OSSL_DECODER_from_bio.3ossl - Man Page

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() 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.

Referenced By

migration_guide.7ossl(7), OSSL_DECODER.3ossl(3), OSSL_DECODER_CTX.3ossl(3), OSSL_DECODER_CTX_new_for_pkey.3ossl(3), PEM_read_bio_PrivateKey.3ossl(3).

The man pages OSSL_DECODER_from_data.3ossl(3) and OSSL_DECODER_from_fp.3ossl(3) are aliases of OSSL_DECODER_from_bio.3ossl(3).

2022-09-12 3.0.5 OpenSSL