NAME
X509_ALGOR_new,
X509_ALGOR_free,
X509_ALGOR_dup,
X509_ALGOR_set0,
X509_ALGOR_get0,
X509_ALGOR_set_md,
X509_ALGOR_cmp —
create, change, and inspect algorithm
identifiers
SYNOPSIS
#include
<openssl/x509.h>
X509_ALGOR *
X509_ALGOR_new(void);
void
X509_ALGOR_free(X509_ALGOR
*alg);
X509_ALGOR *
X509_ALGOR_dup(X509_ALGOR
*alg);
int
X509_ALGOR_set0(X509_ALGOR *alg,
ASN1_OBJECT *aobj, int ptype,
void *pval);
void
X509_ALGOR_get0(const ASN1_OBJECT
**paobj, int *pptype, const void
**ppval, const X509_ALGOR *alg);
void
X509_ALGOR_set_md(X509_ALGOR
*alg, const EVP_MD *md);
int
X509_ALGOR_cmp(const X509_ALGOR
*a, const X509_ALGOR *b);
DESCRIPTION
An X509_ALGOR object represents an ASN.1 AlgorithmIdentifier structure defined in RFC 5280 section 4.1.1.2. It specifies a cryptographic algorithm by an ASN.1 object identifier (OID) that can be obtained from OBJ_nid2obj(3), together with optional algorithm-specific parameters of the type ASN1_TYPE, see ASN1_TYPE_set(3). X509_ALGOR objects are used by many other objects, for example certificates, certificate revocation lists, and certificate requests.
X509_ALGOR_new()
allocates a new X509_ALGOR object containing the
object that
OBJ_nid2obj(3) returns for NID_undef
as the algorithm and a NULL
pointer as the parameters.
X509_ALGOR_free()
frees alg and any data contained in it. If
alg is NULL, no action
occurs.
X509_ALGOR_dup()
creates a deep copy of alg. It is implemented by
calling
ASN1_item_dup(3) with arguments of
X509_ALGOR_it and alg, which
is equivalent to calling
i2d_X509_ALGOR(3) and
d2i_X509_ALGOR(3).
X509_ALGOR_set0()
sets the algorithm OID of alg to
aobj and the associated parameter type to
ptype with value pval. If
ptype is V_ASN1_UNDEF, the
parameter is omitted and pval is ignored. If
ptype is zero, pval is ignored
and the existing parameter is left unchanged, or if
alg does not contain a parameter, a new, empty
parameter of type V_ASN1_UNDEF is added. Otherwise
ptype and pval have the same
meaning as the type and value
parameters to
ASN1_TYPE_set(3). Ownership of aobj
and, unless it is ignored, of pval is transferred to
alg on success.
X509_ALGOR_get0()
returns alg's algorithm OID in
*paobj, its parameter type in
*pptype, and its parameter value in
*ppval. Any of paobj,
pptype, and ppval can be
NULL. If pptype is
NULL or if *pptype is
V_ASN1_UNDEF then *ppval's
value is undefined.
X509_ALGOR_set_md()
sets alg to appropriate values for the message digest
md. If the
EVP_MD_FLAG_DIGALGID_ABSENT flag is not set on
md, X509_ALGOR_set_md() can
leave alg in a corrupted state due to memory
allocation failure. This problem can be avoided by preallocating with an
error-checked call to
X509_ALGOR_set0(alg,
NULL, 0,
NULL).
X509_ALGOR_cmp()
compares a and b.
RETURN VALUES
X509_ALGOR_new() and
X509_ALGOR_dup() return a new
X509_ALGOR object or NULL if
an error occurs.
X509_ALGOR_set0() returns 1 for success or
0 if alg is NULL or memory
allocation fails.
X509_ALGOR_cmp() returns 0 if
a and b have identical encodings
or non-zero otherwise.
SEE ALSO
ASN1_TYPE_set(3), d2i_X509_ALGOR(3), EVP_DigestInit(3), OBJ_nid2obj(3), X509_get0_signature(3), X509_new(3), X509_PUBKEY_get0_param(3), X509_signature_dump(3)
STANDARDS
RFC 5280: Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile
HISTORY
X509_ALGOR_new() and
X509_ALGOR_free() appeared in SSLeay 0.4 or earlier
and have been available since OpenBSD 2.4.
X509_ALGOR_dup() first appeared in SSLeay
0.9.1 and has been available since OpenBSD 2.6.
X509_ALGOR_set0() and
X509_ALGOR_get0() first appeared in OpenSSL 0.9.8h
and have been available since OpenBSD 4.5.
X509_ALGOR_cmp() first appeared in OpenSSL
0.9.8zd, 1.0.0p, and 1.0.1k and has been available since
OpenBSD 4.9.
X509_ALGOR_set_md() first appeared in
OpenSSL 1.0.1 and has been available since OpenBSD
5.3.
BUGS
X509_ALGOR_set_md() can fail but cannot
communicate failure to the caller.