while((bytes = fread (buffer, 1, 32, fp)) != 0)
{
    EVP_DecryptUpdate(e, buffer_out, &c_len, buffer, bytes);
    ret = fwrite(buffer_out, 1, c_len, fpout);
    printf("c_len %d bytes %d ret %dn", c_len, bytes, ret);
}

char *decrypt (char *key,
               char *iv,
               char *encryptedData,
               int encryptedLength)
{
    // Initialisation
    EVP_CIPHER_CTX *cryptCtx = EVP_CIPHER_CTX_new();
    EVP_CIPHER_CTX_init(cryptCtx);
    int decryptedLength = 0;
    int allocateSize = encryptedLength * sizeof(char);
    int lastDecryptLength = 0;
    char *decryptedData = (char *) malloc (allocateSize);
    memset(decryptedData, 0x00, allocateSize);
    int decryptResult = EVP_DecryptInit_ex(cryptCtx,
        EVP_bf_cbc(), NULL, key, iv);

    // EVP_DecryptInit_ex returns 1 if it succeeded.
    if (decryptResult == 1)
    {
        decryptResult = EVP_DecryptUpdate(cryptCtx, decryptedData,
            &decryptedLength, encryptedData, encryptedLength);

        // Note that EVP_DecryptUpdate will alter the value of the third parameter
        // to be equal to the amount of data that was written. This is not always the
        // entire length of the decrypted data! To finish the decryption process, use
        // EVP_DecryptFinal_ex. This will decrypt any remaining data.

        // Cleanup
        if (decryptResult == 1)
        {
            // Stick the final data at the end of the last
            // decrypted data.
            EVP_DecryptFinal_ex(cryptCtx,
                decryptedData + decryptedLength,
                &lastDecryptLength);
            decryptedLength = decryptedLength + lastDecryptLength;
            decryptedData[decryptedLength – 1] = ”;
            printf ("Decrypted size: %dn", decryptedLength);
            printf ("Decrypted data: n%snn", decryptedData);
        }
        else
        {
            printf ("EVP_DeccryptUpdate failure.n");
        }
    }
    else
    {
        printf ("EVP_DecryptInit_ex failure.n");
    }
    EVP_CIPHER_CTX_free(cryptCtx);
    EVP_cleanup();
    return decryptedData;
}