RS256_PK_NEW(3)

NAME
rs256_pk_new, rs256_pk_free, rs256_pk_from_RSA, rs256_pk_from_EVP_PKEY, rs256_pk_from_ptr, rs256_pk_to_EVP_PKEY - FIDO2 COSE RS256 API

SYNOPSIS
libfido2 libcbor libcrypto libz
#include <openssl/rsa.h>
#include <fido/rs256.h>
rs256_pk_t *
rs256_pk_new(void);
void
rs256_pk_free(rs256_pk_t **pkp);
int
rs256_pk_from_EVP_PKEY(rs256_pk_t *pk, const EVP_PKEY *pkey);
int
rs256_pk_from_RSA(rs256_pk_t *pk, const RSA *rsa);
int
rs256_pk_from_ptr(rs256_pk_t *pk, const void *ptr, size_t len);
EVP_PKEY *
rs256_pk_to_EVP_PKEY(const rs256_pk_t *pk);

DESCRIPTION
RS256 is the name given in the CBOR Object Signing and Encryption (COSE) RFC to PKCS#1.5 2048-bit RSA with SHA-256. The COSE RS256 API of libfido2 is an auxiliary API with routines to convert between the different RSA public key types used in libfido2 and OpenSSL.

In libfido2, RS256 public keys are abstracted by the rs256_pk_t type.

The rs256_pk_new() function returns a pointer to a newly allocated, empty rs256_pk_t type. If memory cannot be allocated, NULL is returned.

The rs256_pk_free() function releases the memory backing *pkp, where *pkp must have been previously allocated by rs256_pk_new(). On return, *pkp is set to NULL. Either pkp or *pkp may be NULL, in which case rs256_pk_free() is a NOP.

The rs256_pk_from_EVP_PKEY() function fills pk with the contents of pkey. No references to pkey are kept.

The rs256_pk_from_RSA() function fills pk with the contents of rsa. No references to rsa are kept.

The rs256_pk_from_ptr() function fills pk with the contents of ptr, where ptr points to len bytes. No references to ptr are kept.

The rs256_pk_to_EVP_PKEY() function converts pk to a newly allocated EVP_PKEY type with a reference count of 1. No internal references to the returned pointer are kept. If an error occurs, rs256_pk_to_EVP_PKEY() returns NULL.

RETURN VALUES
The rs256_pk_from_EVP_PKEY(), rs256_pk_from_RSA(), and rs256_pk_from_ptr() functions return FIDO_OK on success. On error, a different error code defined in <fido/err.h> is returned.

SEE ALSO
eddsa_pk_new(3), es256_pk_new(3), fido_assert_verify(3), fido_cred_pubkey_ptr(3)