1ES256_PK_NEW(3)          BSD Library Functions Manual          ES256_PK_NEW(3)
2

NAME

4     es256_pk_new, es256_pk_free, es256_pk_from_EC_KEY, es256_pk_from_ptr,
5     es256_pk_to_EVP_PKEY — FIDO 2 COSE ES256 API
6

SYNOPSIS

8     #include <openssl/ec.h>
9     #include <fido/es256.h>
10
11     es256_pk_t *
12     es256_pk_new(void);
13
14     void
15     es256_pk_free(es256_pk_t **pkp);
16
17     int
18     es256_pk_from_EC_KEY(es256_pk_t *pk, const EC_KEY *ec);
19
20     int
21     es256_pk_from_ptr(es256_pk_t *pk, const void *ptr, size_t len);
22
23     EVP_PKEY *
24     es256_pk_to_EVP_PKEY(const es256_pk_t *pk);
25

DESCRIPTION

27     ES256 is the name given in the CBOR Object Signing and Encryption (COSE)
28     RFC to ECDSA over P-256 with SHA-256.  The COSE ES256 API of libfido2 is
29     an auxiliary API with routines to convert between the different ECDSA
30     public key types used in libfido2 and OpenSSL.
31
32     In libfido2, ES256 public keys are abstracted by the es256_pk_t type.
33
34     The es256_pk_new() function returns a pointer to a newly allocated, empty
35     es256_pk_t type.  If memory cannot be allocated, NULL is returned.
36
37     The es256_pk_free() function releases the memory backing *pkp, where *pkp
38     must have been previously allocated by es256_pk_new().  On return, *pkp
39     is set to NULL.  Either pkp or *pkp may be NULL, in which case
40     es256_pk_free() is a NOP.
41
42     The es256_pk_from_EC_KEY() function fills pk with the contents of ec.  No
43     references to ec are kept.
44
45     The es256_pk_from_ptr() function fills pk with the contents of ptr, where
46     ptr points to len bytes.  No references to ptr are kept.
47
48     The es256_pk_to_EVP_PKEY() function converts pk to a newly allocated
49     EVP_PKEY type with a reference count of 1.  No internal references to the
50     returned pointer are kept.  If an error occurs, es256_pk_to_EVP_PKEY()
51     returns NULL.
52

RETURN VALUES

54     The es256_pk_from_EC_KEY() and es256_pk_from_ptr() functions return
55     FIDO_OK on success.  On error, a different error code defined in
56     <fido/err.h> is returned.
57

SEE ALSO

59     eddsa_pk_new(3), fido_assert_verify(3), fido_cred_pubkey_ptr(3),
60     rs256_pk_new(3)
61
62BSD                              May 10, 2020                              BSD
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