OSSL_ENCODER_TO_BIO(3ossl)

✨ OSSL_ENCODER_TO_BIO(3ossl) ✨

okay bestie, this is the OpenSSL manual page for OSSL_ENCODER_TO_BIO(3ossl), and it's literally all about the routines that perform an encoding. no cap, it's giving “make bytes go somewhere” energy 💅

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💖 NAME 💖

OSSL_ENCODER_to_data, OSSL_ENCODER_to_bio, OSSL_ENCODER_to_fp — routines to perform an encoding. periodt. 🎀

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🌸 SYNOPSIS 🌸

#include <openssl/encoder.h>

int OSSL_ENCODER_to_data(OSSL_ENCODER_CTX *ctx, unsigned char **pdata,
                         size_t *pdata_len);
int OSSL_ENCODER_to_bio(OSSL_ENCODER_CTX *ctx, BIO *out);
int OSSL_ENCODER_to_fp(OSSL_ENCODER_CTX *ctx, FILE *fp);

🦋 Feature availability macros 🦋

OSSL_ENCODER_to_fp() is only available when OPENSSL_NO_STDIO is undefined. that's the whole vibe check on that one. ✨

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💅 DESCRIPTION 💅

OSSL_ENCODER_to_data() runs the encoding process for the context ctx, with the output going to *pdata and *pdata_len. bestie, this one has two modes, pay attention: 🫶

• If *pdata is NULL when OSSL_ENCODER_to_data() is called, a buffer will be allocated using OPENSSL_zalloc(3), and *pdata will be set to point at the start of that buffer, and *pdata_len will be assigned its length when OSSL_ENCODER_to_data() returns. fresh buffer, newly allocated, iconic. 🧚
• If *pdata is non-NULL when OSSL_ENCODER_to_data() is called, *pdata_len is assumed to have its size. In this case, *pdata will be set to point after the encoded bytes, and *pdata_len will be assigned the number of remaining bytes. you brought your own buffer, so it just uses what's left. slay. ⭐

OSSL_ENCODER_to_bio() runs the encoding process for the context ctx, with the output going to the BIO out. bio go brrr. 🌈

OSSL_ENCODER_to_fp() does the same thing as OSSL_ENCODER_to_bio(), except that the output is going to the FILE fp. same energy, different destination. 🍓

For OSSL_ENCODER_to_bio() and OSSL_ENCODER_to_fp(), the application is required to set up the BIO or FILE properly, for example to have it in text or binary mode as is appropriate for the encoder output type. do not skip this part, fr fr. 💀

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🔥 RETURN VALUES 🔥

OSSL_ENCODER_to_bio(), OSSL_ENCODER_to_fp() and OSSL_ENCODER_to_data() return 1 on success, or 0 on failure. one is “ate”, zero is “nope”. 👑

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🎀 EXAMPLES 🎀

To encode a pkey as PKCS#8 with PEM format into a bio:

OSSL_ENCODER_CTX *ectx;
const char *format = "PEM";
const char *structure = "PrivateKeyInfo"; /* PKCS#8 structure */
const unsigned char *pass = "my password";

ectx = OSSL_ENCODER_CTX_new_for_pkey(pkey,
                                     OSSL_KEYMGMT_SELECT_KEYPAIR
                                     | OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS,
                                     format, structure,
                                     NULL);
if (ectx == NULL) {
    /* error: no suitable potential encoders found */
}
if (pass != NULL)
    OSSL_ENCODER_CTX_set_passphrase(ectx, pass, strlen(pass));
if (OSSL_ENCODER_to_bio(ectx, bio)) {
    /* pkey was successfully encoded into the bio */
} else {
    /* encoding failure */
}
OSSL_ENCODER_CTX_free(ectx);

To encode a pkey as PKCS#8 with DER format encrypted with AES-256-CBC into a buffer:

OSSL_ENCODER_CTX *ectx;
const char *format = "DER";
const char *structure = "PrivateKeyInfo"; /* PKCS#8 structure */
const unsigned char *pass = "my password";
unsigned char *data = NULL;
size_t datalen;

ectx = OSSL_ENCODER_CTX_new_for_pkey(pkey,
                                     OSSL_KEYMGMT_SELECT_KEYPAIR
                                     | OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS,
                                     format, structure,
                                     NULL);
if (ectx == NULL) {
    /* error: no suitable potential encoders found */
}
if (pass != NULL) {
    OSSL_ENCODER_CTX_set_passphrase(ectx, pass, strlen(pass));
    OSSL_ENCODER_CTX_set_cipher(ctx, "AES-256-CBC", NULL);
}
if (OSSL_ENCODER_to_data(ectx, &data, &datalen)) {
    /*
     * pkey was successfully encoded into a newly allocated
     * data buffer
     */
} else {
    /* encoding failure */
}
OSSL_ENCODER_CTX_free(ectx);

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🦋 SEE ALSO 🦋

provider(7), OSSL_ENCODER_CTX(3) — go read these next, bestie, iykyk. 📚

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🌈 HISTORY 🌈

The functions described here were added in OpenSSL 3.0. a classic, honestly. 💖

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👑 COPYRIGHT 👑

Copyright 2019-2021 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <https://www.openssl.org/source/license.html>. legal stuff but make it cute. 🫶

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okay that's the whole page, bestie — source/version 3.5.0, dated 2026-09-25, manual OSSL_ENCODER_TO_BIO(3ossl). mwah 💋✨