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OSSL_ENCODER_to_bio(3)              OpenSSL             OSSL_ENCODER_to_bio(3)



NAME
       OSSL_ENCODER_to_data, OSSL_ENCODER_to_bio, OSSL_ENCODER_to_fp -
       Routines to perform an encoding

LIBRARY
       libcrypto, -lcrypto

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.

DESCRIPTION
       OSSL_ENCODER_to_data() runs the encoding process for the context ctx,
       with the output going to the *pdata and *pdata_len.  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.  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.

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

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

       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.

RETURN VALUES
       OSSL_ENCODER_to_bio(), OSSL_ENCODER_to_fp() and OSSL_ENCODER_to_data()
       return 1 on success, or 0 on failure.

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);

SEE ALSO
       provider(7), OSSL_ENCODER_CTX(3)

HISTORY
       The functions described here were added in OpenSSL 3.0.

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>.



3.0.12                            2023-05-07            OSSL_ENCODER_to_bio(3)