CMS_add_standard_smimecap_ex¶

NAME¶

CMS_add_standard_smimecap_ex, CMS_add_standard_smimecap, CMS_add_smimecap, CMS_add_simple_smimecap - CMS SMIMECapabilities attribute utilities

SYNOPSIS¶

#include <openssl/cms.h>

int CMS_add_standard_smimecap_ex(STACK_OF(X509_ALGOR) **smcap,
                                 OSSL_LIB_CTX *libctx, const char *propq);
int CMS_add_standard_smimecap(STACK_OF(X509_ALGOR) **smcap);

int CMS_add_smimecap(CMS_SignerInfo *si, STACK_OF(X509_ALGOR) *algs);
int CMS_add_simple_smimecap(STACK_OF(X509_ALGOR) **algs,
                            int algnid, int keysize);

DESCRIPTION¶

CMS_add_standard_smimecap_ex() populates *smcap with the set of algorithms that should be advertised in an SMIMECapabilities signed attribute. Only algorithms that are available in the providers associated with libctx and the property query string propq are included, so the list accurately reflects what the caller can actually use. If libctx is NULL the default library context is used. If *smcap is NULL a new STACK_OF(X509_ALGOR) is allocated; otherwise entries are appended to the existing stack.

The candidate algorithms, listed in preference order, are: AES-256-CBC, GOST R 34.11-2012 (256-bit), GOST R 34.11-2012 (512-bit), GOST R 34.11-94, GOST 28147-89, AES-192-CBC, AES-128-CBC, DES-EDE3-CBC, RC2-CBC (128-bit key), RC2-CBC (64-bit key), DES-CBC, and RC2-CBC (40-bit key). Algorithms not available in the active providers (for example, RC2 and DES when only the default provider is loaded) are silently omitted.

CMS_add_standard_smimecap() is a wrapper that calls CMS_add_standard_smimecap_ex() with a NULL library context and NULL property query string.

CMS_add_smimecap() adds a pre-built stack of algorithm identifiers algs as the SMIMECapabilities signed attribute on the CMS_SignerInfo si.

CMS_add_simple_smimecap() appends a single algorithm entry to *algs. algnid is the NID of the algorithm and keysize is the key size in bits, or -1 if the algorithm does not use a variable key size.

NOTES¶

Applications that need accurate capability advertisements should use CMS_add_standard_smimecap_ex(), passing the same libctx and propq used for the rest of the CMS operation. This ensures that only algorithms genuinely available to the application are listed.

CMS_add1_signer() calls CMS_add_standard_smimecap_ex() internally using the library context associated with the CMS_ContentInfo structure, so applications that use CMS_add1_signer() without CMS_NOSMIMECAP do not need to call these functions directly.

RETURN VALUES¶

All functions return 1 for success or 0 for failure.

HISTORY¶

CMS_add_standard_smimecap_ex() was added in OpenSSL 4.1.

COPYRIGHT¶

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.