/* just do the OUTPUT stage */
int Skein1024_Output(Skein1024_Ctxt_t *ctx, u08b_t *hashVal)
{
size_t i,n,byteCnt;
u64b_t X[SKEIN1024_STATE_WORDS];
Skein_Assert(ctx->h.bCnt <= SKEIN1024_BLOCK_BYTES,SKEIN_FAIL); /* catch uninitialized context */
/* now output the result */
byteCnt = (ctx->h.hashBitLen + 7) >> 3; /* total number of output bytes */
/* run Threefish in "counter mode" to generate output */
memset(ctx->b,0,sizeof(ctx->b)); /* zero out b[], so it can hold the counter */
memcpy(X,ctx->X,sizeof(X)); /* keep a local copy of counter mode "key" */
for (i=0;i*SKEIN1024_BLOCK_BYTES < byteCnt;i++)
{
((u64b_t *)ctx->b)[0]= Skein_Swap64((u64b_t) i); /* build the counter block */
Skein_Start_New_Type(ctx,OUT_FINAL);
Skein1024_Process_Block(ctx,ctx->b,1,sizeof(u64b_t)); /* run "counter mode" */
n = byteCnt - i*SKEIN1024_BLOCK_BYTES; /* number of output bytes left to go */
if (n >= SKEIN1024_BLOCK_BYTES)
n = SKEIN1024_BLOCK_BYTES;
Skein_Put64_LSB_First(hashVal+i*SKEIN1024_BLOCK_BYTES,ctx->X,n); /* "output" the ctr mode bytes */
Skein_Show_Final(256,&ctx->h,n,hashVal+i*SKEIN1024_BLOCK_BYTES);
memcpy(ctx->X,X,sizeof(X)); /* restore the counter mode key for next time */
}
return SKEIN_SUCCESS;
}
/* finalize the hash computation and output the result */
void skein512::finalize( hash &hashVal )
{
size_t n,byteCnt;
uint64_t Y[8];
_T[1] |= SKEIN_T1_FLAG_FINAL; /* tag as the final block */
if ( _block_size < 64 ) /* zero pad b[] if necessary */
memset( &_block[_block_size], 0, 64 - _block_size );
process( _block, 1, _block_size ); /* process the final block */
/* now output the result */
byteCnt = (512 + 7) >> 3; /* total number of output bytes */
/* run Threefish in "counter mode" to generate output */
memset( _block, 0, sizeof(_block) ); /* zero out b[], so it can hold the counter */
memcpy( Y, _X, sizeof(_X) ); /* keep a local copy of counter mode "key" */
for ( size_t i = 0; i * 64 < byteCnt; i++ )
{
_block64[0] = Skein_Swap64( uint64_t(i) ); /* build the counter block */
start_new_type( SKEIN_T1_BLK_TYPE_OUT_FINAL );
process( _block, 1, sizeof(uint64_t) ); /* run "counter mode" */
n = byteCnt - i*64; /* number of output bytes left to go */
if (n >= 64)
n = 64;
Skein_Put64_LSB_First(hashVal.data()+i*64,_X,n); /* "output" the ctr mode bytes */
memcpy(_X,Y,sizeof(_X)); /* restore the counter mode key for next time */
}
}
/* init the context for a straight hashing operation */
int Skein_512_Init(Skein_512_Ctxt_t *ctx, size_t hashBitLen)
{
union
{
u08b_t b[SKEIN_512_STATE_BYTES];
u64b_t w[SKEIN_512_STATE_WORDS];
} cfg; /* config block */
Skein_Assert(hashBitLen > 0,SKEIN_BAD_HASHLEN);
ctx->h.hashBitLen = hashBitLen; /* output hash bit count */
switch (hashBitLen)
{ /* use pre-computed values, where available */
case 512:
memcpy(ctx->X,SKEIN_512_IV_512,sizeof(ctx->X));
break;
case 384:
memcpy(ctx->X,SKEIN_512_IV_384,sizeof(ctx->X));
break;
case 256:
memcpy(ctx->X,SKEIN_512_IV_256,sizeof(ctx->X));
break;
case 224:
memcpy(ctx->X,SKEIN_512_IV_224,sizeof(ctx->X));
break;
default:
/* here if there is no precomputed IV value available */
/* build/process the config block, type == CONFIG (could be precomputed) */
Skein_Start_New_Type(ctx,CFG_FINAL); /* set tweaks: T0=0; T1=CFG | FINAL */
cfg.w[0] = Skein_Swap64(SKEIN_SCHEMA_VER); /* set the schema, version */
cfg.w[1] = Skein_Swap64(hashBitLen); /* hash result length in bits */
cfg.w[2] = Skein_Swap64(SKEIN_CFG_TREE_INFO_SEQUENTIAL);
memset(&cfg.w[3],0,sizeof(cfg) - 3*sizeof(cfg.w[0])); /* zero pad config block */
/* compute the initial chaining values from config block */
memset(ctx->X,0,sizeof(ctx->X)); /* zero the chaining variables */
Skein_512_Process_Block(ctx,cfg.b,1,SKEIN_CFG_STR_LEN);
break;
}
/* The chaining vars ctx->X are now initialized for the given hashBitLen. */
/* Set up to process the data message portion of the hash (default) */
Skein_Start_New_Type(ctx,MSG); /* T0=0, T1= MSG type */
return SKEIN_SUCCESS;
}
/* finalize the hash computation and output the result */
int
Skein1024_Final(Skein1024_Ctxt_t *ctx, uint8_t *hashVal)
{
size_t i, n, byteCnt;
uint64_t X[SKEIN1024_STATE_WORDS];
/* catch uninitialized context */
Skein_Assert(ctx->h.bCnt <= SKEIN1024_BLOCK_BYTES, SKEIN_FAIL);
ctx->h.T[1] |= SKEIN_T1_FLAG_FINAL; /* tag as the final block */
/* zero pad b[] if necessary */
if (ctx->h.bCnt < SKEIN1024_BLOCK_BYTES)
bzero(&ctx->b[ctx->h.bCnt],
SKEIN1024_BLOCK_BYTES - ctx->h.bCnt);
/* process the final block */
Skein1024_Process_Block(ctx, ctx->b, 1, ctx->h.bCnt);
/* now output the result */
/* total number of output bytes */
byteCnt = (ctx->h.hashBitLen + 7) >> 3;
/* run Threefish in "counter mode" to generate output */
/* zero out b[], so it can hold the counter */
bzero(ctx->b, sizeof (ctx->b));
/* keep a local copy of counter mode "key" */
bcopy(ctx->X, X, sizeof (X));
for (i = 0; i * SKEIN1024_BLOCK_BYTES < byteCnt; i++) {
/* build the counter block */
uint64_t tmp = Skein_Swap64((uint64_t)i);
bcopy(&tmp, ctx->b, sizeof (tmp));
Skein_Start_New_Type(ctx, OUT_FINAL);
/* run "counter mode" */
Skein1024_Process_Block(ctx, ctx->b, 1, sizeof (uint64_t));
/* number of output bytes left to go */
n = byteCnt - i * SKEIN1024_BLOCK_BYTES;
if (n >= SKEIN1024_BLOCK_BYTES)
n = SKEIN1024_BLOCK_BYTES;
Skein_Put64_LSB_First(hashVal + i * SKEIN1024_BLOCK_BYTES,
ctx->X, n); /* "output" the ctr mode bytes */
Skein_Show_Final(1024, &ctx->h, n,
hashVal + i * SKEIN1024_BLOCK_BYTES);
/* restore the counter mode key for next time */
bcopy(X, ctx->X, sizeof (X));
}
return (SKEIN_SUCCESS);
}
/*
* [identical to Skein_256_Init() when keyBytes == 0 &&
* treeInfo == SKEIN_CFG_TREE_INFO_SEQUENTIAL]
*/
int
Skein_256_InitExt(Skein_256_Ctxt_t *ctx, size_t hashBitLen, uint64_t treeInfo,
const uint8_t *key, size_t keyBytes)
{
union {
uint8_t b[SKEIN_256_STATE_BYTES];
uint64_t w[SKEIN_256_STATE_WORDS];
} cfg; /* config block */
Skein_Assert(hashBitLen > 0, SKEIN_BAD_HASHLEN);
Skein_Assert(keyBytes == 0 || key != NULL, SKEIN_FAIL);
/* compute the initial chaining values ctx->X[], based on key */
if (keyBytes == 0) { /* is there a key? */
/* no key: use all zeroes as key for config block */
bzero(ctx->X, sizeof (ctx->X));
} else { /* here to pre-process a key */
Skein_assert(sizeof (cfg.b) >= sizeof (ctx->X));
/* do a mini-Init right here */
/* set output hash bit count = state size */
ctx->h.hashBitLen = 8 * sizeof (ctx->X);
/* set tweaks: T0 = 0; T1 = KEY type */
Skein_Start_New_Type(ctx, KEY);
/* zero the initial chaining variables */
bzero(ctx->X, sizeof (ctx->X));
/* hash the key */
(void) Skein_256_Update(ctx, key, keyBytes);
/* put result into cfg.b[] */
(void) Skein_256_Final_Pad(ctx, cfg.b);
/* copy over into ctx->X[] */
bcopy(cfg.b, ctx->X, sizeof (cfg.b));
#if SKEIN_NEED_SWAP
{
uint_t i;
/* convert key bytes to context words */
for (i = 0; i < SKEIN_256_STATE_WORDS; i++)
ctx->X[i] = Skein_Swap64(ctx->X[i]);
}
#endif
}
/*
* build/process the config block, type == CONFIG (could be
* precomputed for each key)
*/
ctx->h.hashBitLen = hashBitLen; /* output hash bit count */
Skein_Start_New_Type(ctx, CFG_FINAL);
bzero(&cfg.w, sizeof (cfg.w)); /* pre-pad cfg.w[] with zeroes */
cfg.w[0] = Skein_Swap64(SKEIN_SCHEMA_VER);
cfg.w[1] = Skein_Swap64(hashBitLen); /* hash result length in bits */
/* tree hash config info (or SKEIN_CFG_TREE_INFO_SEQUENTIAL) */
cfg.w[2] = Skein_Swap64(treeInfo);
Skein_Show_Key(256, &ctx->h, key, keyBytes);
/* compute the initial chaining values from config block */
Skein_256_Process_Block(ctx, cfg.b, 1, SKEIN_CFG_STR_LEN);
/* The chaining vars ctx->X are now initialized */
/* Set up to process the data message portion of the hash (default) */
ctx->h.bCnt = 0; /* buffer b[] starts out empty */
Skein_Start_New_Type(ctx, MSG);
return (SKEIN_SUCCESS);
}
