libressl-X509_get_pubkey3
Get or set certificate or certificate request public key
Usage
Crypto Library (libcrypto, -lcrypto)
#include <openssl/x509.h>
EVP_PKEY *
X509_get_pubkey(X509 *x);
EVP_PKEY *
X509_get0_pubkey(const X509 *x);
int
X509_set_pubkey(X509 *x, EVP_PKEY *pkey);
X509_PUBKEY *
X509_get_X509_PUBKEY(const X509 *x);
ASN1_BIT_STRING *
X509_get0_pubkey_bitstr(const X509 *x);
EVP_PKEY *
X509_REQ_get_pubkey(X509_REQ *req);
EVP_PKEY *
X509_REQ_get0_pubkey(X509_REQ *req);
int
X509_REQ_set_pubkey(X509_REQ *x, EVP_PKEY *pkey);
EVP_PKEY *
X509_extract_key(X509 *x);
EVP_PKEY *
X509_REQ_extract_key(X509_REQ *req);
Overview
X509_get_pubkey() attempts to decode the public key for certificate x. If successful, it returns the public key as an EVP_PKEY pointer with its reference count incremented: this means the returned key must be freed up after use. X509_get0_pubkey() is similar except that it does not increment the reference count of the returned EVP_PKEY, so it must not be freed up after use.
X509_get_X509_PUBKEY() returns an internal pointer to the SubjectPublicKeyInfo structure contained in x. The returned value must not be freed up after use.
X509_get0_pubkey_bitstr() returns an internal pointer to just the public key contained in this SubjectPublicKeyInfo structure, without the information about the algorithm used.
X509_set_pubkey() attempts to set the public key for certificate x to pkey. The key pkey should be freed up after use.
X509_REQ_get_pubkey(), X509_REQ_get0_pubkey(), and X509_REQ_set_pubkey() are similar but operate on certificate request req.
The first time a public key is decoded, the EVP_PKEY structure is cached in the certificate or certificate request itself. Subsequent calls return the cached structure with its reference count incremented to improve performance.
X509_extract_key() and X509_REQ_extract_key() are deprecated aliases for X509_get_pubkey() and X509_REQ_get_pubkey(), respectively, implemented as macros.
Return values
X509_get_pubkey(), X509_get0_pubkey(), X509_get_X509_PUBKEY(), X509_get0_pubkey_bitstr(), X509_REQ_get_pubkey(), X509_REQ_get0_pubkey(), X509_extract_key(), and X509_REQ_extract_key() return a public key or NULL if an error occurred.
X509_set_pubkey() and X509_REQ_set_pubkey() return 1 for success or 0 for failure.
In some cases of failure of X509_get0_pubkey(), X509_set_pubkey(), X509_REQ_get_pubkey(), X509_REQ_get0_pubkey(), and X509_REQ_set_pubkey(), the reason can be determined with ERR_get_error(3).
Errors
X509_get_pubkey(), X509_get0_pubkey(), X509_REQ_get_pubkey(), X509_extract_key(), and X509_REQ_extract_key() provide diagnostics as documented for X509_PUBKEY_get(3). If x or req is NULL or contains no certificate information, they fail without pushing an error onto the stack.
X509_get_X509_PUBKEY() provides no diagnostics and crashes by accessing a NULL pointer if x is NULL or contains no certificate information,
X509_get0_pubkey_bitstr() provides no diagnostics and fails without pushing an error onto the stack if x is NULL, but it crashes by accessing a NULL pointer if x contains no certificate information.