C++ Skein_Assert函数代码示例

/* [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;

}

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);
}