1.\" Copyright (c) 2018-2022 Yubico AB. All rights reserved. 2.\" 3.\" Redistribution and use in source and binary forms, with or without 4.\" modification, are permitted provided that the following conditions are 5.\" met: 6.\" 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in 11.\" the documentation and/or other materials provided with the 12.\" distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 15.\" "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 16.\" LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 17.\" A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 18.\" HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 19.\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 20.\" LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 24.\" OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25.\" 26.\" SPDX-License-Identifier: BSD-2-Clause 27.\" 28.Dd $Mdocdate: July 15 2022 $ 29.Dt RS256_PK_NEW 3 30.Os 31.Sh NAME 32.Nm rs256_pk_new , 33.Nm rs256_pk_free , 34.Nm rs256_pk_from_RSA , 35.Nm rs256_pk_from_EVP_PKEY , 36.Nm rs256_pk_from_ptr , 37.Nm rs256_pk_to_EVP_PKEY 38.Nd FIDO2 COSE RS256 API 39.Sh SYNOPSIS 40.In openssl/rsa.h 41.In fido/rs256.h 42.Ft rs256_pk_t * 43.Fn rs256_pk_new "void" 44.Ft void 45.Fn rs256_pk_free "rs256_pk_t **pkp" 46.Ft int 47.Fn rs256_pk_from_EVP_PKEY "rs256_pk_t *pk" "const EVP_PKEY *pkey" 48.Ft int 49.Fn rs256_pk_from_RSA "rs256_pk_t *pk" "const RSA *rsa" 50.Ft int 51.Fn rs256_pk_from_ptr "rs256_pk_t *pk" "const void *ptr" "size_t len" 52.Ft EVP_PKEY * 53.Fn rs256_pk_to_EVP_PKEY "const rs256_pk_t *pk" 54.Sh DESCRIPTION 55RS256 is the name given in the CBOR Object Signing and Encryption 56(COSE) RFC to PKCS#1.5 2048-bit RSA with SHA-256. 57The COSE RS256 API of 58.Em libfido2 59is an auxiliary API with routines to convert between the different 60RSA public key types used in 61.Em libfido2 62and 63.Em OpenSSL . 64.Pp 65In 66.Em libfido2 , 67RS256 public keys are abstracted by the 68.Vt rs256_pk_t 69type. 70.Pp 71The 72.Fn rs256_pk_new 73function returns a pointer to a newly allocated, empty 74.Vt rs256_pk_t 75type. 76If memory cannot be allocated, NULL is returned. 77.Pp 78The 79.Fn rs256_pk_free 80function releases the memory backing 81.Fa *pkp , 82where 83.Fa *pkp 84must have been previously allocated by 85.Fn rs256_pk_new . 86On return, 87.Fa *pkp 88is set to NULL. 89Either 90.Fa pkp 91or 92.Fa *pkp 93may be NULL, in which case 94.Fn rs256_pk_free 95is a NOP. 96.Pp 97The 98.Fn rs256_pk_from_EVP_PKEY 99function fills 100.Fa pk 101with the contents of 102.Fa pkey . 103No references to 104.Fa pkey 105are kept. 106.Pp 107The 108.Fn rs256_pk_from_RSA 109function fills 110.Fa pk 111with the contents of 112.Fa rsa . 113No references to 114.Fa rsa 115are kept. 116.Pp 117The 118.Fn rs256_pk_from_ptr 119function fills 120.Fa pk 121with the contents of 122.Fa ptr , 123where 124.Fa ptr 125points to 126.Fa len 127bytes. 128No references to 129.Fa ptr 130are kept. 131.Pp 132The 133.Fn rs256_pk_to_EVP_PKEY 134function converts 135.Fa pk 136to a newly allocated 137.Fa EVP_PKEY 138type with a reference count of 1. 139No internal references to the returned pointer are kept. 140If an error occurs, 141.Fn rs256_pk_to_EVP_PKEY 142returns NULL. 143.Sh RETURN VALUES 144The 145.Fn rs256_pk_from_EVP_PKEY , 146.Fn rs256_pk_from_RSA , 147and 148.Fn rs256_pk_from_ptr 149functions return 150.Dv FIDO_OK 151on success. 152On error, a different error code defined in 153.In fido/err.h 154is returned. 155.Sh SEE ALSO 156.Xr eddsa_pk_new 3 , 157.Xr es256_pk_new 3 , 158.Xr es384_pk_new 3 , 159.Xr fido_assert_verify 3 , 160.Xr fido_cred_pubkey_ptr 3 161