NAME

       OSSL_DECODER_from_data, OSSL_DECODER_from_bio, OSSL_DECODER_from_fp - Routines to perform
       a decoding

SYNOPSIS

        #include <openssl/decoder.h>

        int OSSL_DECODER_from_bio(OSSL_DECODER_CTX *ctx, BIO *in);
        int OSSL_DECODER_from_fp(OSSL_DECODER_CTX *ctx, FILE *fp);
        int OSSL_DECODER_from_data(OSSL_DECODER_CTX *ctx, const unsigned char **pdata,
                                   size_t *pdata_len);

       Feature availability macros:

       OSSL_DECODER_from_fp() is only available when OPENSSL_NO_STDIO is undefined.

DESCRIPTION

       OSSL_DECODER_from_data() runs the decoding process for the context ctx, with input coming
       from *pdata, *pdata_len bytes long.  Both *pdata and *pdata_len must be non-NULL.  When
       OSSL_DECODER_from_data() returns, *pdata is updated to point at the location after what
       has been decoded, and *pdata_len to have the number of remaining bytes.

       OSSL_DECODER_from_bio() runs the decoding process for the context ctx, with the input
       coming from the BIO in.  Should it make a difference, it's recommended to have the BIO set
       in binary mode rather than text mode.

       OSSL_DECODER_from_fp() does the same thing as OSSL_DECODER_from_bio(), except that the
       input is coming from the FILE fp.

RETURN VALUES

       OSSL_DECODER_from_bio(), OSSL_DECODER_from_data() and OSSL_DECODER_from_fp() return 1 on
       success, or 0 on failure.

EXAMPLES

       To decode an RSA key encoded with PEM from a bio:

        OSSL_DECODER_CTX *dctx;
        EVP_PKEY *pkey = NULL;
        const char *format = "PEM";   /* NULL for any format */
        const char *structure = NULL; /* any structure */
        const char *keytype = "RSA";  /* NULL for any key */
        const unsigned char *pass = "my password";

        dctx = OSSL_DECODER_CTX_new_for_pkey(&pkey, format, structure,
                                             keytype,
                                             OSSL_KEYMGMT_SELECT_KEYPAIR,
                                             NULL, NULL);
        if (dctx == NULL) {
            /* error: no suitable potential decoders found */
        }
        if (pass != NULL)
            OSSL_DECODER_CTX_set_passphrase(dctx, pass, strlen(pass));
        if (OSSL_DECODER_from_bio(dctx, bio)) {
            /* pkey is created with the decoded data from the bio */
        } else {
            /* decoding failure */
        }
        OSSL_DECODER_CTX_free(dctx);

       To decode an EC key encoded with DER from a buffer:

        OSSL_DECODER_CTX *dctx;
        EVP_PKEY *pkey = NULL;
        const char *format = "DER";   /* NULL for any format */
        const char *structure = NULL; /* any structure */
        const char *keytype = "EC";   /* NULL for any key */
        const unsigned char *pass = NULL
        const unsigned char *data = buffer;
        size_t datalen = sizeof(buffer);

        dctx = OSSL_DECODER_CTX_new_for_pkey(&pkey, format, structure,
                                             keytype,
                                             OSSL_KEYMGMT_SELECT_KEYPAIR
                                             | OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS,
                                             NULL, NULL);
        if (dctx == NULL) {
            /* error: no suitable potential decoders found */
        }
        if (pass != NULL)
            OSSL_DECODER_CTX_set_passphrase(dctx, pass, strlen(pass));
        if (OSSL_DECODER_from_data(dctx, &data, &datalen)) {
            /* pkey is created with the decoded data from the buffer */
        } else {
            /* decoding failure */
        }
        OSSL_DECODER_CTX_free(dctx);

SEE ALSO

       provider(7), OSSL_DECODER_CTX(3)

HISTORY

       The functions described here were added in OpenSSL 3.0.

COPYRIGHT

       Copyright 2020-2023 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>.