/* [identical to Skein_512_Init() when keyBytes == 0 && treeInfo == SKEIN_CFG_TREE_INFO_SEQUENTIAL] */
int Skein_512_InitExt(Skein_512_Ctxt_t *ctx,size_t hashBitLen,u64b_t treeInfo, const u08b_t *key, size_t keyBytes)
{
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);
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? */
{
memset(ctx->X,0,sizeof(ctx->X)); /* no key: use all zeroes as key for config block */
}
else /* here to pre-process a key */
{
Skein_assert(sizeof(cfg.b) >= sizeof(ctx->X));
/* do a mini-Init right here */
ctx->h.hashBitLen=8*sizeof(ctx->X); /* set output hash bit count = state size */
Skein_Start_New_Type(ctx,KEY); /* set tweaks: T0 = 0; T1 = KEY type */
memset(ctx->X,0,sizeof(ctx->X)); /* zero the initial chaining variables */
Skein_512_Update(ctx,key,keyBytes); /* hash the key */
Skein_512_Final_Pad(ctx,cfg.b); /* put result into cfg.b[] */
memcpy(ctx->X,cfg.b,sizeof(cfg.b)); /* copy over into ctx->X[] */
#if SKEIN_NEED_SWAP
{
uint_t i;
for (i=0; i<SKEIN_512_STATE_WORDS; i++) /* convert key bytes to context words */
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);
memset(&cfg.w,0,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 */
cfg.w[2] = Skein_Swap64(treeInfo); /* tree hash config info (or SKEIN_CFG_TREE_INFO_SEQUENTIAL) */
Skein_Show_Key(512,&ctx->h,key,keyBytes);
/* compute the initial chaining values from config block */
Skein_512_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;
}
/* finalize the hash computation and output the result */
int Skein_512_Final(Skein_512_Ctxt_t *ctx, u08b_t *hashVal)
{
size_t i,n,byteCnt;
u64b_t X[SKEIN_512_STATE_WORDS];
Skein_Assert(ctx->h.bCnt <= SKEIN_512_BLOCK_BYTES,SKEIN_FAIL); /* catch uninitialized context */
ctx->h.T[1] |= SKEIN_T1_FLAG_FINAL; /* tag as the final block */
if (ctx->h.bCnt < SKEIN_512_BLOCK_BYTES) /* zero pad b[] if necessary */
memset(&ctx->b[ctx->h.bCnt],0,SKEIN_512_BLOCK_BYTES - ctx->h.bCnt);
Skein_512_Process_Block(ctx,ctx->b,1,ctx->h.bCnt); /* process the final block */
/* 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*SKEIN_512_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);
Skein_512_Process_Block(ctx,ctx->b,1,sizeof(u64b_t)); /* run "counter mode" */
n = byteCnt - i*SKEIN_512_BLOCK_BYTES; /* number of output bytes left to go */
if (n >= SKEIN_512_BLOCK_BYTES)
n = SKEIN_512_BLOCK_BYTES;
Skein_Put64_LSB_First(hashVal+i*SKEIN_512_BLOCK_BYTES,ctx->X,n); /* "output" the ctr mode bytes */
Skein_Show_Final(512,&ctx->h,n,hashVal+i*SKEIN_512_BLOCK_BYTES);
memcpy(ctx->X,X,sizeof(X)); /* restore the counter mode key for next time */
}
return SKEIN_SUCCESS;
}
/* init the context for a straight hashing operation */
int
Skein_512_Init(Skein_512_Ctxt_t *ctx, size_t hashBitLen)
{
union {
uint8_t b[SKEIN_512_STATE_BYTES];
uint64_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 */
#ifndef SKEIN_NO_PRECOMP
case 512:
bcopy(SKEIN_512_IV_512, ctx->X, sizeof (ctx->X));
break;
case 384:
bcopy(SKEIN_512_IV_384, ctx->X, sizeof (ctx->X));
break;
case 256:
bcopy(SKEIN_512_IV_256, ctx->X, sizeof (ctx->X));
break;
case 224:
bcopy(SKEIN_512_IV_224, ctx->X, sizeof (ctx->X));
break;
#endif
default:
/*
* here if there is no precomputed IV value available
* build/process the config block, type == CONFIG (could be
* precomputed)
*/
/* set tweaks: T0=0; T1=CFG | FINAL */
Skein_Start_New_Type(ctx, CFG_FINAL);
/* set the schema, version */
cfg.w[0] = Skein_Swap64(SKEIN_SCHEMA_VER);
/* hash result length in bits */
cfg.w[1] = Skein_Swap64(hashBitLen);
cfg.w[2] = Skein_Swap64(SKEIN_CFG_TREE_INFO_SEQUENTIAL);
/* zero pad config block */
bzero(&cfg.w[3], sizeof (cfg) - 3 * sizeof (cfg.w[0]));
/* compute the initial chaining values from config block */
/* zero the chaining variables */
bzero(ctx->X, sizeof (ctx->X));
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);
}
/* process data to be hashed */
int Skein::Update(const BitSequence *data, DataLength databitlen)
{
/* only the final Update() call is allowed do partial bytes, else assert an error */
Skein_Assert((skeinState.u.h.T[1] & SKEIN_T1_FLAG_BIT_PAD) == 0 || databitlen == 0, FAIL);
Skein_Assert(skeinState.statebits % 256 == 0 && (skeinState.statebits-256) < 1024,FAIL);
if ((databitlen & 7) == 0) /* partial bytes? */
{
switch ((skeinState.statebits >> 8) & 3)
{
case 2: return Skein_512_Update(&skeinState.u.ctx_512,data,databitlen >> 3);
case 1: return Skein_256_Update(&skeinState.u.ctx_256,data,databitlen >> 3);
case 0: return Skein1024_Update(&skeinState.u.ctx1024,data,databitlen >> 3);
default: return FAIL;
}
}
else
{ /* handle partial final byte */
int skeinCtxPrepare(SkeinCtx_t* ctx, SkeinSize_t size)
{
Skein_Assert(ctx && size, SKEIN_FAIL);
memset(ctx ,0, sizeof(SkeinCtx_t));
ctx->skeinSize = size;
return SKEIN_SUCCESS;
}
int skeinMacInit(SkeinCtx_t* ctx, const uint8_t *key, size_t keyLen,
size_t hashBitLen)
{
int ret = SKEIN_FAIL;
u64b_t* X = NULL;
size_t Xlen = 0;
uint64_t treeInfo = SKEIN_CFG_TREE_INFO_SEQUENTIAL;
Skein_Assert(ctx, SKEIN_FAIL);
X = ctx->m.s256.X;
Xlen = (size_t)(ctx->skeinSize/8);
Skein_Assert(hashBitLen, SKEIN_BAD_HASHLEN);
switch (ctx->skeinSize) {
case Skein256:
ret = Skein_256_InitExt(&ctx->m.s256, hashBitLen,
treeInfo,
(const u08b_t*)key, keyLen);
break;
case Skein512:
ret = Skein_512_InitExt(&ctx->m.s512, hashBitLen,
treeInfo,
(const u08b_t*)key, keyLen);
break;
case Skein1024:
ret = Skein1024_InitExt(&ctx->m.s1024, hashBitLen,
treeInfo,
(const u08b_t*)key, keyLen);
break;
}
if (ret == SKEIN_SUCCESS) {
/* Save chaining variables for this combination of key, keyLen, hashBitLen */
memcpy(ctx->XSave, X, Xlen);
}
return ret;
}
int Skein_512_Final_Pad(Skein_512_Ctxt_t *ctx, u08b_t *hashVal)
{
Skein_Assert(ctx->h.bCnt <= SKEIN_512_BLOCK_BYTES,SKEIN_FAIL); /* catch uninitialized context */
ctx->h.T[1] |= SKEIN_T1_FLAG_FINAL; /* tag as the final block */
if (ctx->h.bCnt < SKEIN_512_BLOCK_BYTES) /* zero pad b[] if necessary */
memset(&ctx->b[ctx->h.bCnt],0,SKEIN_512_BLOCK_BYTES - ctx->h.bCnt);
Skein_512_Process_Block(ctx,ctx->b,1,ctx->h.bCnt); /* process the final block */
Skein_Put64_LSB_First(hashVal,ctx->X,SKEIN_512_BLOCK_BYTES); /* "output" the state bytes */
return SKEIN_SUCCESS;
}
/* process the input bytes */
int
Skein1024_Update(Skein1024_Ctxt_t *ctx, const uint8_t *msg, size_t msgByteCnt)
{
size_t n;
/* catch uninitialized context */
Skein_Assert(ctx->h.bCnt <= SKEIN1024_BLOCK_BYTES, SKEIN_FAIL);
/* process full blocks, if any */
if (msgByteCnt + ctx->h.bCnt > SKEIN1024_BLOCK_BYTES) {
/* finish up any buffered message data */
if (ctx->h.bCnt) {
/* # bytes free in buffer b[] */
n = SKEIN1024_BLOCK_BYTES - ctx->h.bCnt;
if (n) {
/* check on our logic here */
Skein_assert(n < msgByteCnt);
bcopy(msg, &ctx->b[ctx->h.bCnt], n);
msgByteCnt -= n;
msg += n;
ctx->h.bCnt += n;
}
Skein_assert(ctx->h.bCnt == SKEIN1024_BLOCK_BYTES);
Skein1024_Process_Block(ctx, ctx->b, 1,
SKEIN1024_BLOCK_BYTES);
ctx->h.bCnt = 0;
}
/*
* now process any remaining full blocks, directly from
* input message data
*/
if (msgByteCnt > SKEIN1024_BLOCK_BYTES) {
/* number of full blocks to process */
n = (msgByteCnt - 1) / SKEIN1024_BLOCK_BYTES;
Skein1024_Process_Block(ctx, msg, n,
SKEIN1024_BLOCK_BYTES);
msgByteCnt -= n * SKEIN1024_BLOCK_BYTES;
msg += n * SKEIN1024_BLOCK_BYTES;
}
Skein_assert(ctx->h.bCnt == 0);
}
/* copy any remaining source message data bytes into b[] */
if (msgByteCnt) {
Skein_assert(msgByteCnt + ctx->h.bCnt <= SKEIN1024_BLOCK_BYTES);
bcopy(msg, &ctx->b[ctx->h.bCnt], msgByteCnt);
ctx->h.bCnt += msgByteCnt;
}
return (SKEIN_SUCCESS);
}
/* init the context for a straight hashing operation */
int Skein_256_Init(Skein_256_Ctxt_t *ctx, size_t hashBitLen)
{
union
{
u08b_t b[SKEIN_256_STATE_BYTES];
u64b_t w[SKEIN_256_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 256:
memcpy(ctx->X,SKEIN_256_IV_256,sizeof(ctx->X));
break;
case 224:
memcpy(ctx->X,SKEIN_256_IV_224,sizeof(ctx->X));
break;
case 160:
memcpy(ctx->X,SKEIN_256_IV_160,sizeof(ctx->X));
break;
case 128:
memcpy(ctx->X,SKEIN_256_IV_128,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_256_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;
}
int skeinFinal(SkeinCtx_t* ctx, uint8_t* hash)
{
int ret = SKEIN_FAIL;
Skein_Assert(ctx, SKEIN_FAIL);
switch (ctx->skeinSize) {
case Skein256:
ret = Skein_256_Final(&ctx->m.s256, (u08b_t*)hash);
break;
case Skein512:
ret = Skein_512_Final(&ctx->m.s512, (u08b_t*)hash);
break;
case Skein1024:
ret = Skein1024_Final(&ctx->m.s1024, (u08b_t*)hash);
break;
}
return ret;
}
/* finalize the hash computation and output the block, no OUTPUT stage */
int
Skein_256_Final_Pad(Skein_256_Ctxt_t *ctx, uint8_t *hashVal)
{
/* catch uninitialized context */
Skein_Assert(ctx->h.bCnt <= SKEIN_256_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 < SKEIN_256_BLOCK_BYTES)
bzero(&ctx->b[ctx->h.bCnt],
SKEIN_256_BLOCK_BYTES - ctx->h.bCnt);
/* process the final block */
Skein_256_Process_Block(ctx, ctx->b, 1, ctx->h.bCnt);
/* "output" the state bytes */
Skein_Put64_LSB_First(hashVal, ctx->X, SKEIN_256_BLOCK_BYTES);
return (SKEIN_SUCCESS);
}
int skeinUpdate(SkeinCtx_t *ctx, const uint8_t *msg,
size_t msgByteCnt)
{
int ret = SKEIN_FAIL;
Skein_Assert(ctx, SKEIN_FAIL);
switch (ctx->skeinSize) {
case Skein256:
ret = Skein_256_Update(&ctx->m.s256, (const u08b_t*)msg, msgByteCnt);
break;
case Skein512:
ret = Skein_512_Update(&ctx->m.s512, (const u08b_t*)msg, msgByteCnt);
break;
case Skein1024:
ret = Skein1024_Update(&ctx->m.s1024, (const u08b_t*)msg, msgByteCnt);
break;
}
return ret;
}
/* select the context size and init the context */
int Skein::Init(int hashbitlen)
{
#if SKEIN_256_NIST_MAX_HASH_BITS
if (hashbitlen <= SKEIN_256_NIST_MAX_HASHBITS)
{
Skein_Assert(hashbitlen > 0,BAD_HASHLEN);
skeinState.statebits = 64*SKEIN_256_STATE_WORDS;
return Skein_256_Init(&skeinState.u.ctx_256,(size_t) hashbitlen);
}
#endif
if (hashbitlen <= SKEIN_512_NIST_MAX_HASHBITS)
{
skeinState.statebits = 64*SKEIN_512_STATE_WORDS;
return Skein_512_Init(&skeinState.u.ctx_512,(size_t) hashbitlen);
}
else
{
skeinState.statebits = 64*SKEIN1024_STATE_WORDS;
return Skein1024_Init(&skeinState.u.ctx1024,(size_t) hashbitlen);
}
}
int skeinInit(SkeinCtx_t* ctx, size_t hashBitLen)
{
int ret = SKEIN_FAIL;
size_t Xlen = 0;
u64b_t* X = NULL;
uint64_t treeInfo = SKEIN_CFG_TREE_INFO_SEQUENTIAL;
Skein_Assert(ctx, SKEIN_FAIL);
/*
* The following two lines rely of the fact that the real Skein contexts are
* a union in out context and thus have tha maximum memory available.
* The beauty of C :-) .
*/
X = ctx->m.s256.X;
Xlen = (size_t)(ctx->skeinSize/8);
/*
* If size is the same and hash bit length is zero then reuse
* the save chaining variables.
*/
switch (ctx->skeinSize) {
case Skein256:
ret = Skein_256_InitExt(&ctx->m.s256, hashBitLen,
treeInfo, NULL, 0);
break;
case Skein512:
ret = Skein_512_InitExt(&ctx->m.s512, hashBitLen,
treeInfo, NULL, 0);
break;
case Skein1024:
ret = Skein1024_InitExt(&ctx->m.s1024, hashBitLen,
treeInfo, NULL, 0);
break;
}
if (ret == SKEIN_SUCCESS) {
/* Save chaining variables for this combination of size and hashBitLen */
memcpy(ctx->XSave, X, Xlen);
}
return ret;
}
int skeinUpdateBits(SkeinCtx_t *ctx, const uint8_t *msg,
size_t msgBitCnt)
{
/*
* I've used the bit pad implementation from skein_test.c (see NIST CD)
* and modified it to use the convenience functions and added some pointer
* arithmetic.
*/
size_t length;
uint8_t mask;
uint8_t* up;
/* only the final Update() call is allowed do partial bytes, else assert an error */
Skein_Assert((ctx->m.h.T[1] & SKEIN_T1_FLAG_BIT_PAD) == 0 || msgBitCnt == 0, SKEIN_FAIL);
/* if number of bits is a multiple of bytes - that's easy */
if ((msgBitCnt & 0x7) == 0) {
return skeinUpdate(ctx, msg, msgBitCnt >> 3);
}
skeinUpdate(ctx, msg, (msgBitCnt >> 3) + 1);
/*
* The next line rely on the fact that the real Skein contexts
* are a union in our context. After the addition the pointer points to
* Skein's real partial block buffer.
* If this layout ever changes we have to adapt this as well.
*/
up = (uint8_t*)ctx->m.s256.X + ctx->skeinSize / 8;
Skein_Set_Bit_Pad_Flag(ctx->m.h); /* set tweak flag for the skeinFinal call */
/* now "pad" the final partial byte the way NIST likes */
length = ctx->m.h.bCnt; /* get the bCnt value (same location for all block sizes) */
Skein_assert(length != 0); /* internal sanity check: there IS a partial byte in the buffer! */
mask = (uint8_t) (1u << (7 - (msgBitCnt & 7))); /* partial byte bit mask */
up[length-1] = (uint8_t)((up[length-1] & (0-mask))|mask); /* apply bit padding on final byte (in the buffer) */
return SKEIN_SUCCESS;
}
/* just do the OUTPUT stage */
int
Skein1024_Output(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);
/* 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(256, &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);
}
