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)

Debian                                            July 15, 2022                                  EDDSA_PK_NEW(3)