/* pwdbased.c

 *

 * Copyright (C) 2006-2023 wolfSSL Inc.

 *

 * This file is part of wolfSSL.

 *

 * wolfSSL is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * wolfSSL is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA

 */

#ifdef HAVE_CONFIG_H

    #include <config.h>

#endif

#include <wolfssl/wolfcrypt/settings.h>

#ifndef NO_PWDBASED

#include <wolfssl/wolfcrypt/pwdbased.h>

#include <wolfssl/wolfcrypt/hmac.h>

#include <wolfssl/wolfcrypt/hash.h>

#include <wolfssl/wolfcrypt/wolfmath.h>

#include <wolfssl/wolfcrypt/error-crypt.h>

#ifdef NO_INLINE

    #include <wolfssl/wolfcrypt/misc.h>

#else

    #define WOLFSSL_MISC_INCLUDED

    #include <wolfcrypt/src/misc.c>

#endif

#ifdef HAVE_PBKDF1

/* PKCS#5 v1.5 with non standard extension to optionally derive the extra data (IV) */

int wc_PBKDF1_ex(byte* key, int keyLen, byte* iv, int ivLen,

    const byte* passwd, int passwdLen, const byte* salt, int saltLen,

    int iterations, int hashType, void* heap)

{

    int  err;

    int  keyLeft, ivLeft, i;

    int  store;

    int  keyOutput = 0;

    int  digestLen;

    byte digest[WC_MAX_DIGEST_SIZE];

#ifdef WOLFSSL_SMALL_STACK

    wc_HashAlg* hash = NULL;

#else

    wc_HashAlg  hash[1];

#endif

    enum wc_HashType hashT;

    (void)heap;

    if (key == NULL || keyLen < 0 || passwdLen < 0 || saltLen < 0 || ivLen < 0){

        return BAD_FUNC_ARG;

    }

    if (iterations <= 0)

        iterations = 1;

    hashT = wc_HashTypeConvert(hashType);

    err = wc_HashGetDigestSize(hashT);

    if (err < 0)

        return err;

    digestLen = err;

    /* initialize hash */

#ifdef WOLFSSL_SMALL_STACK

    hash = (wc_HashAlg*)XMALLOC(sizeof(wc_HashAlg), heap,

                                DYNAMIC_TYPE_HASHCTX);

    if (hash == NULL)

        return MEMORY_E;

#endif

    err = wc_HashInit_ex(hash, hashT, heap, INVALID_DEVID);

    if (err != 0) {

    #ifdef WOLFSSL_SMALL_STACK

        XFREE(hash, heap, DYNAMIC_TYPE_HASHCTX);

    #endif

        return err;

    }

    keyLeft = keyLen;

    ivLeft  = ivLen;

    while (keyOutput < (keyLen + ivLen)) {

        int digestLeft = digestLen;

        /* D_(i - 1) */

        if (keyOutput) { /* first time D_0 is empty */

            err = wc_HashUpdate(hash, hashT, digest, (word32)digestLen);

            if (err != 0) break;

        }

        /* data */

        err = wc_HashUpdate(hash, hashT, passwd, (word32)passwdLen);

        if (err != 0) break;

        /* salt */

        if (salt) {

            err = wc_HashUpdate(hash, hashT, salt, (word32)saltLen);

            if (err != 0) break;

        }

        err = wc_HashFinal(hash, hashT, digest);

        if (err != 0) break;

        /* count */

        for (i = 1; i < iterations; i++) {

            err = wc_HashUpdate(hash, hashT, digest, (word32)digestLen);

            if (err != 0) break;

            err = wc_HashFinal(hash, hashT, digest);

            if (err != 0) break;

        }

        if (err != 0) break;

        if (keyLeft) {

            store = (int)min((word32)keyLeft, (word32)digestLen);

            XMEMCPY(&key[keyLen - keyLeft], digest, (size_t)store);

            keyOutput  += store;

            keyLeft    -= store;

            digestLeft -= store;

        }

        if (ivLeft && digestLeft) {

            store = (int)min((word32)ivLeft, (word32)digestLeft);

            if (iv != NULL)

                XMEMCPY(&iv[ivLen - ivLeft],

                        &digest[digestLen - digestLeft], (size_t)store);

            keyOutput += store;

            ivLeft    -= store;

        }

    }

    wc_HashFree(hash, hashT);

#ifdef WOLFSSL_SMALL_STACK

    XFREE(hash, heap, DYNAMIC_TYPE_HASHCTX);

#endif

    if (err != 0)

        return err;

    if (keyOutput != (keyLen + ivLen))

        return BUFFER_E;

    return err;

}

/* PKCS#5 v1.5 */

int wc_PBKDF1(byte* output, const byte* passwd, int pLen, const byte* salt,

           int sLen, int iterations, int kLen, int hashType)

{

    return wc_PBKDF1_ex(output, kLen, NULL, 0,

        passwd, pLen, salt, sLen, iterations, hashType, NULL);

}

#endif /* HAVE_PKCS5 */

#if defined(HAVE_PBKDF2) && !defined(NO_HMAC)

int wc_PBKDF2_ex(byte* output, const byte* passwd, int pLen, const byte* salt,

           int sLen, int iterations, int kLen, int hashType, void* heap, int devId)

{

    int    hLen;

    int    ret;

#ifdef WOLFSSL_SMALL_STACK

    byte*  buffer;

    Hmac*  hmac;

#else

    byte   buffer[WC_MAX_DIGEST_SIZE];

    Hmac   hmac[1];

#endif

    enum wc_HashType hashT;

    if (output == NULL || pLen < 0 || sLen < 0 || kLen < 0) {

        return BAD_FUNC_ARG;

    }

    if (iterations <= 0)

        iterations = 1;

    hashT = wc_HashTypeConvert(hashType);

    hLen = wc_HashGetDigestSize(hashT);

    if (hLen < 0)

        return BAD_FUNC_ARG;

#ifdef WOLFSSL_SMALL_STACK

    buffer = (byte*)XMALLOC(WC_MAX_DIGEST_SIZE, heap, DYNAMIC_TYPE_TMP_BUFFER);

    if (buffer == NULL)

        return MEMORY_E;

    hmac = (Hmac*)XMALLOC(sizeof(Hmac), heap, DYNAMIC_TYPE_HMAC);

    if (hmac == NULL) {

        XFREE(buffer, heap, DYNAMIC_TYPE_TMP_BUFFER);

        return MEMORY_E;

    }

#endif

    ret = wc_HmacInit(hmac, heap, devId);

    if (ret == 0) {

        word32 i = 1;

        /* use int hashType here, since HMAC FIPS uses the old unique value */

        ret = wc_HmacSetKey(hmac, hashType, passwd, (word32)pLen);

        while (ret == 0 && kLen) {

            int currentLen;

            int j;

            ret = wc_HmacUpdate(hmac, salt, (word32)sLen);

            if (ret != 0)

                break;

            /* encode i */

            for (j = 0; j < 4; j++) {

                byte b = (byte)(i >> ((3-j) * 8));

                ret = wc_HmacUpdate(hmac, &b, 1);

                if (ret != 0)

                    break;

            }

            /* check ret from inside for loop */

            if (ret != 0)

                break;

            ret = wc_HmacFinal(hmac, buffer);

            if (ret != 0)

                break;

            currentLen = (int)min((word32)kLen, (word32)hLen);

            XMEMCPY(output, buffer, (size_t)currentLen);

            for (j = 1; j < iterations; j++) {

                ret = wc_HmacUpdate(hmac, buffer, (word32)hLen);

                if (ret != 0)

                    break;

                ret = wc_HmacFinal(hmac, buffer);

                if (ret != 0)

                    break;

                xorbuf(output, buffer, (word32)currentLen);

            }

            /* check ret from inside for loop */

            if (ret != 0)

                break;

            output += currentLen;

            kLen   -= currentLen;

            i++;

        }

        wc_HmacFree(hmac);

    }

#ifdef WOLFSSL_SMALL_STACK

    XFREE(buffer, heap, DYNAMIC_TYPE_TMP_BUFFER);

    XFREE(hmac, heap, DYNAMIC_TYPE_HMAC);

#endif

    return ret;

}

int wc_PBKDF2(byte* output, const byte* passwd, int pLen, const byte* salt,

           int sLen, int iterations, int kLen, int hashType)

{

    return wc_PBKDF2_ex(output, passwd, pLen, salt, sLen, iterations, kLen,

        hashType, NULL, INVALID_DEVID);

}

#endif /* HAVE_PBKDF2 && !NO_HMAC */

#ifdef HAVE_PKCS12

/* helper for PKCS12_PBKDF(), does hash operation */

static int DoPKCS12Hash(int hashType, byte* buffer, word32 totalLen,

                 byte* Ai, word32 u, int iterations)

{

    int i;

    int ret = 0;

#ifdef WOLFSSL_SMALL_STACK

    wc_HashAlg* hash = NULL;

#else

    wc_HashAlg  hash[1];

#endif

    enum wc_HashType hashT;

    if (buffer == NULL || Ai == NULL) {

        return BAD_FUNC_ARG;

    }

    hashT = wc_HashTypeConvert(hashType);

    /* initialize hash */

#ifdef WOLFSSL_SMALL_STACK

    hash = (wc_HashAlg*)XMALLOC(sizeof(wc_HashAlg), NULL,

                                DYNAMIC_TYPE_HASHCTX);

    if (hash == NULL)

        return MEMORY_E;

#endif

    ret = wc_HashInit(hash, hashT);

    if (ret != 0) {

    #ifdef WOLFSSL_SMALL_STACK

        XFREE(hash, NULL, DYNAMIC_TYPE_HASHCTX);

    #endif

        return ret;

    }

    ret = wc_HashUpdate(hash, hashT, buffer, totalLen);

    if (ret == 0)

        ret = wc_HashFinal(hash, hashT, Ai);

    for (i = 1; i < iterations; i++) {

        if (ret == 0)

            ret = wc_HashUpdate(hash, hashT, Ai, u);

        if (ret == 0)

            ret = wc_HashFinal(hash, hashT, Ai);

    }

    wc_HashFree(hash, hashT);

#ifdef WOLFSSL_SMALL_STACK

    XFREE(hash, NULL, DYNAMIC_TYPE_HASHCTX);

#endif

    return ret;

}

int wc_PKCS12_PBKDF(byte* output, const byte* passwd, int passLen,

    const byte* salt, int saltLen, int iterations, int kLen, int hashType,

    int id)

{

    return wc_PKCS12_PBKDF_ex(output, passwd, passLen, salt, saltLen,

                              iterations, kLen, hashType, id, NULL);

}

/* extended API that allows a heap hint to be used */

int wc_PKCS12_PBKDF_ex(byte* output, const byte* passwd, int passLen,

                       const byte* salt, int saltLen, int iterations, int kLen,

                       int hashType, int id, void* heap)

{

    /* all in bytes instead of bits */

    word32 u, v, dLen, pLen, iLen, sLen, totalLen;

    int    dynamic = 0;

    int    ret = 0;

    word32 i;

    byte   *D, *S, *P, *I;

#ifdef WOLFSSL_SMALL_STACK

    byte   staticBuffer[1]; /* force dynamic usage */

#else

    byte   staticBuffer[1024];

#endif

    byte*  buffer = staticBuffer;

#ifdef WOLFSSL_SMALL_STACK

    byte*  Ai = NULL;

    byte*  B = NULL;

    mp_int *B1 = NULL;

    mp_int *i1 = NULL;

    mp_int *res = NULL;

#else

    byte   Ai[WC_MAX_DIGEST_SIZE];

    byte   B[WC_MAX_BLOCK_SIZE];

    mp_int B1[1];

    mp_int i1[1];

    mp_int res[1];

#endif

    enum wc_HashType hashT;

    (void)heap;

    if (output == NULL || passLen <= 0 || saltLen <= 0 || kLen < 0) {

        return BAD_FUNC_ARG;

    }

    if (iterations <= 0)

        iterations = 1;

    hashT = wc_HashTypeConvert(hashType);

    ret = wc_HashGetDigestSize(hashT);

    if (ret < 0)

        return ret;

    if (ret == 0)

        return BAD_STATE_E;

    u = (word32)ret;

    ret = wc_HashGetBlockSize(hashT);

    if (ret < 0)

        return ret;

    if (ret == 0)

        return BAD_STATE_E;

    v = (word32)ret;

#ifdef WOLFSSL_SMALL_STACK

    Ai = (byte*)XMALLOC(WC_MAX_DIGEST_SIZE, heap, DYNAMIC_TYPE_TMP_BUFFER);

    if (Ai == NULL)

        return MEMORY_E;

    B = (byte*)XMALLOC(WC_MAX_BLOCK_SIZE, heap, DYNAMIC_TYPE_TMP_BUFFER);

    if (B == NULL) {

        XFREE(Ai, heap, DYNAMIC_TYPE_TMP_BUFFER);

        return MEMORY_E;

    }

#endif

    XMEMSET(Ai, 0, WC_MAX_DIGEST_SIZE);

    XMEMSET(B,  0, WC_MAX_BLOCK_SIZE);

    dLen = v;

    sLen = v * (((word32)saltLen + v - 1) / v);

    /* with passLen checked at the top of the function for >= 0 then passLen

     * must be 1 or greater here and is always 'true' */

    pLen = v * (((word32)passLen + v - 1) / v);

    iLen = sLen + pLen;

    totalLen = dLen + sLen + pLen;

    if (totalLen > sizeof(staticBuffer)) {

        buffer = (byte*)XMALLOC(totalLen, heap, DYNAMIC_TYPE_KEY);

        if (buffer == NULL) {

#ifdef WOLFSSL_SMALL_STACK

            XFREE(Ai, heap, DYNAMIC_TYPE_TMP_BUFFER);

            XFREE(B,  heap, DYNAMIC_TYPE_TMP_BUFFER);

#endif

            return MEMORY_E;

        }

        dynamic = 1;

    }

    D = buffer;

    S = D + dLen;

    P = S + sLen;

    I = S;

    XMEMSET(D, id, dLen);

    for (i = 0; i < sLen; i++)

        S[i] = salt[i % (word32)saltLen];

    for (i = 0; i < pLen; i++)

        P[i] = passwd[i % (word32)passLen];

#ifdef WOLFSSL_SMALL_STACK

    if (((B1 = (mp_int *)XMALLOC(sizeof(*B1), heap, DYNAMIC_TYPE_TMP_BUFFER))

         == NULL) ||

        ((i1 = (mp_int *)XMALLOC(sizeof(*i1), heap, DYNAMIC_TYPE_TMP_BUFFER))

         == NULL) ||

        ((res = (mp_int *)XMALLOC(sizeof(*res), heap, DYNAMIC_TYPE_TMP_BUFFER))

         == NULL)) {

        ret = MEMORY_E;

        goto out;

    }

#endif

    while (kLen > 0) {

        word32 currentLen;

        ret = DoPKCS12Hash(hashType, buffer, totalLen, Ai, u, iterations);

        if (ret < 0)

            break;

        for (i = 0; i < v; i++)

            B[i] = Ai[(word32)i % u];

        if (mp_init(B1) != MP_OKAY)

            ret = MP_INIT_E;

        else if (mp_read_unsigned_bin(B1, B, v) != MP_OKAY)

            ret = MP_READ_E;

        else if (mp_add_d(B1, (mp_digit)1, B1) != MP_OKAY)

            ret = MP_ADD_E;

        if (ret != 0) {

            mp_clear(B1);

            break;

        }

        for (i = 0; i < iLen; i += v) {

            int    outSz;

            if (mp_init_multi(i1, res, NULL, NULL, NULL, NULL) != MP_OKAY) {

                ret = MP_INIT_E;

                break;

            }

            if (mp_read_unsigned_bin(i1, I + i, v) != MP_OKAY)

                ret = MP_READ_E;

            else if (mp_add(i1, B1, res) != MP_OKAY)

                ret = MP_ADD_E;

            else if ( (outSz = mp_unsigned_bin_size(res)) < 0)

                ret = MP_TO_E;

            else {

                if (outSz > (int)v) {

                    /* take off MSB */

                    byte  tmp[WC_MAX_BLOCK_SIZE + 1];

                    ret = mp_to_unsigned_bin(res, tmp);

                    XMEMCPY(I + i, tmp + 1, v);

                }

                else if (outSz < (int)v) {

                    XMEMSET(I + i, 0, v - (word32)outSz);

                    ret = mp_to_unsigned_bin(res, I + i + v - (word32)outSz);

                }

                else

                    ret = mp_to_unsigned_bin(res, I + i);

            }

            mp_clear(i1);

            mp_clear(res);

            if (ret < 0) break;

        }

        if (ret < 0) {

            mp_clear(B1);

            break;

        }

        currentLen = min((word32)kLen, u);

        XMEMCPY(output, Ai, currentLen);

        output += currentLen;

        kLen   -= (int)currentLen;

        mp_clear(B1);

    }

#ifdef WOLFSSL_SMALL_STACK

  out:

    if (Ai != NULL)

        XFREE(Ai, heap, DYNAMIC_TYPE_TMP_BUFFER);

    if (B != NULL)

        XFREE(B,  heap, DYNAMIC_TYPE_TMP_BUFFER);

    if (B1 != NULL)

        XFREE(B1, heap, DYNAMIC_TYPE_TMP_BUFFER);

    if (i1 != NULL)

        XFREE(i1, heap, DYNAMIC_TYPE_TMP_BUFFER);

    if (res != NULL)

        XFREE(res, heap, DYNAMIC_TYPE_TMP_BUFFER);

#endif

    if (dynamic)

        XFREE(buffer, heap, DYNAMIC_TYPE_KEY);

    return ret;

}

#endif /* HAVE_PKCS12 */

#ifdef HAVE_SCRYPT

#ifdef NO_HMAC

   #error scrypt requires HMAC

#endif

/* Rotate the 32-bit value a by b bits to the left.

 *

 * a  32-bit value.

 * b  Number of bits to rotate.

 * returns rotated value.

 */

#define R(a, b) rotlFixed(a, b)

/* (2^32 - 1) */

#define SCRYPT_WORD32_MAX 4294967295U

/* One round of Salsa20/8.

 * Code taken from RFC 7914: scrypt PBKDF.

 *

 * out  Output buffer.

 * in   Input data to hash.

 */

static void scryptSalsa(word32* out, word32* in)

{

    int    i;

    word32 x[16];

#ifdef LITTLE_ENDIAN_ORDER

    XMEMCPY(x, in, sizeof(x));

#else

    for (i = 0; i < 16; i++)

        x[i] = ByteReverseWord32(in[i]);

#endif

    for (i = 8; i > 0; i -= 2) {

        x[ 4] ^= R(x[ 0] + x[12],  7);  x[ 8] ^= R(x[ 4] + x[ 0],  9);

        x[12] ^= R(x[ 8] + x[ 4], 13);  x[ 0] ^= R(x[12] + x[ 8], 18);

        x[ 9] ^= R(x[ 5] + x[ 1],  7);  x[13] ^= R(x[ 9] + x[ 5],  9);

        x[ 1] ^= R(x[13] + x[ 9], 13);  x[ 5] ^= R(x[ 1] + x[13], 18);

        x[14] ^= R(x[10] + x[ 6],  7);  x[ 2] ^= R(x[14] + x[10],  9);

        x[ 6] ^= R(x[ 2] + x[14], 13);  x[10] ^= R(x[ 6] + x[ 2], 18);

        x[ 3] ^= R(x[15] + x[11],  7);  x[ 7] ^= R(x[ 3] + x[15],  9);

        x[11] ^= R(x[ 7] + x[ 3], 13);  x[15] ^= R(x[11] + x[ 7], 18);

        x[ 1] ^= R(x[ 0] + x[ 3],  7);  x[ 2] ^= R(x[ 1] + x[ 0],  9);

        x[ 3] ^= R(x[ 2] + x[ 1], 13);  x[ 0] ^= R(x[ 3] + x[ 2], 18);

        x[ 6] ^= R(x[ 5] + x[ 4],  7);  x[ 7] ^= R(x[ 6] + x[ 5],  9);

        x[ 4] ^= R(x[ 7] + x[ 6], 13);  x[ 5] ^= R(x[ 4] + x[ 7], 18);

        x[11] ^= R(x[10] + x[ 9],  7);  x[ 8] ^= R(x[11] + x[10],  9);

        x[ 9] ^= R(x[ 8] + x[11], 13);  x[10] ^= R(x[ 9] + x[ 8], 18);

        x[12] ^= R(x[15] + x[14],  7);  x[13] ^= R(x[12] + x[15],  9);

        x[14] ^= R(x[13] + x[12], 13);  x[15] ^= R(x[14] + x[13], 18);

    }

#ifdef LITTLE_ENDIAN_ORDER

    for (i = 0; i < 16; ++i)

        out[i] = in[i] + x[i];

#else

    for (i = 0; i < 16; i++)

        out[i] = ByteReverseWord32(ByteReverseWord32(in[i]) + x[i]);

#endif

}

/* Mix a block using Salsa20/8.

 * Based on RFC 7914: scrypt PBKDF.

 *

 * b  Blocks to mix.

 * y  Temporary storage.

 * r  Size of the block.

 */

static void scryptBlockMix(byte* b, byte* y, int r)

{

#ifdef WORD64_AVAILABLE

    word64  x[8];

    word64* b64 = (word64*)b;

    word64* y64 = (word64*)y;

#else

    word32  x[16];

    word32* b32 = (word32*)b;

    word32* y32 = (word32*)y;

#endif

    int  i;

    int  j;

    /* Step 1. */

    XMEMCPY(x, b + (2 * r - 1) * 64, sizeof(x));

    /* Step 2. */

    for (i = 0; i < 2 * r; i++)

    {

#ifdef WORD64_AVAILABLE

        for (j = 0; j < 8; j++)

            x[j] ^= b64[i * 8 + j];

#else

        for (j = 0; j < 16; j++)

            x[j] ^= b32[i * 16 + j];

#endif

        scryptSalsa((word32*)x, (word32*)x);

        XMEMCPY(y + i * 64, x, sizeof(x));

    }

    /* Step 3. */

    for (i = 0; i < r; i++) {

#ifdef WORD64_AVAILABLE

        for (j = 0; j < 8; j++) {

            b64[i * 8 + j] = y64[2 * i * 8 + j];

            b64[(r + i) * 8 + j] = y64[(2 * i + 1) * 8 + j];

        }

#else

        for (j = 0; j < 16; j++) {

            b32[i * 16 + j] = y32[2 * i * 16 + j];

            b32[(r + i) * 16 + j] = y32[(2 * i + 1) * 16 + j];

        }

#endif

    }

}

/* Random oracles mix.

 * Based on RFC 7914: scrypt PBKDF.

 *

 * x  Data to mix.

 * v  Temporary buffer.

 * y  Temporary buffer for the block mix.

 * r  Block size parameter.

 * n  CPU/Memory cost parameter.

 */

static void scryptROMix(byte* x, byte* v, byte* y, int r, word32 n)

{

    word32 i;

    word32 j;

    word32 k;

    word32 bSz = (word32)(128 * r);

#ifdef WORD64_AVAILABLE

    word64* x64 = (word64*)x;

    word64* v64 = (word64*)v;

#else

    word32* x32 = (word32*)x;

    word32* v32 = (word32*)v;

#endif

    /* Step 1. X = B (B not needed therefore not implemented) */

    /* Step 2. */

    for (i = 0; i < n; i++)

    {

        XMEMCPY(v + i * bSz, x, bSz);

        scryptBlockMix(x, y, r);

    }

    /* Step 3. */

    for (i = 0; i < n; i++)

    {

#ifdef LITTLE_ENDIAN_ORDER

#ifdef WORD64_AVAILABLE

        j = (word32)(*(word64*)(x + (2*r - 1) * 64) & (n-1));

#else

        j = *(word32*)(x + (2*r - 1) * 64) & (n-1);

#endif

#else

        byte* t = x + (2*r - 1) * 64;

        j = (t[0] | (t[1] << 8) | (t[2] << 16) | ((word32)t[3] << 24)) & (n-1);

#endif

#ifdef WORD64_AVAILABLE

        for (k = 0; k < bSz / 8; k++)

            x64[k] ^= v64[j * bSz / 8 + k];

#else

        for (k = 0; k < bSz / 4; k++)

            x32[k] ^= v32[j * bSz / 4 + k];

#endif

        scryptBlockMix(x, y, r);

    }

    /* Step 4. B' = X (B = X = B' so not needed, therefore not implemented) */

}

/* Generates an key derived from a password and salt using a memory hard

 * algorithm.

 * Implements RFC 7914: scrypt PBKDF.

 *

 * output     The derived key.

 * passwd     The password to derive key from.

 * passLen    The length of the password.

 * salt       The key specific data.

 * saltLen    The length of the salt data.

 * cost       The CPU/memory cost parameter. Range: 1..(128*r/8-1)

 *            (Iterations = 2^cost)

 * blockSize  The number of 128 byte octets in a working block.

 * parallel   The number of parallel mix operations to perform.

 *            (Note: this implementation does not use threads.)

 * dkLen      The length of the derived key in bytes.

 * returns BAD_FUNC_ARG when: blockSize is too large for cost.

 */

int wc_scrypt(byte* output, const byte* passwd, int passLen,

              const byte* salt, int saltLen, int cost, int blockSize,

              int parallel, int dkLen)

{

    int    ret = 0;

    int    i;

    byte*  v = NULL;

    byte*  y = NULL;

    byte*  blocks = NULL;

    word32 blocksSz;

    word32 bSz;

    if (blockSize > 8)

        return BAD_FUNC_ARG;

    if (cost < 1 || cost >= 128 * blockSize / 8 || parallel < 1 || dkLen < 1)

        return BAD_FUNC_ARG;

    /* The following comparison used to be:

     *    ((word32)parallel > (SCRYPT_MAX / (128 * blockSize)))

     * where SCRYPT_MAX is (2^32 - 1) * 32. For some compilers, the RHS of

     * the comparison is greater than parallel's type. It wouldn't promote

     * both sides to word64. What follows is just arithmetic simplification.

     */

    if (parallel > (int)((SCRYPT_WORD32_MAX / 4) / (word32)blockSize))

        return BAD_FUNC_ARG;

    bSz = 128 * (word32)blockSize;

    if (parallel > (int)(SCRYPT_WORD32_MAX / bSz))

        return BAD_FUNC_ARG;

    blocksSz = bSz * (word32)parallel;

    blocks = (byte*)XMALLOC((size_t)blocksSz, NULL, DYNAMIC_TYPE_TMP_BUFFER);

    if (blocks == NULL) {

        ret = MEMORY_E;

        goto end;

    }

    /* Temporary for scryptROMix. */

    v = (byte*)XMALLOC((size_t)((1 << cost) * bSz), NULL,

                       DYNAMIC_TYPE_TMP_BUFFER);

    if (v == NULL) {

        ret = MEMORY_E;

        goto end;

    }

    /* Temporary for scryptBlockMix. */

    y = (byte*)XMALLOC((size_t)(blockSize * 128), NULL,

                       DYNAMIC_TYPE_TMP_BUFFER);

    if (y == NULL) {

        ret = MEMORY_E;

        goto end;

    }

    /* Step 1. */

    ret = wc_PBKDF2(blocks, passwd, passLen, salt, saltLen, 1, (int)blocksSz,

                    WC_SHA256);

    if (ret != 0)

        goto end;

    /* Step 2. */

    for (i = 0; i < parallel; i++)

        scryptROMix(blocks + i * (int)bSz, v, y, (int)blockSize, 1 << cost);

    /* Step 3. */

    ret = wc_PBKDF2(output, passwd, passLen, blocks, (int)blocksSz, 1, dkLen,

                    WC_SHA256);

end:

    if (blocks != NULL)

        XFREE(blocks, NULL, DYNAMIC_TYPE_TMP_BUFFER);

    if (v != NULL)

        XFREE(v, NULL, DYNAMIC_TYPE_TMP_BUFFER);

    if (y != NULL)

        XFREE(y, NULL, DYNAMIC_TYPE_TMP_BUFFER);

    return ret;

}

/* Generates an key derived from a password and salt using a memory hard

 * algorithm.

 * Implements RFC 7914: scrypt PBKDF.

 *

 * output      Derived key.

 * passwd      Password to derive key from.

 * passLen     Length of the password.

 * salt        Key specific data.

 * saltLen     Length of the salt data.

 * iterations  Number of iterations to perform. Range: 1 << (1..(128*r/8-1))

 * blockSize   Number of 128 byte octets in a working block.

 * parallel    Number of parallel mix operations to perform.

 *             (Note: this implementation does not use threads.)

 * dkLen       Length of the derived key in bytes.

 * returns BAD_FUNC_ARG when: iterations is not a power of 2 or blockSize is too

 *                            large for iterations.

 */

int wc_scrypt_ex(byte* output, const byte* passwd, int passLen,

                 const byte* salt, int saltLen, word32 iterations,

                 int blockSize, int parallel, int dkLen)

{

    int cost;

    /* Iterations must be a power of 2. */

    if ((iterations & (iterations - 1)) != 0)

        return BAD_FUNC_ARG;

    for (cost = -1; iterations != 0; cost++) {

        iterations >>= 1;

    }

    return wc_scrypt(output, passwd, passLen, salt, saltLen, cost, blockSize,

                     parallel, dkLen);

}

#endif /* HAVE_SCRYPT */

#endif /* NO_PWDBASED */