int PEM_ASN1_write_bio(i2d_of_void *i2d, const char *name, BIO *bp,
                       void *x, const EVP_CIPHER *enc, unsigned char *kstr,
                       int klen, pem_password_cb *callback, void *u)
{
    EVP_CIPHER_CTX *ctx = NULL;
    int dsize = 0, i = 0, j = 0, ret = 0;
    unsigned char *p, *data = NULL;
    const char *objstr = NULL;
    char buf[PEM_BUFSIZE];
    unsigned char key[EVP_MAX_KEY_LENGTH];
    unsigned char iv[EVP_MAX_IV_LENGTH];

    if (enc != NULL) {
        objstr = OBJ_nid2sn(EVP_CIPHER_nid(enc));
        if (objstr == NULL || EVP_CIPHER_iv_length(enc) == 0
                || EVP_CIPHER_iv_length(enc) > (int)sizeof(iv)
                   /*
                    * Check "Proc-Type: 4,Encrypted\nDEK-Info: objstr,hex-iv\n"
                    * fits into buf
                    */
                || (strlen(objstr) + 23 + 2 * EVP_CIPHER_iv_length(enc) + 13)
                   > sizeof(buf)) {
            PEMerr(PEM_F_PEM_ASN1_WRITE_BIO, PEM_R_UNSUPPORTED_CIPHER);
            goto err;
        }
    }

    if ((dsize = i2d(x, NULL)) < 0) {
        PEMerr(PEM_F_PEM_ASN1_WRITE_BIO, ERR_R_ASN1_LIB);
        dsize = 0;
        goto err;
    }
    /* dsize + 8 bytes are needed */
    /* actually it needs the cipher block size extra... */
    data = OPENSSL_malloc((unsigned int)dsize + 20);
    if (data == NULL) {
        PEMerr(PEM_F_PEM_ASN1_WRITE_BIO, ERR_R_MALLOC_FAILURE);
        goto err;
    }
    p = data;
    i = i2d(x, &p);

    if (enc != NULL) {
        if (kstr == NULL) {
            if (callback == NULL)
                klen = PEM_def_callback(buf, PEM_BUFSIZE, 1, u);
            else
                klen = (*callback) (buf, PEM_BUFSIZE, 1, u);
            if (klen <= 0) {
                PEMerr(PEM_F_PEM_ASN1_WRITE_BIO, PEM_R_READ_KEY);
                goto err;
            }
#ifdef CHARSET_EBCDIC
            /* Convert the pass phrase from EBCDIC */
            ebcdic2ascii(buf, buf, klen);
#endif
            kstr = (unsigned char *)buf;
        }
        if (RAND_bytes(iv, EVP_CIPHER_iv_length(enc)) <= 0) /* Generate a salt */
            goto err;
        /*
         * The 'iv' is used as the iv and as a salt.  It is NOT taken from
         * the BytesToKey function
         */
        if (!EVP_BytesToKey(enc, EVP_md5(), iv, kstr, klen, 1, key, NULL))
            goto err;

        if (kstr == (unsigned char *)buf)
            OPENSSL_cleanse(buf, PEM_BUFSIZE);

        buf[0] = '\0';
        PEM_proc_type(buf, PEM_TYPE_ENCRYPTED);
        PEM_dek_info(buf, objstr, EVP_CIPHER_iv_length(enc), (char *)iv);
        /* k=strlen(buf); */

        ret = 1;
        if ((ctx = EVP_CIPHER_CTX_new()) == NULL
            || !EVP_EncryptInit_ex(ctx, enc, NULL, key, iv)
            || !EVP_EncryptUpdate(ctx, data, &j, data, i)
            || !EVP_EncryptFinal_ex(ctx, &(data[j]), &i))
            ret = 0;
        if (ret == 0)
            goto err;
        i += j;
    } else {
        ret = 1;
        buf[0] = '\0';
    }
    i = PEM_write_bio(bp, name, buf, data, i);
    if (i <= 0)
        ret = 0;
 err:
    OPENSSL_cleanse(key, sizeof(key));
    OPENSSL_cleanse(iv, sizeof(iv));
    EVP_CIPHER_CTX_free(ctx);
    OPENSSL_cleanse(buf, PEM_BUFSIZE);
    OPENSSL_clear_free(data, (unsigned int)dsize);
    return ret;
}