even more serpent in asm

diff --git a/serpent-asm.S b/serpent-asm.S
index a16f6af26bf2c97bc028d39b17d104b165ab7fe8..1005fd368b56ac1ceed0735ba90d3e172668cd52 100644 (file)
--- a/serpent-asm.S
+++ b/serpent-asm.S
@@ -538,6 +538,9 @@ static uint32_t serpent_gen_w(uint32_t * b, uint8_t i){
  * param i is passed in r22
  * return value is returned in r22.r23.r24.r25
  */
+ /* trashes:
+  *  r20-r25, r30-r31
+  */
 .global serpent_gen_w
 serpent_gen_w:
        movw r30, r24
@@ -589,3 +592,120 @@ serpent_gen_w:
        brne 1b
        ret
 
+/*
+ * void serpent_init(const void* key, uint16_t keysize_b, serpent_ctx_t* ctx)
+ */
+/*
+ * param key     is passed in r24:r25
+ * param keysize is passed in r22:r23
+ * param ctx     is passed in r20:r21
+ */
+.global serpent_init
+serpent_init:
+    stack_alloc 32
+    adiw r30, 1
+       push_ r30, r31
+    movw r26, r22
+    adiw r26, 7
+    tst r27
+    breq 1f
+       ldi r26, 32
+       rjmp 2f
+1:
+       lsr r26
+       lsr r26
+       lsr r26
+2:     
+       mov r22, r26
+       bst r22, 5 /* store in T if we have to do the "append 1 thing"*/
+       ldi r27, 32
+3:     /* set buffer to zero */
+       st Z+, r1
+       dec r27
+       brne 3b
+       
+       movw r26, r24 /* X points to the key */
+       sbiw r30, 32
+       tst r22
+       breq 5f /* if keylength_b==0 */
+4:     /* copy keybytes to buffer */
+       ld r19, X+
+       st Z+, r19
+       dec r22
+       brne 4b
+5:
+       brts 7f /* if keylength_b == 256 */
+       ldi r18, 0x01
+       andi r22, 0x07
+       brne 6f
+       st Z, r18
+       rjmp 7f
+6:     /* shift the one to the right position */
+       lsl r18
+       dec r22
+       brne 6b
+       or r18, r19
+       st -Z, r18
+7: /* post "appending 1 thing" buffer is ready for subkey generation */
+       movw r26, r20  /* X points to the context */
+       
+       pop_ r19, r18 /* r18:r19 points to the buffer */
+       push r16
+       clr r16
+8:
+       movw r24, r18
+       mov  r22, r16
+       rcall serpent_gen_w
+       movw r30, r18
+       ldi r20, 7*4
+1: /* the memmove */
+       ldd r0, Z+4
+       st Z+, r0
+       dec r20
+       brne 1b
+  /* store new word in buffer and context */   
+       st Z+, r22
+       st Z+, r23
+       st Z+, r24
+       st Z+, r25
+       st X+, r22
+       st X+, r23
+       st X+, r24
+       st X+, r25
+       
+       inc r16
+       cpi r16, 132
+       brne 8b 
+       
+       push_ r28, r29
+       movw r28, r26
+       subi r28, lo8(132*4)
+       sbci r29, hi8(132*4)
+       ldi r16, 33
+2:
+       movw r24, r28
+       adiw r28, 16
+       ldi r22, 2
+       add r22, r16
+       rcall sbox128
+       dec r16
+       brne 2b
+       pop_ r29, r28, r16
+       stack_free 32
+       ret
+
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diff --git a/serpent.c b/serpent.c
index 4960664669ec1fe8a4647604b3ac2233434a71fc..7af779dcfaf4deb7e7e26b069992c274c56b68cd 100644 (file)
--- a/serpent.c
+++ b/serpent.c
@@ -91,14 +91,15 @@ static uint32_t serpent_gen_w(uint32_t * b, uint8_t i){
        return ret;
 } 
 */
-void serpent_init(const void* key, uint16_t keysize, serpent_ctx_t* ctx){
+#if 0
+void serpent_init(const void* key, uint16_t keysize_b, serpent_ctx_t* ctx){
        uint32_t buffer[8];
        uint8_t i,j;
-       if(keysize<256){
+       if(keysize_b<256){
                /* keysize is less than 256 bit, padding needed */
                memset(buffer, 0, 32);
-               memcpy(buffer, key, (keysize+7)/8);
-               ((uint8_t*)buffer)[keysize/8] |= 1<<(keysize%8);
+               memcpy(buffer, key, (keysize_b+7)/8);
+               ((uint8_t*)buffer)[keysize_b/8] |= 1<<(keysize_b%8);
        } else {
                /* keysize is 256 bit */
                memcpy(buffer, key, 32); 
@@ -114,7 +115,7 @@ void serpent_init(const void* key, uint16_t keysize, serpent_ctx_t* ctx){
                sbox128(ctx->k[i],3-i);
        }
 }
-
+#endif
 
 void serpent_enc(void* buffer, const serpent_ctx_t* ctx){
        uint8_t i;

diff --git a/serpent.h b/serpent.h
index 3e90253a1aa15556d7483e7d1849e19adfdf2835..f65d36f568dce5ba8f07ee2cb6838f78a63d5d57 100644 (file)
--- a/serpent.h
+++ b/serpent.h
@@ -39,7 +39,7 @@ typedef struct serpent_ctx_st {
 
 
 /* key must be 256bit (32 byte) large! */
-void serpent_init(const void* key, uint16_t keysize, serpent_ctx_t* ctx);
+void serpent_init(const void* key, uint16_t keysize_b, serpent_ctx_t* ctx);
 void serpent_enc(void* buffer, const serpent_ctx_t* ctx);
 void serpent_dec(void* buffer, const serpent_ctx_t* ctx);
 

diff --git a/test_src/main-serpent-test.c b/test_src/main-serpent-test.c
index 5c450b64df58282e38797b46216f5d4a8a279fdc..b4de5f432eff11bfbf461ebceea73f9cb1243980 100644 (file)
--- a/test_src/main-serpent-test.c
+++ b/test_src/main-serpent-test.c
@@ -62,6 +62,19 @@ void testrun_nessie_serpent(void){
        nessie_bc_run();
 }
 
+void testrun_test_serpent(void){
+       uint8_t key[32];
+       serpent_ctx_t ctx;
+       uint8_t i;
+       memset(key, 0, 16);
+       serpent_init(key, 128, &ctx);
+       for(i=0; i<33; ++i){
+               uart_putstr_P(PSTR("\r\n subkekey "));  
+               uart_hexdump(&i, 1);
+               uart_putstr_P(PSTR(" : "));     
+               uart_hexdump(ctx.k[i], 16);
+       }
+}
 
 void testrun_performance_serpent(void){
        uint64_t t;
@@ -114,7 +127,7 @@ int main (void){
        uart_putstr_P(PSTR(")\r\nloaded and running\r\n"));
 
        PGM_P    u   = PSTR("nessie\0test\0performance\0");
-       void_fpt v[] = {testrun_nessie_serpent, testrun_nessie_serpent, testrun_performance_serpent};
+       void_fpt v[] = {testrun_nessie_serpent, testrun_test_serpent, testrun_performance_serpent};
 
        while(1){ 
                if (!getnextwordn(str,20)){DEBUG_S("DBG: W1\r\n"); goto error;}