text: /* ed448.c
   *
   * Copyright (C) 2006-2021 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
   */
  
  /* Implemented to: RFC 8032 */
  
  /* Based On Daniel J Bernstein's ed25519 Public Domain ref10 work.
   * Reworked for curve448 by Sean Parkinson.
   */
  
  #ifdef HAVE_CONFIG_H
      #include <config.h>
  #endif
  
  /* in case user set HAVE_ED448 there */
  #include <wolfssl/wolfcrypt/settings.h>
  
  #ifdef HAVE_ED448
  
  #include <wolfssl/wolfcrypt/ed448.h>
  #include <wolfssl/wolfcrypt/error-crypt.h>
  #include <wolfssl/wolfcrypt/hash.h>
  #ifdef NO_INLINE
      #include <wolfssl/wolfcrypt/misc.h>
  #else
      #define WOLFSSL_MISC_INCLUDED
      #include <wolfcrypt/src/misc.c>
  #endif
  
  #if defined(HAVE_ED448_SIGN) || defined(HAVE_ED448_VERIFY)
  /* Size of context bytes to use with hash when signing and verifying. */
  #define ED448CTX_SIZE    8
  /* Context to pass to hash when signing and verifying. */
  static const byte ed448Ctx[ED448CTX_SIZE+1] = "SigEd448";
  #endif
  
  
  static int ed448_hash_init(ed448_key* key, wc_Shake *sha)
  {
      int ret;
  
      ret = wc_InitShake256(sha, key->heap,
  #if defined(WOLF_CRYPTO_CB)
                             key->devId
  #else
                             INVALID_DEVID
  #endif
          );
  
  #ifdef WOLFSSL_ED448_PERSISTENT_SHA
      if (ret == 0)
          key->sha_clean_flag = 1;
  #endif
  
      return ret;
  }
  
  #ifdef WOLFSSL_ED448_PERSISTENT_SHA
  static int ed448_hash_reset(ed448_key* key)
  {
      int ret;
  
      if (key->sha_clean_flag)
          ret = 0;
      else {
          wc_Shake256_Free(&key->sha);
          ret = wc_InitShake256(&key->sha, key->heap,
  #if defined(WOLF_CRYPTO_CB)
                                key->devId
  #else
                                INVALID_DEVID
  #endif
              );
          if (ret == 0)
              key->sha_clean_flag = 1;
      }
      return ret;
  }
  #endif /* WOLFSSL_ED448_PERSISTENT_SHA */
  
  static int ed448_hash_update(ed448_key* key, wc_Shake *sha, const byte* data,
                               word32 len)
  {
  #ifdef WOLFSSL_ED448_PERSISTENT_SHA
      if (key->sha_clean_flag)
          key->sha_clean_flag = 0;
  #else
      (void)key;
  #endif
      return wc_Shake256_Update(sha, data, len);
  }
  
  static int ed448_hash_final(ed448_key* key, wc_Shake *sha, byte* hash,
                              word32 hashLen)
  {
      int ret = wc_Shake256_Final(sha, hash, hashLen);
  #ifdef WOLFSSL_ED448_PERSISTENT_SHA
      if (ret == 0)
          key->sha_clean_flag = 1;
  #else
      (void)key;
  #endif
      return ret;
  }
  
  static void ed448_hash_free(ed448_key* key, wc_Shake *sha)
  {
      wc_Shake256_Free(sha);
  #ifdef WOLFSSL_ED448_PERSISTENT_SHA
      key->sha_clean_flag = 0;
  #else
      (void)key;
  #endif
  }
  
  
  static int ed448_hash(ed448_key* key, const byte* in, word32 inLen,
                        byte* hash, word32 hashLen)
  {
      int ret;
  #ifndef WOLFSSL_ED448_PERSISTENT_SHA
      wc_Shake sha[1];
  #else
      wc_Shake *sha;
  #endif
  
      if (key == NULL || (in == NULL && inLen > 0) || hash == NULL) {
          return BAD_FUNC_ARG;
      }
  
  #ifdef WOLFSSL_ED448_PERSISTENT_SHA
      sha = &key->sha;
      ret = ed448_hash_reset(key);
  #else
      ret = ed448_hash_init(key, sha);
  #endif
      if (ret < 0)
          return ret;
  
      ret = ed448_hash_update(key, sha, in, inLen);
      if (ret == 0)
          ret = ed448_hash_final(key, sha, hash, hashLen);
  
  #ifndef WOLFSSL_ED448_PERSISTENT_SHA
      ed448_hash_free(key, sha);
  #endif
  
      return ret;
  }
  
  /* Derive the public key for the private key.
   *
   * key       [in]  Ed448 key object.
   * pubKey    [in]  Byte array to hold te public key.
   * pubKeySz  [in]  Size of the array in bytes.
   * returns BAD_FUNC_ARG when key is NULL or pubKeySz is not equal to
   *         ED448_PUB_KEY_SIZE,
   *         other -ve value on hash failure,
   *         0 otherwise.
   */
  int wc_ed448_make_public(ed448_key* key, unsigned char* pubKey, word32 pubKeySz)
  {
      int   ret = 0;
      byte  az[ED448_PRV_KEY_SIZE];
      ge448_p2 A;
  
      if ((key == NULL) || (pubKey == NULL) || (pubKeySz != ED448_PUB_KEY_SIZE)) {
          ret = BAD_FUNC_ARG;
      }
  
      if (ret == 0)
          ret = ed448_hash(key, key->k, ED448_KEY_SIZE, az, sizeof(az));
  
      if (ret == 0) {
          /* apply clamp */
          az[0]  &= 0xfc;
          az[55] |= 0x80;
          az[56]  = 0x00;
  
          ge448_scalarmult_base(&A, az);
          ge448_to_bytes(pubKey, &A);
      }
  
      return ret;
  }
  
  /* Make a new ed448 private/public key.
   *
   * rng      [in]  Random number generator.
   * keysize  [in]  Size of the key to generate.
   * key      [in]  Ed448 key object.
   * returns BAD_FUNC_ARG when rng or key is NULL or keySz is not equal to
   *         ED448_KEY_SIZE,
   *         other -ve value on random number or hash failure,
   *         0 otherwise.
   */
  int wc_ed448_make_key(WC_RNG* rng, int keySz, ed448_key* key)
  {
      int ret = 0;
  
      if ((rng == NULL) || (key == NULL)) {
          ret = BAD_FUNC_ARG;
      }
  
      /* ed448 has 57 byte key sizes */
      if ((ret == 0) && (keySz != ED448_KEY_SIZE)) {
          ret = BAD_FUNC_ARG;
      }
  
      if (ret == 0) {
          ret = wc_RNG_GenerateBlock(rng, key->k, ED448_KEY_SIZE);
      }
      if (ret == 0) {
          ret = wc_ed448_make_public(key, key->p, ED448_PUB_KEY_SIZE);
          if (ret != 0) {
              ForceZero(key->k, ED448_KEY_SIZE);
          }
      }
      if (ret == 0) {
          /* put public key after private key, on the same buffer */
          XMEMMOVE(key->k + ED448_KEY_SIZE, key->p, ED448_PUB_KEY_SIZE);
  
          key->pubKeySet = 1;
      }
  
      return ret;
  }
  
  #ifdef HAVE_ED448_SIGN
  /* Sign the message using the ed448 private key.
   *
   *  in          [in]      Message to sign.
   *  inLen       [in]      Length of the message in bytes.
   *  out         [in]      Buffer to write signature into.
   *  outLen      [in/out]  On in, size of buffer.
   *                        On out, the length of the signature in bytes.
   *  key         [in]      Ed448 key to use when signing
   *  type        [in]      Type of signature to perform: Ed448 or Ed448ph
   *  context     [in]      Context of signing.
   *  contextLen  [in]      Length of context in bytes.
   *  returns BAD_FUNC_ARG when a parameter is NULL or contextLen is zero when and
   *          context is not NULL or public key not set,
   *          BUFFER_E when outLen is less than ED448_SIG_SIZE,
   *          other -ve values when hash fails,
   *          0 otherwise.
   */
  int wc_ed448_sign_msg_ex(const byte* in, word32 inLen, byte* out,
                            word32 *outLen, ed448_key* key, byte type,
                            const byte* context, byte contextLen)
  {
      ge448_p2 R;
      byte     nonce[ED448_SIG_SIZE];
      byte     hram[ED448_SIG_SIZE];
      byte     az[ED448_PRV_KEY_SIZE];
      int      ret = 0;
  
      /* sanity check on arguments */
      if ((in == NULL) || (out == NULL) || (outLen == NULL) || (key == NULL) ||
                                       ((context == NULL) && (contextLen != 0))) {
          ret = BAD_FUNC_ARG;
      }
      if ((ret == 0) && (!key->pubKeySet)) {
          ret = BAD_FUNC_ARG;
      }
  
      /* check and set up out length */
      if ((ret == 0) && (*outLen < ED448_SIG_SIZE)) {
          *outLen = ED448_SIG_SIZE;
          ret = BUFFER_E;
      }
  
      if (ret == 0) {
          *outLen = ED448_SIG_SIZE;
  
          /* step 1: create nonce to use where nonce is r in
             r = H(h_b, ... ,h_2b-1,M) */
          ret = ed448_hash(key, key->k, ED448_KEY_SIZE, az, sizeof(az));
      }
      if (ret == 0) {
  #ifdef WOLFSSL_ED448_PERSISTENT_SHA
          wc_Shake *sha = &key->sha;
  #else
          wc_Shake sha[1];
          ret = ed448_hash_init(key, sha);
          if (ret < 0)
              return ret;
  #endif
          /* apply clamp */
          az[0]  &= 0xfc;
          az[55] |= 0x80;
          az[56]  = 0x00;
  
          ret = ed448_hash_update(key, sha, ed448Ctx, ED448CTX_SIZE);
  
          if (ret == 0) {
              ret = ed448_hash_update(key, sha, &type, sizeof(type));
          }
          if (ret == 0) {
              ret = ed448_hash_update(key, sha, &contextLen, sizeof(contextLen));
          }
          if ((ret == 0) && (context != NULL)) {
              ret = ed448_hash_update(key, sha, context, contextLen);
          }
          if (ret == 0) {
              ret = ed448_hash_update(key, sha, az + ED448_KEY_SIZE, ED448_KEY_SIZE);
          }
          if (ret == 0) {
              ret = ed448_hash_update(key, sha, in, inLen);
          }
          if (ret == 0) {
              ret = ed448_hash_final(key, sha, nonce, sizeof(nonce));
          }
  #ifndef WOLFSSL_ED448_PERSISTENT_SHA
          ed448_hash_free(key, sha);
  #endif
      }
      if (ret == 0) {
  #ifdef WOLFSSL_ED448_PERSISTENT_SHA
          wc_Shake *sha = &key->sha;
  #else
          wc_Shake sha[1];
          ret = ed448_hash_init(key, sha);
          if (ret < 0)
              return ret;
  #endif
          sc448_reduce(nonce);
  
          /* step 2: computing R = rB where rB is the scalar multiplication of
             r and B */
          ge448_scalarmult_base(&R,nonce);
          ge448_to_bytes(out,&R);
  
          /* step 3: hash R + public key + message getting H(R,A,M) then
             creating S = (r + H(R,A,M)a) mod l */
  
          ret = ed448_hash_update(key, sha, ed448Ctx, ED448CTX_SIZE);
          if (ret == 0) {
              ret = ed448_hash_update(key, sha, &type, sizeof(type));
          }
          if (ret == 0) {
              ret = ed448_hash_update(key, sha, &contextLen, sizeof(contextLen));
          }
          if ((ret == 0) && (context != NULL)) {
              ret = ed448_hash_update(key, sha, context, contextLen);
          }
          if (ret == 0) {
              ret = ed448_hash_update(key, sha, out, ED448_SIG_SIZE/2);
          }
          if (ret == 0) {
              ret = ed448_hash_update(key, sha, key->p, ED448_PUB_KEY_SIZE);
          }
          if (ret == 0) {
              ret = ed448_hash_update(key, sha, in, inLen);
          }
          if (ret == 0) {
              ret = ed448_hash_final(key, sha, hram, sizeof(hram));
          }
  #ifndef WOLFSSL_ED448_PERSISTENT_SHA
          ed448_hash_free(key, sha);
  #endif
      }
  
      if (ret == 0) {
          sc448_reduce(hram);
          sc448_muladd(out + (ED448_SIG_SIZE/2), hram, az, nonce);
      }
  
      return ret;
  }
  
  /* Sign the message using the ed448 private key.
   * Signature type is Ed448.
   *
   *  in          [in]      Message to sign.
   *  inLen       [in]      Length of the message in bytes.
   *  out         [in]      Buffer to write signature into.
   *  outLen      [in/out]  On in, size of buffer.
   *                        On out, the length of the signature in bytes.
   *  key         [in]      Ed448 key to use when signing
   *  context     [in]      Context of signing.
   *  contextLen  [in]      Length of context in bytes.
   *  returns BAD_FUNC_ARG when a parameter is NULL or contextLen is zero when and
   *          context is not NULL or public key not set,
   *          BUFFER_E when outLen is less than ED448_SIG_SIZE,
   *          other -ve values when hash fails,
   *          0 otherwise.
   */
  int wc_ed448_sign_msg(const byte* in, word32 inLen, byte* out, word32 *outLen,
                        ed448_key* key, const byte* context, byte contextLen)
  {
      return wc_ed448_sign_msg_ex(in, inLen, out, outLen, key, Ed448, context,
                                                                      contextLen);
  }
  
  /* Sign the hash using the ed448 private key.
   * Signature type is Ed448ph.
   *
   *  hash        [in]      Hash of message to sign.
   *  hashLen     [in]      Length of hash of message in bytes.
   *  out         [in]      Buffer to write signature into.
   *  outLen      [in/out]  On in, size of buffer.
   *                        On out, the length of the signature in bytes.
   *  key         [in]      Ed448 key to use when signing
   *  context     [in]      Context of signing.
   *  contextLen  [in]      Length of context in bytes.
   *  returns BAD_FUNC_ARG when a parameter is NULL or contextLen is zero when and
   *          context is not NULL or public key not set,
   *          BUFFER_E when outLen is less than ED448_SIG_SIZE,
   *          other -ve values when hash fails,
   *          0 otherwise.
   */
  int wc_ed448ph_sign_hash(const byte* hash, word32 hashLen, byte* out,
                           word32 *outLen, ed448_key* key,
                           const byte* context, byte contextLen)
  {
      return wc_ed448_sign_msg_ex(hash, hashLen, out, outLen, key, Ed448ph,
                                  context, contextLen);
  }
  
  /* Sign the message using the ed448 private key.
   * Signature type is Ed448ph.
   *
   *  in          [in]      Message to sign.
   *  inLen       [in]      Length of the message to sign in bytes.
   *  out         [in]      Buffer to write signature into.
   *  outLen      [in/out]  On in, size of buffer.
   *                        On out, the length of the signature in bytes.
   *  key         [in]      Ed448 key to use when signing
   *  context     [in]      Context of signing.
   *  contextLen  [in]      Length of context in bytes.
   *  returns BAD_FUNC_ARG when a parameter is NULL or contextLen is zero when and
   *          context is not NULL or public key not set,
   *          BUFFER_E when outLen is less than ED448_SIG_SIZE,
   *          other -ve values when hash fails,
   *          0 otherwise.
   */
  int wc_ed448ph_sign_msg(const byte* in, word32 inLen, byte* out, word32 *outLen,
                          ed448_key* key, const byte* context, byte contextLen)
  {
      int  ret;
      byte hash[ED448_PREHASH_SIZE];
  
      ret = ed448_hash(key, in, inLen, hash, sizeof(hash));
  
      if (ret == 0) {
          ret = wc_ed448ph_sign_hash(hash, sizeof(hash), out, outLen, key,
                                                             context, contextLen);
      }
  
      return ret;
  }
  #endif /* HAVE_ED448_SIGN */
  
  #ifdef HAVE_ED448_VERIFY
  
  /* Verify the message using the ed448 public key.
   *
   *  sig         [in]  Signature to verify.
   *  sigLen      [in]  Size of signature in bytes.
   *  key         [in]  Ed448 key to use to verify.
   *  type        [in]  Type of signature to verify: Ed448 or Ed448ph
   *  context     [in]  Context of verification.
   *  contextLen  [in]  Length of context in bytes.
   *  returns BAD_FUNC_ARG when a parameter is NULL or contextLen is zero when and
   *          context is not NULL or public key not set,
   *          BUFFER_E when sigLen is less than ED448_SIG_SIZE,
   *          other -ve values when hash fails,
   *          0 otherwise.
   */
  
  static int ed448_verify_msg_init_with_sha(const byte* sig, word32 sigLen,
                                        ed448_key* key, wc_Shake *sha, byte type,
                                        const byte* context, byte contextLen)
  {
      int ret;
  
      /* sanity check on arguments */
      if ((sig == NULL) || (key == NULL) ||
          ((context == NULL) && (contextLen != 0))) {
          return BAD_FUNC_ARG;
      }
  
      /* check on basics needed to verify signature */
      if (sigLen != ED448_SIG_SIZE) {
          return BAD_FUNC_ARG;
      }
  
      /* find H(R,A,M) and store it as h */
  #ifdef WOLFSSL_ED448_PERSISTENT_SHA
      ret = ed448_hash_reset(key);
      if (ret < 0)
          return ret;
  #endif
  
      ret = ed448_hash_update(key, sha, ed448Ctx, ED448CTX_SIZE);
      if (ret == 0) {
          ret = ed448_hash_update(key, sha, &type, sizeof(type));
      }
      if (ret == 0) {
          ret = ed448_hash_update(key, sha, &contextLen, sizeof(contextLen));
      }
      if ((ret == 0) && (context != NULL)) {
          ret = ed448_hash_update(key, sha, context, contextLen);
      }
      if (ret == 0) {
          ret = ed448_hash_update(key, sha, sig, ED448_SIG_SIZE/2);
      }
      if (ret == 0) {
          ret = ed448_hash_update(key, sha, key->p, ED448_PUB_KEY_SIZE);
      }
  
      return ret;
  }
  
  /*
     msgSegment     an array of bytes containing a message segment
     msgSegmentLen  length of msgSegment
     key            Ed448 public key
     return         0 on success
  */
  static int ed448_verify_msg_update_with_sha(const byte* msgSegment,
                                          word32 msgSegmentLen,
                                          ed448_key* key,
                                          wc_Shake *sha)
  {
      /* sanity check on arguments */
      if (msgSegment == NULL || key == NULL)
          return BAD_FUNC_ARG;
  
      return ed448_hash_update(key, sha, msgSegment, msgSegmentLen);
  }
  
  /* Verify the message using the ed448 public key.
   *
   *  sig         [in]  Signature to verify.
   *  sigLen      [in]  Size of signature in bytes.
   *  res         [out] *res is set to 1 on successful verification.
   *  key         [in]  Ed448 key to use to verify.
   *  returns BAD_FUNC_ARG when a parameter is NULL or public key not set,
   *          BUFFER_E when sigLen is less than ED448_SIG_SIZE,
   *          other -ve values when hash fails,
   *          0 otherwise.
   */
  static int ed448_verify_msg_final_with_sha(const byte* sig, word32 sigLen,
                                       int* res, ed448_key* key, wc_Shake *sha)
  {
      byte     rcheck[ED448_KEY_SIZE];
      byte     h[ED448_SIG_SIZE];
      ge448_p2 A;
      ge448_p2 R;
      int      ret;
  
      /* sanity check on arguments */
      if ((sig == NULL) || (res == NULL) || (key == NULL))
          return BAD_FUNC_ARG;
  
      /* set verification failed by default */
      *res = 0;
  
      /* check on basics needed to verify signature */
      if (sigLen != ED448_SIG_SIZE)
          return BAD_FUNC_ARG;
  
      /* uncompress A (public key), test if valid, and negate it */
      if (ge448_from_bytes_negate_vartime(&A, key->p) != 0)
          return BAD_FUNC_ARG;
  
      ret = ed448_hash_final(key, sha, h, sizeof(h));
      if (ret != 0)
          return ret;
  
      sc448_reduce(h);
  
      /* Uses a fast single-signature verification SB = R + H(R,A,M)A becomes
       * SB - H(R,A,M)A saving decompression of R
       */
      ret = ge448_double_scalarmult_vartime(&R, h, &A,
                                            sig + (ED448_SIG_SIZE/2));
      if (ret != 0)
          return ret;
  
      ge448_to_bytes(rcheck, &R);
  
      /* comparison of R created to R in sig */
      if (ConstantCompare(rcheck, sig, ED448_SIG_SIZE/2) != 0) {
          ret = SIG_VERIFY_E;
      }
      else {
          /* set the verification status */
          *res = 1;
      }
  
      return ret;
  }
  
  #ifdef WOLFSSL_ED448_STREAMING_VERIFY
  int wc_ed448_verify_msg_init(const byte* sig, word32 sigLen, ed448_key* key,
                          byte type, const byte* context, byte contextLen)
  {
      return ed448_verify_msg_init_with_sha(sig, sigLen, key, &key->sha, type,
                                        context, contextLen);
  }
  
  int wc_ed448_verify_msg_update(const byte* msgSegment, word32 msgSegmentLen,
                               ed448_key* key)
  {
      return ed448_verify_msg_update_with_sha(msgSegment, msgSegmentLen, key,
                                          &key->sha);
  }
  
  int wc_ed448_verify_msg_final(const byte* sig, word32 sigLen,
                                int* res, ed448_key* key)
  {
      return ed448_verify_msg_final_with_sha(sig, sigLen, res, key, &key->sha);
  }
  #endif
  
  /* Verify the message using the ed448 public key.
   *
   *  sig         [in]  Signature to verify.
   *  sigLen      [in]  Size of signature in bytes.
   *  msg         [in]  Message to verify.
   *  msgLen      [in]  Length of the message in bytes.
   *  res         [out] *res is set to 1 on successful verification.
   *  key         [in]  Ed448 key to use to verify.
   *  type        [in]  Type of signature to verify: Ed448 or Ed448ph
   *  context     [in]  Context of verification.
   *  contextLen  [in]  Length of context in bytes.
   *  returns BAD_FUNC_ARG when a parameter is NULL or contextLen is zero when and
   *          context is not NULL or public key not set,
   *          BUFFER_E when sigLen is less than ED448_SIG_SIZE,
   *          other -ve values when hash fails,
   *          0 otherwise.
   */
  int wc_ed448_verify_msg_ex(const byte* sig, word32 sigLen, const byte* msg,
                              word32 msgLen, int* res, ed448_key* key,
                              byte type, const byte* context, byte contextLen)
  {
      int ret;
  #ifdef WOLFSSL_ED448_PERSISTENT_SHA
      wc_Shake *sha;
  #else
      wc_Shake sha[1];
  #endif
  
      if (key == NULL)
          return BAD_FUNC_ARG;
  
  #ifdef WOLFSSL_ED448_PERSISTENT_SHA
      sha = &key->sha;
  #else
      ret = ed448_hash_init(key, sha);
      if (ret < 0)
          return ret;
  #endif
  
      ret = ed448_verify_msg_init_with_sha(sig, sigLen, key, sha,
                                     type, context, contextLen);
      if (ret == 0)
          ret = ed448_verify_msg_update_with_sha(msg, msgLen, key, sha);
      if (ret == 0)
          ret = ed448_verify_msg_final_with_sha(sig, sigLen, res, key, sha);
  
  #ifndef WOLFSSL_ED448_PERSISTENT_SHA
      ed448_hash_free(key, sha);
  #endif
  
      return ret;
  }
  
  /* Verify the message using the ed448 public key.
   * Signature type is Ed448.
   *
   *  sig         [in]  Signature to verify.
   *  sigLen      [in]  Size of signature in bytes.
   *  msg         [in]  Message to verify.
   *  msgLen      [in]  Length of the message in bytes.
   *  key         [in]  Ed448 key to use to verify.
   *  context     [in]  Context of verification.
   *  contextLen  [in]  Length of context in bytes.
   *  returns BAD_FUNC_ARG when a parameter is NULL or contextLen is zero when and
   *          context is not NULL or public key not set,
   *          BUFFER_E when sigLen is less than ED448_SIG_SIZE,
   *          other -ve values when hash fails,
   *          0 otherwise.
   */
  int wc_ed448_verify_msg(const byte* sig, word32 sigLen, const byte* msg,
                          word32 msgLen, int* res, ed448_key* key,
                          const byte* context, byte contextLen)
  {
      return wc_ed448_verify_msg_ex(sig, sigLen, msg, msgLen, res, key, Ed448,
                                                             context, contextLen);
  }
  
  /* Verify the hash using the ed448 public key.
   * Signature type is Ed448ph.
   *
   *  sig         [in]  Signature to verify.
   *  sigLen      [in]  Size of signature in bytes.
   *  hash        [in]  Hash of message to verify.
   *  hashLen     [in]  Length of the hash in bytes.
   *  key         [in]  Ed448 key to use to verify.
   *  context     [in]  Context of verification.
   *  contextLen  [in]  Length of context in bytes.
   *  returns BAD_FUNC_ARG when a parameter is NULL or contextLen is zero when and
   *          context is not NULL or public key not set,
   *          BUFFER_E when sigLen is less than ED448_SIG_SIZE,
   *          other -ve values when hash fails,
   *          0 otherwise.
   */
  int wc_ed448ph_verify_hash(const byte* sig, word32 sigLen, const byte* hash,
                             word32 hashLen, int* res, ed448_key* key,
                             const byte* context, byte contextLen)
  {
      return wc_ed448_verify_msg_ex(sig, sigLen, hash, hashLen, res, key, Ed448ph,
                                                             context, contextLen);
  }
  
  /* Verify the message using the ed448 public key.
   * Signature type is Ed448ph.
   *
   *  sig         [in]  Signature to verify.
   *  sigLen      [in]  Size of signature in bytes.
   *  msg         [in]  Message to verify.
   *  msgLen      [in]  Length of the message in bytes.
   *  key         [in]  Ed448 key to use to verify.
   *  context     [in]  Context of verification.
   *  contextLen  [in]  Length of context in bytes.
   *  returns BAD_FUNC_ARG when a parameter is NULL or contextLen is zero when and
   *          context is not NULL or public key not set,
   *          BUFFER_E when sigLen is less than ED448_SIG_SIZE,
   *          other -ve values when hash fails,
   *          0 otherwise.
   */
  int wc_ed448ph_verify_msg(const byte* sig, word32 sigLen, const byte* msg,
                            word32 msgLen, int* res, ed448_key* key,
                            const byte* context, byte contextLen)
  {
      int  ret = 0;
      byte hash[ED448_PREHASH_SIZE];
  
      ret = ed448_hash(key, msg, msgLen, hash, sizeof(hash));
  
      if (ret == 0) {
          ret = wc_ed448ph_verify_hash(sig, sigLen, hash, sizeof(hash), res, key,
                                                             context, contextLen);
      }
  
      return ret;
  }
  #endif /* HAVE_ED448_VERIFY */
  
  /* Initialize the ed448 private/public key.
   *
   * key  [in]  Ed448 key.
   * heap [in]  heap pointer to pass to wc_InitShake256().
   * returns BAD_FUNC_ARG when key is NULL
   */
  int wc_ed448_init_ex(ed448_key* key, void *heap, int devId)
  {
      if (key == NULL)
          return BAD_FUNC_ARG;
  
      XMEMSET(key, 0, sizeof(ed448_key));
  
  #ifdef WOLF_CRYPTO_CB
      key->devId = devId;
  #else
      (void)devId;
  #endif
      key->heap = heap;
  
      fe448_init();
  
  #ifdef WOLFSSL_ED448_PERSISTENT_SHA
      return ed448_hash_init(key, &key->sha);
  #else /* !WOLFSSL_ED448_PERSISTENT_SHA */
      return 0;
  #endif /* WOLFSSL_ED448_PERSISTENT_SHA */
  }
  
  /* Initialize the ed448 private/public key.
   *
   * key  [in]  Ed448 key.
   * returns BAD_FUNC_ARG when key is NULL
   */
  int wc_ed448_init(ed448_key* key) {
      return wc_ed448_init_ex(key, NULL, INVALID_DEVID);
  }
  
  /* Clears the ed448 key data
   *
   * key  [in]  Ed448 key.
   */
  void wc_ed448_free(ed448_key* key)
  {
      if (key != NULL) {
  #ifdef WOLFSSL_ED448_PERSISTENT_SHA
          ed448_hash_free(key, &key->sha);
  #endif
          ForceZero(key, sizeof(ed448_key));
      }
  }
  
  
  #ifdef HAVE_ED448_KEY_EXPORT
  
  /* Export the ed448 public key.
   *
   * key     [in]      Ed448 public key.
   * out     [in]      Array to hold public key.
   * outLen  [in/out]  On in, the number of bytes in array.
   *                   On out, the number bytes put into array.
   * returns BAD_FUNC_ARG when a parameter is NULL,
   *         ECC_BAD_ARG_E when outLen is less than ED448_PUB_KEY_SIZE,
   *         0 otherwise.
   */
  int wc_ed448_export_public(ed448_key* key, byte* out, word32* outLen)
  {
      int ret = 0;
  
      /* sanity check on arguments */
      if ((key == NULL) || (out == NULL) || (outLen == NULL)) {
          ret = BAD_FUNC_ARG;
      }
  
      if ((ret == 0) && (*outLen < ED448_PUB_KEY_SIZE)) {
          *outLen = ED448_PUB_KEY_SIZE;
          ret = BUFFER_E;
      }
  
      if (ret == 0) {
          *outLen = ED448_PUB_KEY_SIZE;
          XMEMCPY(out, key->p, ED448_PUB_KEY_SIZE);
      }
  
      return ret;
  }
  
  #endif /* HAVE_ED448_KEY_EXPORT */
  
  
  #ifdef HAVE_ED448_KEY_IMPORT
  /* Import a compressed or uncompressed ed448 public key from a byte array.
   * Public key encoded in big-endian.
   *
   * in      [in]  Array holding public key.
   * inLen   [in]  Number of bytes of data in array.
   * key     [in]  Ed448 public key.
   * returns BAD_FUNC_ARG when a parameter is NULL or key format is not supported,
   *         0 otherwise.
   */
  int wc_ed448_import_public(const byte* in, word32 inLen, ed448_key* key)
  {
      int ret = 0;
  
      /* sanity check on arguments */
      if ((in == NULL) || (key == NULL)) {
          ret = BAD_FUNC_ARG;
      }
  
      if  (inLen < ED448_PUB_KEY_SIZE) {
          ret = BAD_FUNC_ARG;
      }
  
      if (ret == 0) {
          /* compressed prefix according to draft
           * https://tools.ietf.org/html/draft-ietf-openpgp-rfc4880bis-06 */
          if (in[0] == 0x40 && inLen > ED448_PUB_KEY_SIZE) {
              /* key is stored in compressed format so just copy in */
              XMEMCPY(key->p, (in + 1), ED448_PUB_KEY_SIZE);
              key->pubKeySet = 1;
          }
          /* importing uncompressed public key */
          else if (in[0] == 0x04 && inLen > 2*ED448_PUB_KEY_SIZE) {
              /* pass in (x,y) and store compressed key */
              ret = ge448_compress_key(key->p, in+1, in+1+ED448_PUB_KEY_SIZE);
              if (ret == 0)
                  key->pubKeySet = 1;
          }
          else if (inLen == ED448_PUB_KEY_SIZE) {
              /* if not specified compressed or uncompressed check key size
               * if key size is equal to compressed key size copy in key */
              XMEMCPY(key->p, in, ED448_PUB_KEY_SIZE);
              key->pubKeySet = 1;
          }
          else {
              /* bad public key format */
              ret = BAD_FUNC_ARG;
          }
      }
  
      return ret;
  }
  
  
  /* Import an ed448 private key from a byte array.
   *
   * priv    [in]  Array holding private key.
   * privSz  [in]  Number of bytes of data in array.
   * key     [in]  Ed448 private key.
   * returns BAD_FUNC_ARG when a parameter is NULL or privSz is less than
   *         ED448_KEY_SIZE,
   *         0 otherwise.
   */
  int wc_ed448_import_private_only(const byte* priv, word32 privSz,
                                   ed448_key* key)
  {
      int ret = 0;
  
      /* sanity check on arguments */
      if ((priv == NULL) || (key == NULL)) {
          ret = BAD_FUNC_ARG;
      }
  
      /* key size check */
      if ((ret == 0) && (privSz < ED448_KEY_SIZE)) {
          ret = BAD_FUNC_ARG;
      }
  
      if (ret == 0) {
          XMEMCPY(key->k, priv, ED448_KEY_SIZE);
      }
  
      return ret;
  }
  
  
  /* Import an ed448 private and public keys from byte array(s).
   *
   * priv    [in]  Array holding private key from wc_ed448_export_private_only(),
   *               or private+public keys from wc_ed448_export_private().
   * privSz  [in]  Number of bytes of data in private key array.
   * pub     [in]  Array holding public key (or NULL).
   * pubSz   [in]  Number of bytes of data in public key array (or 0).
   * key     [in]  Ed448 private/public key.
   * returns BAD_FUNC_ARG when a required parameter is NULL or an invalid
   *         combination of keys/lengths is supplied, 0 otherwise.
   */
  int wc_ed448_import_private_key(const byte* priv, word32 privSz,
                                  const byte* pub, word32 pubSz, ed448_key* key)
  {
      int ret;
  
      /* sanity check on arguments */
      if (priv == NULL || key == NULL)
          return BAD_FUNC_ARG;
  
      /* key size check */
      if (privSz < ED448_KEY_SIZE)
          return BAD_FUNC_ARG;
  
      if (pub == NULL) {
          if (pubSz != 0)
              return BAD_FUNC_ARG;
          if (privSz < ED448_PRV_KEY_SIZE)
              return BAD_FUNC_ARG;
          pub = priv + ED448_KEY_SIZE;
          pubSz = ED448_PUB_KEY_SIZE;
      } else if (pubSz < ED448_PUB_KEY_SIZE) {
          return BAD_FUNC_ARG;
      }
  
      /* import public key */
      ret = wc_ed448_import_public(pub, pubSz, key);
      if (ret != 0)
          return ret;
  
      /* make the private key (priv + pub) */
      XMEMCPY(key->k, priv, ED448_KEY_SIZE);
      XMEMCPY(key->k + ED448_KEY_SIZE, key->p, ED448_PUB_KEY_SIZE);
  
      return ret;
  }
  
  
  #endif /* HAVE_ED448_KEY_IMPORT */
  
  
  #ifdef HAVE_ED448_KEY_EXPORT
  
  /* Export the ed448 private key.
   *
   * key     [in]      Ed448 private key.
   * out     [in]      Array to hold private key.
   * outLen  [in/out]  On in, the number of bytes in array.
   *                   On out, the number bytes put into array.
   * returns BAD_FUNC_ARG when a parameter is NULL,
   *         ECC_BAD_ARG_E when outLen is less than ED448_KEY_SIZE,
   *         0 otherwise.
   */
  int wc_ed448_export_private_only(ed448_key* key, byte* out, word32* outLen)
  {
      int ret = 0;
  
      /* sanity checks on arguments */
      if ((key == NULL) || (out == NULL) || (outLen == NULL)) {
          ret = BAD_FUNC_ARG;
      }
  
      if ((ret == 0) && (*outLen < ED448_KEY_SIZE)) {
          *outLen = ED448_KEY_SIZE;
          ret = BUFFER_E;
      }
  
      if (ret == 0) {
          *outLen = ED448_KEY_SIZE;
          XMEMCPY(out, key->k, ED448_KEY_SIZE);
      }
  
      return ret;
  }
  
  /* Export the ed448 private and public key.
   *
   * key     [in]      Ed448 private/public key.
   * out     [in]      Array to hold private and public key.
   * outLen  [in/out]  On in, the number of bytes in array.
   *                   On out, the number bytes put into array.
   * returns BAD_FUNC_ARG when a parameter is NULL,
   *         BUFFER_E when outLen is less than ED448_PRV_KEY_SIZE,
   *         0 otherwise.
   */
  int wc_ed448_export_private(ed448_key* key, byte* out, word32* outLen)
  {
      int ret = 0;
  
      /* sanity checks on arguments */
      if ((key == NULL) || (out == NULL) || (outLen == NULL)) {
          ret = BAD_FUNC_ARG;
      }
  
      if ((ret == 0) && (*outLen < ED448_PRV_KEY_SIZE)) {
          *outLen = ED448_PRV_KEY_SIZE;
          ret = BUFFER_E;
      }
  
      if (ret == 0) {
          *outLen = ED448_PRV_KEY_SIZE;
          XMEMCPY(out, key->k, ED448_PRV_KEY_SIZE);
       }
  
      return ret;
  }
  
  /* Export the ed448 private and public key.
   *
   * key     [in]      Ed448 private/public key.
   * priv    [in]      Array to hold private key.
   * privSz  [in/out]  On in, the number of bytes in private key array.
   * pub     [in]      Array to hold  public key.
   * pubSz   [in/out]  On in, the number of bytes in public key array.
   *                   On out, the number bytes put into array.
   * returns BAD_FUNC_ARG when a parameter is NULL,
   *         BUFFER_E when privSz is less than ED448_PRV_KEY_SIZE or pubSz is less
   *         than ED448_PUB_KEY_SIZE,
   *         0 otherwise.
   */
  int wc_ed448_export_key(ed448_key* key, byte* priv, word32 *privSz,
                          byte* pub, word32 *pubSz)
  {
      int ret = 0;
  
      /* export 'full' private part */
      ret = wc_ed448_export_private(key, priv, privSz);
      if (ret == 0) {
          /* export public part */
          ret = wc_ed448_export_public(key, pub, pubSz);
      }
  
      return ret;
  }
  
  #endif /* HAVE_ED448_KEY_EXPORT */
  
  /* Check the public key of the ed448 key matches the private key.
   *
   * key     [in]      Ed448 private/public key.
   * returns BAD_FUNC_ARG when key is NULL,
   *         PUBLIC_KEY_E when the public key is not set or doesn't match,
   *         other -ve value on hash failure,
   *         0 otherwise.
   */
  int wc_ed448_check_key(ed448_key* key)
  {
      int ret = 0;
      unsigned char pubKey[ED448_PUB_KEY_SIZE];
  
      if (key == NULL) {
          ret = BAD_FUNC_ARG;
      }
  
      if (ret == 0 && !key->pubKeySet) {
          ret = PUBLIC_KEY_E;
      }
      if (ret == 0) {
          ret = wc_ed448_make_public(key, pubKey, sizeof(pubKey));
      }
      if ((ret == 0) && (XMEMCMP(pubKey, key->p, ED448_PUB_KEY_SIZE) != 0)) {
          ret = PUBLIC_KEY_E;
      }
  
      return ret;
  }
  
  /* Returns the size of an ed448 private key.
   *
   * key     [in]      Ed448 private/public key.
   * returns BAD_FUNC_ARG when key is NULL,
   *         ED448_KEY_SIZE otherwise.
   */
  int wc_ed448_size(ed448_key* key)
  {
      int ret = ED448_KEY_SIZE;
  
      if (key == NULL) {
          ret = BAD_FUNC_ARG;
      }
  
      return ret;
  }
  
  /* Returns the size of an ed448 private plus public key.
   *
   * key     [in]      Ed448 private/public key.
   * returns BAD_FUNC_ARG when key is NULL,
   *         ED448_PRV_KEY_SIZE otherwise.
   */
  int wc_ed448_priv_size(ed448_key* key)
  {
      int ret = ED448_PRV_KEY_SIZE;
  
      if (key == NULL) {
          ret = BAD_FUNC_ARG;
      }
  
      return ret;
  }
  
  /* Returns the size of an ed448 public key.
   *
   * key     [in]      Ed448 private/public key.
   * returns BAD_FUNC_ARG when key is NULL,
   *         ED448_PUB_KEY_SIZE otherwise.
   */
  int wc_ed448_pub_size(ed448_key* key)
  {
      int ret = ED448_PUB_KEY_SIZE;
  
      if (key == NULL) {
          ret = BAD_FUNC_ARG;
      }
  
      return ret;
  }
  
  /* Returns the size of an ed448 signature.
   *
   * key     [in]      Ed448 private/public key.
   * returns BAD_FUNC_ARG when key is NULL,
   *         ED448_SIG_SIZE otherwise.
   */
  int wc_ed448_sig_size(ed448_key* key)
  {
      int ret = ED448_SIG_SIZE;
  
      if (key == NULL) {
          ret = BAD_FUNC_ARG;
      }
  
      return ret;
  }
  
  #endif /* HAVE_ED448 */
  
  