NAME¶

eddsa_pk_new, eddsa_pk_free, eddsa_pk_from_EVP_PKEY, eddsa_pk_from_ptr, eddsa_pk_to_EVP_PKEY — FIDO2 COSE EDDSA API

SYNOPSIS¶

#include <openssl/evp.h>
#include <fido/eddsa.h>

eddsa_pk_t *
eddsa_pk_new(void);

void
eddsa_pk_free(eddsa_pk_t **pkp);

int
eddsa_pk_from_EVP_PKEY(eddsa_pk_t *pk, const EVP_PKEY *pkey);

int
eddsa_pk_from_ptr(eddsa_pk_t *pk, const void *ptr, size_t len);

EVP_PKEY *
eddsa_pk_to_EVP_PKEY(const eddsa_pk_t *pk);

DESCRIPTION¶

EDDSA is the name given in the CBOR Object Signing and Encryption (COSE) RFC to EDDSA over Curve25519 with SHA-512. The COSE EDDSA API of libfido2 is an auxiliary API with routines to convert between the different EDDSA public key types used in libfido2 and OpenSSL.

In libfido2, EDDSA public keys are abstracted by the eddsa_pk_t type.

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

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

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

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

The eddsa_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, eddsa_pk_to_EVP_PKEY() returns NULL.

RETURN VALUES¶

The eddsa_pk_from_EVP_PKEY() and eddsa_pk_from_ptr() functions return FIDO_OK on success. On error, a different error code defined in <fido/err.h> is returned.

SEE ALSO¶

es256_pk_new(3), es384_pk_new(3), fido_assert_verify(3), fido_cred_pubkey_ptr(3), rs256_pk_new(3)