# Pastebin TqXyQhki
int verify_signature_hash(const unsigned char *data, int length_data, const unsigned char* signature, int length_signature, const char * public_key){
  unsigned char* base64_decoded_signature;
  size_t base64_decoded_signature_length;
  int authentic;
  int result = 0;
  
  EVP_PKEY *pkey;


  BIO* certbio = NULL;
  X509* cert = NULL;
  int ret;

  ERR_load_BIO_strings();
  ERR_load_crypto_strings();

  certbio = BIO_new(BIO_s_file());

  ret = BIO_read_filename(certbio, public_key);
  if (!(cert = PEM_read_bio_X509(certbio, NULL, 0, NULL))) {
    exit(-1);
  }

  if ((pkey = X509_get_pubkey(cert)) == NULL)
    printf("Error getting public key from certificate");

  if (pkey) {
    switch (pkey->type) {
      case EVP_PKEY_RSA:
        printf("%d bit RSA Key\n\n", EVP_PKEY_bits(pkey));
        break;
      case EVP_PKEY_DSA:
        printf("%d bit DSA Key\n\n", EVP_PKEY_bits(pkey));
        break;
      default:
        printf("%d bit non-RSA/DSA Key\n\n", EVP_PKEY_bits(pkey));
        break;
    }
  }
  
  base64_decoded_signature_length = base64Decode(signature, length_signature, &base64_decoded_signature);
  //openPublicRSAKey(pkey, public_key);
  EVP_MD_CTX* m_RSAVerifyCtx = EVP_MD_CTX_create();
  const EVP_MD *md = EVP_sha256();

  EVP_PKEY_CTX* pkey_ctx = EVP_PKEY_CTX_new(pkey, NULL); 

  
  
  if (1 != EVP_DigestVerifyInit(m_RSAVerifyCtx, pkey_ctx, md,NULL, pkey)) {
    handleErrors();
  }

  if (1 != EVP_PKEY_CTX_set_rsa_padding(m_RSAVerifyCtx->pctx, RSA_PKCS1_PADDING)){
    handleErrors();
  }
  
  if (1 != EVP_DigestVerifyUpdate(m_RSAVerifyCtx, data, length_data)) {
    handleErrors();
  } 

  if(1 != EVP_DigestVerifyFinal(m_RSAVerifyCtx, base64_decoded_signature, base64_decoded_signature_length)){
    handleErrors();
  }

  X509_free(cert);
  BIO_free_all(certbio);
  EVP_MD_CTX_destroy(m_RSAVerifyCtx);
  EVP_cleanup();

  return 1;
}