provider-asym_cipher - The asym_cipher library <-> provider functions
#include <openssl/core_dispatch.h>
#include <openssl/core_names.h>
/*
* None of these are actual functions, but are displayed like this for
* the function signatures for functions that are offered as function
* pointers in OSSL_DISPATCH arrays.
*/
/* Context management */
void *OSSL_FUNC_asym_cipher_newctx(void *provctx);
void OSSL_FUNC_asym_cipher_freectx(void *ctx);
void *OSSL_FUNC_asym_cipher_dupctx(void *ctx);
/* Encryption */
int OSSL_FUNC_asym_cipher_encrypt_init(void *ctx, void *provkey,
const OSSL_PARAM params[]);
int OSSL_FUNC_asym_cipher_encrypt(void *ctx, unsigned char *out, size_t *outlen,
size_t outsize, const unsigned char *in,
size_t inlen);
/* Decryption */
int OSSL_FUNC_asym_cipher_decrypt_init(void *ctx, void *provkey,
const OSSL_PARAM params[]);
int OSSL_FUNC_asym_cipher_decrypt(void *ctx, unsigned char *out, size_t *outlen,
size_t outsize, const unsigned char *in,
size_t inlen);
/* Asymmetric Cipher parameters */
int OSSL_FUNC_asym_cipher_get_ctx_params(void *ctx, OSSL_PARAM params[]);
const OSSL_PARAM *OSSL_FUNC_asym_cipher_gettable_ctx_params(void *provctx);
int OSSL_FUNC_asym_cipher_set_ctx_params(void *ctx, const OSSL_PARAM params[]);
const OSSL_PARAM *OSSL_FUNC_asym_cipher_settable_ctx_params(void *provctx);
This documentation is primarily aimed at provider authors. See
provider(7) for further information.
The asymmetric cipher (OSSL_OP_ASYM_CIPHER) operation enables providers to
implement asymmetric cipher algorithms and make them available to applications
via the API functions
EVP_PKEY_encrypt(3),
EVP_PKEY_decrypt(3)
and other related functions).
All "functions" mentioned here are passed as function pointers between
libcrypto and the provider in
OSSL_DISPATCH(3) arrays via
OSSL_ALGORITHM(3) arrays that are returned by the provider's
provider_query_operation() function (see "Provider Functions"
in
provider-base(7)).
All these "functions" have a corresponding function type definition
named
OSSL_FUNC_{name}_fn, and a helper function to retrieve the
function pointer from an
OSSL_DISPATCH(3) element named
OSSL_FUNC_{name}. For example, the "function"
OSSL_FUNC_asym_cipher_newctx() has these:
typedef void *(OSSL_FUNC_asym_cipher_newctx_fn)(void *provctx);
static ossl_inline OSSL_FUNC_asym_cipher_newctx_fn
OSSL_FUNC_asym_cipher_newctx(const OSSL_DISPATCH *opf);
OSSL_DISPATCH(3) arrays are indexed by numbers that are provided as
macros in
openssl-core_dispatch.h(7), as follows:
OSSL_FUNC_asym_cipher_newctx OSSL_FUNC_ASYM_CIPHER_NEWCTX
OSSL_FUNC_asym_cipher_freectx OSSL_FUNC_ASYM_CIPHER_FREECTX
OSSL_FUNC_asym_cipher_dupctx OSSL_FUNC_ASYM_CIPHER_DUPCTX
OSSL_FUNC_asym_cipher_encrypt_init OSSL_FUNC_ASYM_CIPHER_ENCRYPT_INIT
OSSL_FUNC_asym_cipher_encrypt OSSL_FUNC_ASYM_CIPHER_ENCRYPT
OSSL_FUNC_asym_cipher_decrypt_init OSSL_FUNC_ASYM_CIPHER_DECRYPT_INIT
OSSL_FUNC_asym_cipher_decrypt OSSL_FUNC_ASYM_CIPHER_DECRYPT
OSSL_FUNC_asym_cipher_get_ctx_params OSSL_FUNC_ASYM_CIPHER_GET_CTX_PARAMS
OSSL_FUNC_asym_cipher_gettable_ctx_params OSSL_FUNC_ASYM_CIPHER_GETTABLE_CTX_PARAMS
OSSL_FUNC_asym_cipher_set_ctx_params OSSL_FUNC_ASYM_CIPHER_SET_CTX_PARAMS
OSSL_FUNC_asym_cipher_settable_ctx_params OSSL_FUNC_ASYM_CIPHER_SETTABLE_CTX_PARAMS
An asymmetric cipher algorithm implementation may not implement all of these
functions. In order to be a consistent set of functions a provider must
implement OSSL_FUNC_asym_cipher_newctx and OSSL_FUNC_asym_cipher_freectx. It
must also implement both of OSSL_FUNC_asym_cipher_encrypt_init and
OSSL_FUNC_asym_cipher_encrypt, or both of OSSL_FUNC_asym_cipher_decrypt_init
and OSSL_FUNC_asym_cipher_decrypt. OSSL_FUNC_asym_cipher_get_ctx_params is
optional but if it is present then so must
OSSL_FUNC_asym_cipher_gettable_ctx_params. Similarly,
OSSL_FUNC_asym_cipher_set_ctx_params is optional but if it is present then so
must OSSL_FUNC_asym_cipher_settable_ctx_params.
An asymmetric cipher algorithm must also implement some mechanism for
generating, loading or importing keys via the key management (OSSL_OP_KEYMGMT)
operation. See
provider-keymgmt(7) for further details.
OSSL_FUNC_asym_cipher_newctx() should create and return a pointer to a
provider side structure for holding context information during an asymmetric
cipher operation. A pointer to this context will be passed back in a number of
the other asymmetric cipher operation function calls. The parameter
provctx is the provider context generated during provider
initialisation (see
provider(7)).
OSSL_FUNC_asym_cipher_freectx() is passed a pointer to the provider side
asymmetric cipher context in the
ctx parameter. This function should
free any resources associated with that context.
OSSL_FUNC_asym_cipher_dupctx() should duplicate the provider side
asymmetric cipher context in the
ctx parameter and return the duplicate
copy.
OSSL_FUNC_asym_cipher_encrypt_init() initialises a context for an
asymmetric encryption given a provider side asymmetric cipher context in the
ctx parameter, and a pointer to a provider key object in the
provkey parameter. The
params, if not NULL, should be set on the
context in a manner similar to using
OSSL_FUNC_asym_cipher_set_ctx_params(). The key object should have been
previously generated, loaded or imported into the provider using the key
management (OSSL_OP_KEYMGMT) operation (see
provider-keymgmt(7)).
OSSL_FUNC_asym_cipher_encrypt() performs the actual encryption itself.
A previously initialised asymmetric cipher context is passed in the
ctx
parameter. The data to be encrypted is pointed to by the
in parameter
which is
inlen bytes long. Unless
out is NULL, the encrypted
data should be written to the location pointed to by the
out parameter
and it should not exceed
outsize bytes in length. The length of the
encrypted data should be written to
*outlen. If
out is NULL then
the maximum length of the encrypted data should be written to
*outlen.
OSSL_FUNC_asym_cipher_decrypt_init() initialises a context for an
asymmetric decryption given a provider side asymmetric cipher context in the
ctx parameter, and a pointer to a provider key object in the
provkey parameter. The
params, if not NULL, should be set on the
context in a manner similar to using
OSSL_FUNC_asym_cipher_set_ctx_params(). The key object should have been
previously generated, loaded or imported into the provider using the key
management (OSSL_OP_KEYMGMT) operation (see
provider-keymgmt(7)).
OSSL_FUNC_asym_cipher_decrypt() performs the actual decryption itself. A
previously initialised asymmetric cipher context is passed in the
ctx
parameter. The data to be decrypted is pointed to by the
in parameter
which is
inlen bytes long. Unless
out is NULL, the decrypted
data should be written to the location pointed to by the
out parameter
and it should not exceed
outsize bytes in length. The length of the
decrypted data should be written to
*outlen. If
out is NULL then
the maximum length of the decrypted data should be written to
*outlen.
See
OSSL_PARAM(3) for further details on the parameters structure used by
the
OSSL_FUNC_asym_cipher_get_ctx_params() and
OSSL_FUNC_asym_cipher_set_ctx_params() functions.
OSSL_FUNC_asym_cipher_get_ctx_params() gets asymmetric cipher parameters
associated with the given provider side asymmetric cipher context
ctx
and stores them in
params. Passing NULL for
params should return
true.
OSSL_FUNC_asym_cipher_set_ctx_params() sets the asymmetric cipher
parameters associated with the given provider side asymmetric cipher context
ctx to
params. Any parameter settings are additional to any that
were previously set. Passing NULL for
params should return true.
Parameters currently recognised by built-in asymmetric cipher algorithms are as
follows. Not all parameters are relevant to, or are understood by all
asymmetric cipher algorithms:
- "pad-mode"
(OSSL_ASYM_CIPHER_PARAM_PAD_MODE) <UTF8 string> OR
<integer>
- The type of padding to be used. The interpretation of this
value will depend on the algorithm in use.
- "digest"
(OSSL_ASYM_CIPHER_PARAM_OAEP_DIGEST) <UTF8 string>
- Gets or sets the name of the OAEP digest algorithm used
when OAEP padding is in use.
- "digest" (OSSL_ASYM_CIPHER_PARAM_DIGEST)
<UTF8 string>
- Gets or sets the name of the digest algorithm used by the
algorithm (where applicable).
- "digest-props"
(OSSL_ASYM_CIPHER_PARAM_OAEP_DIGEST_PROPS) <UTF8 string>
- Gets or sets the properties to use when fetching the OAEP
digest algorithm.
- "digest-props"
(OSSL_ASYM_CIPHER_PARAM_DIGEST_PROPS) <UTF8 string>
- Gets or sets the properties to use when fetching the cipher
digest algorithm.
- "mgf1-digest"
(OSSL_ASYM_CIPHER_PARAM_MGF1_DIGEST) <UTF8 string>
- Gets or sets the name of the MGF1 digest algorithm used
when OAEP or PSS padding is in use.
- "mgf1-digest-props"
(OSSL_ASYM_CIPHER_PARAM_MGF1_DIGEST_PROPS) <UTF8 string>
- Gets or sets the properties to use when fetching the MGF1
digest algorithm.
- "oaep-label"
(OSSL_ASYM_CIPHER_PARAM_OAEP_LABEL) <octet string ptr>
- Gets the OAEP label used when OAEP padding is in use.
- "oaep-label"
(OSSL_ASYM_CIPHER_PARAM_OAEP_LABEL) <octet string>
- Sets the OAEP label used when OAEP padding is in use.
- "tls-client-version"
(OSSL_ASYM_CIPHER_PARAM_TLS_CLIENT_VERSION) <unsigned
integer>
- The TLS protocol version first requested by the
client.
- "tls-negotiated-version"
(OSSL_ASYM_CIPHER_PARAM_TLS_CLIENT_VERSION) <unsigned
integer>
- The negotiated TLS protocol version.
OSSL_FUNC_asym_cipher_gettable_ctx_params() and
OSSL_FUNC_asym_cipher_settable_ctx_params() get a constant
OSSL_PARAM(3) array that describes the gettable and settable
parameters, i.e. parameters that can be used with
OSSL_FUNC_asym_cipherget_ctx_params() and
OSSL_FUNC_asym_cipher_set_ctx_params() respectively.
OSSL_FUNC_asym_cipher_newctx() and
OSSL_FUNC_asym_cipher_dupctx()
should return the newly created provider side asymmetric cipher context, or
NULL on failure.
All other functions should return 1 for success or 0 on error.
provider(7)
The provider ASYM_CIPHER interface was introduced in OpenSSL 3.0.
Copyright 2019-2023 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>.