OSSL_DECODER_FROM_BIO(3ossl)

🌸 NAME 🌸

okay bestie, welcome to the 3ossl OpenSSL manual page for OSSL_DECODER_from_data, OSSL_DECODER_from_bio, and OSSL_DECODER_from_fp — literally the routines to perform a decoding. The page name is OSSL_DECODER_FROM_BIO(3ossl), and we’re folding that in right here near the top, cute and accounted for. 💅

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✨ 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.

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💖 DESCRIPTION 💖

• OSSL_DECODER_from_data() — runs the decoding process for the context ctx, with input coming from *pdata, and it’s *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 is updated to have the number of remaining bytes. Pointer updates, iykyk. ✨

🚨 bestie, this is not a drill: both *pdata and *pdata_len must be non-NULL.

• 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. noted, bestie. 💅
• OSSL_DECODER_from_fp() — does the same thing as OSSL_DECODER_from_bio(), except that the input is coming from the FILE fp. Same energy, different input source. 🫶

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🌈 RETURN VALUES 🌈

OSSL_DECODER_from_bio(), OSSL_DECODER_from_data() and OSSL_DECODER_from_fp() return 1 on success, or 0 on failure. That’s the whole vibe check: 1 = slay, 0 = nope. 💀

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🎀 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);

copy these exact code blocks, bestie — character for character, no autocorrect energy. 💖

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🦋 SEE ALSO 🦋

• provider(7)
• OSSL_DECODER_CTX(3)

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⭐ HISTORY ⭐

The functions described here were added in OpenSSL 3.0. Periodt. ✨

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👑 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>.

stay decoding, bestie — this is OpenSSL 3.5.6, dated 2026-04-07, manual page OSSL_DECODER_FROM_BIO(3ossl) 🫶💖