1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
|
.\" Copyright (c) 2018 Yubico AB. All rights reserved.
.\" Use of this source code is governed by a BSD-style
.\" license that can be found in the LICENSE file.
.\"
.Dd $Mdocdate: May 24 2018 $
.Dt ES256_PK_NEW 3
.Os
.Sh NAME
.Nm es256_pk_new ,
.Nm es256_pk_free ,
.Nm es256_pk_from_EC_KEY ,
.Nm es256_pk_from_ptr ,
.Nm es256_pk_to_EVP_PKEY
.Nd FIDO 2 COSE ES256 API
.Sh SYNOPSIS
.In openssl/ec.h
.In fido/es256.h
.Ft es256_pk_t *
.Fn es256_pk_new "void"
.Ft void
.Fn es256_pk_free "es256_pk_t **pkp"
.Ft int
.Fn es256_pk_from_EC_KEY "es256_pk_t *pk" "const EC_KEY *ec"
.Ft int
.Fn es256_pk_from_ptr "es256_pk_t *pk" "const void *ptr" "size_t len"
.Ft EVP_PKEY *
.Fn es256_pk_to_EVP_PKEY "const es256_pk_t *pk"
.Sh DESCRIPTION
ES256 is the name given in the CBOR Object Signing and Encryption
(COSE) RFC to ECDSA over P-256 with SHA-256.
The COSE ES256 API of
.Em libfido2
is an auxiliary API with routines to convert between the different
ECDSA public key types used in
.Em libfido2
and
.Em OpenSSL .
.Pp
In
.Em libfido2 ,
ES256 public keys are abstracted by the
.Vt es256_pk_t
type.
.Pp
The
.Fn es256_pk_new
function returns a pointer to a newly allocated, empty
.Vt es256_pk_t
type.
If memory cannot be allocated, NULL is returned.
.Pp
The
.Fn es256_pk_free
function releases the memory backing
.Fa *pkp ,
where
.Fa *pkp
must have been previously allocated by
.Fn es256_pk_new .
On return,
.Fa *pkp
is set to NULL.
Either
.Fa pkp
or
.Fa *pkp
may be NULL, in which case
.Fn es256_pk_free
is a NOP.
.Pp
The
.Fn es256_pk_from_EC_KEY
function fills
.Fa pk
with the contents of
.Fa ec .
No references to
.Fa ec
are kept.
.Pp
The
.Fn es256_pk_from_ptr
function fills
.Fa pk
with the contents of
.Fa ptr ,
where
.Fa ptr
points to
.Fa len
bytes.
The
.Fa ptr
pointer may point to an uncompressed point, or to the
concatenation of the x and y coordinates.
No references to
.Fa ptr
are kept.
.Pp
The
.Fn es256_pk_to_EVP_PKEY
function converts
.Fa pk
to a newly allocated
.Fa EVP_PKEY
type with a reference count of 1.
No internal references to the returned pointer are kept.
If an error occurs,
.Fn es256_pk_to_EVP_PKEY
returns NULL.
.Sh RETURN VALUES
The
.Fn es256_pk_from_EC_KEY
and
.Fn es256_pk_from_ptr
functions return
.Dv FIDO_OK
on success.
On error, a different error code defined in
.In fido/err.h
is returned.
.Sh SEE ALSO
.Xr eddsa_pk_new 3 ,
.Xr fido_assert_verify 3 ,
.Xr fido_cred_pubkey_ptr 3 ,
.Xr rs256_pk_new 3
|
