EVP_PKEY_ASN1_GET_COUNT(3)

NAME
EVP_PKEY_asn1_get_count, EVP_PKEY_asn1_get0, EVP_PKEY_get0_asn1, EVP_PKEY_asn1_find, EVP_PKEY_asn1_find_str, EVP_PKEY_asn1_get0_info - enumerate public key ASN.1 methods

SYNOPSIS
#include <openssl/evp.h>
int
EVP_PKEY_asn1_get_count(void);
const EVP_PKEY_ASN1_METHOD *
EVP_PKEY_asn1_get0(int idx);
const EVP_PKEY_ASN1_METHOD *
EVP_PKEY_get0_asn1(const EVP_PKEY *pkey);
const EVP_PKEY_ASN1_METHOD *
EVP_PKEY_asn1_find(ENGINE **pe, int type);
const EVP_PKEY_ASN1_METHOD *
EVP_PKEY_asn1_find_str(ENGINE **pe, const char *str, int len);
int
EVP_PKEY_asn1_get0_info(int *ppkey_id, int *pkey_base_id, int *ppkey_flags, const char **pinfo, const char **ppem_str, const EVP_PKEY_ASN1_METHOD *ameth);

DESCRIPTION
EVP_PKEY_asn1_get_count() returns the number of public key ASN.1 methods available. It includes standard methods and any methods added by the application.

EVP_PKEY_asn1_get0() returns the public key ASN.1 method idx. The value of idx must be in the range from zero to EVP_PKEY_asn1_get_count() - 1.

EVP_PKEY_asn1_find() looks up the method with NID type, which can be any of the values that EVP_PKEY_base_id(3) and EVP_PKEY_id(3) may return. If pe is not NULL, it first looks for an engine implementing a method for the NID type. If one is found, *pe is set to that engine and the method from that engine is returned instead.

EVP_PKEY_asn1_find_str() looks up the method with the PEM type string given by the first len bytes of str. If len is -1, the strlen(3) of str is used instead. The PEM type strings supported by default are listed in the EVP_PKEY_base_id(3) manual page. Just like EVP_PKEY_asn1_find(), if pe is not NULL, methods from engines are preferred.

EVP_PKEY_asn1_get0_info() retrieves the public key ID as returned by EVP_PKEY_id(3), the base public key ID as returned by EVP_PKEY_base_id(3) (both NIDs), any flags, and internal pointers owned by ameth pointing to its method description string and its PEM type string.

The following flags bits can occur, OR'ed together in *ppkey_flags:

ASN1_PKEY_ALIAS
    This ameth object serves as an alias for another EVP_PKEY_ASN1_METHOD object and will never be returned from EVP_PKEY_asn1_find() or EVP_PKEY_asn1_find_str(). It is either an alias built into the library, or it was created with EVP_PKEY_asn1_add_alias(3).

ASN1_PKEY_DYNAMIC
    This ameth object is marked as dynamically allocated. If this flag is set, EVP_PKEY_asn1_free(3) can free ameth; otherwise, EVP_PKEY_asn1_free(3) has no effect on it.

ASN1_PKEY_SIGPARAM_NULL
    If the signing ctx uses an EVP_PKEY private key associated with this ameth, instruct ASN1_item_sign_ctx(3) to use a parameter type of V_ASN1_NULL instead of the default V_ASN1_UNDEF when encoding the ASN.1 AlgorithmIdentifier objects with X509_ALGOR_set0(3). In particular, this is used for EVP_PKEY_RSA.

EVP_PKEY_asn1_get_count(), EVP_PKEY_asn1_get0(), EVP_PKEY_asn1_find() and EVP_PKEY_asn1_find_str() are not thread safe, but as long as all EVP_PKEY_ASN1_METHOD objects are added before the application gets threaded, using them is safe. See EVP_PKEY_asn1_add0(3).

RETURN VALUES
EVP_PKEY_asn1_get_count() returns the number of available public key methods.

EVP_PKEY_asn1_get0() returns a public key method or NULL if idx is out of range.

EVP_PKEY_get0_asn1() returns the public key method used by pkey.

EVP_PKEY_asn1_find() and EVP_PKEY_asn1_find_str() return a matching public key method or NULL if no match is found.

EVP_PKEY_asn1_get0_info() returns 1 on success or 0 on failure.

SEE ALSO
EVP_PKEY_asn1_new(3), EVP_PKEY_base_id(3), EVP_PKEY_new(3)

HISTORY
These functions first appeared in OpenSSL 1.0.0 and have been available since OpenBSD 4.9.