msg, uint16_t msglength_b,
+                  const void* key, uint8_t t){
+       omac_noekeon_init(dest);
+       if(t!=0xff)
+               omac_noekeon_tweak(t,key,dest);
+       while(msglength_b>128){
+               omac_noekeon_next(msg, key, dest);
+               msg = (uint8_t*)msg +16;
+               msglength_b -= 128;
+       }
+       omac_noekeon_last(msg, msglength_b, key, dest);                         
+}
+
+
+
+
+