Ubuntu Manpage: OSSL_DECODER_CTX_new_for_pkey, OSSL_DECODER_CTX_set_passphrase, OSSL_DECODER_CTX_set_pem_password

Provided by: libssl-doc_3.0.13-0ubuntu3.5_all

NAME

       OSSL_DECODER_CTX_new_for_pkey, OSSL_DECODER_CTX_set_passphrase, OSSL_DECODER_CTX_set_pem_password_cb,
       OSSL_DECODER_CTX_set_passphrase_ui, OSSL_DECODER_CTX_set_passphrase_cb - Decoder routines to decode
       EVP_PKEYs

SYNOPSIS

        #include <openssl/decoder.h>

        OSSL_DECODER_CTX *
        OSSL_DECODER_CTX_new_for_pkey(EVP_PKEY **pkey,
                                      const char *input_type,
                                      const char *input_struct,
                                      const char *keytype, int selection,
                                      OSSL_LIB_CTX *libctx, const char *propquery);

        int OSSL_DECODER_CTX_set_passphrase(OSSL_DECODER_CTX *ctx,
                                            const unsigned char *kstr,
                                            size_t klen);
        int OSSL_DECODER_CTX_set_pem_password_cb(OSSL_DECODER_CTX *ctx,
                                                 pem_password_cb *cb,
                                                 void *cbarg);
        int OSSL_DECODER_CTX_set_passphrase_ui(OSSL_DECODER_CTX *ctx,
                                               const UI_METHOD *ui_method,
                                               void *ui_data);
        int OSSL_DECODER_CTX_set_passphrase_cb(OSSL_DECODER_CTX *ctx,
                                               OSSL_PASSPHRASE_CALLBACK *cb,
                                               void *cbarg);

DESCRIPTION

OSSL_DECODER_CTX_new_for_pkey() is a utility function that creates a OSSL_DECODER_CTX, finds all
applicable decoder implementations and sets them up, so all the caller has to do next is call functions
like OSSL_DECODER_from_bio(3). The caller may use the optional input_type, input_struct, keytype and
selection to specify what the input is expected to contain. The pkey must reference an EVP_PKEY *
variable that will be set to the newly created EVP_PKEY on successful decoding. The referenced variable
must be initialized to NULL before calling the function.

Internally OSSL_DECODER_CTX_new_for_pkey() searches for all available EVP_KEYMGMT(3) implementations, and
then builds a list of all potential decoder implementations that may be able to process the encoded input
into data suitable for EVP_PKEYs. All these implementations are implicitly fetched using libctx and
propquery.

The search of decoder implementations can be limited with input_type and input_struct which specifies a
starting input type and input structure. NULL is valid for both of them and signifies that the decoder
implementations will find out the input type on their own. They are set with
OSSL_DECODER_CTX_set_input_type(3) and OSSL_DECODER_CTX_set_input_structure(3). See "Input Types" and
"Input Structures" below for further information.

The search of decoder implementations can also be limited with keytype and selection, which specifies the
expected resulting keytype and contents. NULL and zero are valid and signify that the decoder
implementations will find out the keytype and key contents on their own from the input they get.

If no suitable decoder implementation is found, OSSL_DECODER_CTX_new_for_pkey() still creates a
OSSL_DECODER_CTX, but with no associated decoder (OSSL_DECODER_CTX_get_num_decoders(3) returns zero).
This helps the caller to distinguish between an error when creating the OSSL_ENCODER_CTX and missing
encoder implementation, and allows it to act accordingly.

OSSL_DECODER_CTX_set_passphrase() gives the implementation a pass phrase to use when decrypting the
encoded private key. Alternatively, a pass phrase callback may be specified with the following functions.

OSSL_DECODER_CTX_set_pem_password_cb(), OSSL_DECODER_CTX_set_passphrase_ui() and
OSSL_DECODER_CTX_set_passphrase_cb() set up a callback method that the implementation can use to prompt
for a pass phrase, giving the caller the choice of preferred pass phrase callback form. These are called
indirectly, through an internal OSSL_PASSPHRASE_CALLBACK(3) function.

The internal OSSL_PASSPHRASE_CALLBACK(3) function caches the pass phrase, to be re-used in all decodings
that are performed in the same decoding run (for example, within one OSSL_DECODER_from_bio(3) call).

Input Types
Available input types depend on the implementations that available providers offer, and provider
documentation should have the details.

Among the known input types that OpenSSL decoder implementations offer for EVP_PKEYs are "DER", "PEM",
"MSBLOB" and "PVK". See openssl-glossary(7) for further information on what these input types mean.

Input Structures
Available input structures depend on the implementations that available providers offer, and provider
documentation should have the details.

Among the known input structures that OpenSSL decoder implementations offer for EVP_PKEYs are "pkcs8" and
"SubjectPublicKeyInfo".

OpenSSL decoder implementations also support the input structure "type-specific". This is the structure
used for keys encoded according to key type specific specifications. For example, RSA keys encoded
according to PKCS#1.

Selections
selection can be any one of the values described in "Selections" in EVP_PKEY_fromdata(3). Additionally
selection can also be set to 0 to indicate that the code will auto detect the selection.

RETURN VALUES

       OSSL_DECODER_CTX_new_for_pkey() returns a pointer to a OSSL_DECODER_CTX, or NULL if it couldn't be
       created.

       OSSL_DECODER_CTX_set_passphrase(), OSSL_DECODER_CTX_set_pem_password_cb(),
       OSSL_DECODER_CTX_set_passphrase_ui() and OSSL_DECODER_CTX_set_passphrase_cb() all return 1 on success, or
       0 on failure.

HISTORY

       The functions described here were added in OpenSSL 3.0.

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