include/openssl/hpke.h

0001 /*
0002  * Copyright 2022-2024 The OpenSSL Project Authors. All Rights Reserved.
0003  *
0004  * Licensed under the Apache License 2.0 (the "License").  You may not use
0005  * this file except in compliance with the License.  You can obtain a copy
0006  * in the file LICENSE in the source distribution or at
0007  * https://www.openssl.org/source/license.html
0008  */
0009
0010 /* APIs and data structures for HPKE (RFC9180)  */
0011 #ifndef OSSL_HPKE_H
0012 #define OSSL_HPKE_H
0013 #pragma once
0014
0015 #include <openssl/types.h>
0016
0017 /* HPKE modes */
0018 #define OSSL_HPKE_MODE_BASE 0 /* Base mode  */
0019 #define OSSL_HPKE_MODE_PSK 1 /* Pre-shared key mode */
0020 #define OSSL_HPKE_MODE_AUTH 2 /* Authenticated mode */
0021 #define OSSL_HPKE_MODE_PSKAUTH 3 /* PSK+authenticated mode */
0022
0023 /*
0024  * Max for ikm, psk, pskid, info and exporter contexts.
0025  * RFC9180, section 7.2.1 RECOMMENDS 64 octets but we have test vectors from
0026  * Appendix A.6.1 with a 66 octet IKM so we'll allow that.
0027  */
0028 #define OSSL_HPKE_MAX_PARMLEN 66
0029 #define OSSL_HPKE_MIN_PSKLEN 32
0030 #define OSSL_HPKE_MAX_INFOLEN 1024
0031
0032 /*
0033  * The (16bit) HPKE algorithm ID IANA codepoints
0034  * If/when new IANA codepoints are added there are tables in
0035  * crypto/hpke/hpke_util.c that must also be updated.
0036  */
0037 #define OSSL_HPKE_KEM_ID_RESERVED 0x0000 /* not used */
0038 #define OSSL_HPKE_KEM_ID_P256 0x0010 /* NIST P-256 */
0039 #define OSSL_HPKE_KEM_ID_P384 0x0011 /* NIST P-384 */
0040 #define OSSL_HPKE_KEM_ID_P521 0x0012 /* NIST P-521 */
0041 #define OSSL_HPKE_KEM_ID_X25519 0x0020 /* Curve25519 */
0042 #define OSSL_HPKE_KEM_ID_X448 0x0021 /* Curve448 */
0043
0044 #define OSSL_HPKE_KDF_ID_RESERVED 0x0000 /* not used */
0045 #define OSSL_HPKE_KDF_ID_HKDF_SHA256 0x0001 /* HKDF-SHA256 */
0046 #define OSSL_HPKE_KDF_ID_HKDF_SHA384 0x0002 /* HKDF-SHA384 */
0047 #define OSSL_HPKE_KDF_ID_HKDF_SHA512 0x0003 /* HKDF-SHA512 */
0048
0049 #define OSSL_HPKE_AEAD_ID_RESERVED 0x0000 /* not used */
0050 #define OSSL_HPKE_AEAD_ID_AES_GCM_128 0x0001 /* AES-GCM-128 */
0051 #define OSSL_HPKE_AEAD_ID_AES_GCM_256 0x0002 /* AES-GCM-256 */
0052 #define OSSL_HPKE_AEAD_ID_CHACHA_POLY1305 0x0003 /* Chacha20-Poly1305 */
0053 #define OSSL_HPKE_AEAD_ID_EXPORTONLY 0xFFFF /* export-only fake ID */
0054
0055 /* strings for suite components */
0056 #define OSSL_HPKE_KEMSTR_P256 "P-256" /* KEM id 0x10 */
0057 #define OSSL_HPKE_KEMSTR_P384 "P-384" /* KEM id 0x11 */
0058 #define OSSL_HPKE_KEMSTR_P521 "P-521" /* KEM id 0x12 */
0059 #define OSSL_HPKE_KEMSTR_X25519 "X25519" /* KEM id 0x20 */
0060 #define OSSL_HPKE_KEMSTR_X448 "X448" /* KEM id 0x21 */
0061 #define OSSL_HPKE_KDFSTR_256 "hkdf-sha256" /* KDF id 1 */
0062 #define OSSL_HPKE_KDFSTR_384 "hkdf-sha384" /* KDF id 2 */
0063 #define OSSL_HPKE_KDFSTR_512 "hkdf-sha512" /* KDF id 3 */
0064 #define OSSL_HPKE_AEADSTR_AES128GCM "aes-128-gcm" /* AEAD id 1 */
0065 #define OSSL_HPKE_AEADSTR_AES256GCM "aes-256-gcm" /* AEAD id 2 */
0066 #define OSSL_HPKE_AEADSTR_CP "chacha20-poly1305" /* AEAD id 3 */
0067 #define OSSL_HPKE_AEADSTR_EXP "exporter" /* AEAD id 0xff */
0068
0069 /*
0070  * Roles for use in creating an OSSL_HPKE_CTX, most
0071  * important use of this is to control nonce reuse.
0072  */
0073 #define OSSL_HPKE_ROLE_SENDER 0
0074 #define OSSL_HPKE_ROLE_RECEIVER 1
0075
0076 #ifdef __cplusplus
0077 extern "C" {
0078 #endif
0079
0080 typedef struct {
0081     uint16_t kem_id; /* Key Encapsulation Method id */
0082     uint16_t kdf_id; /* Key Derivation Function id */
0083     uint16_t aead_id; /* AEAD alg id */
0084 } OSSL_HPKE_SUITE;
0085
0086 /**
0087  * Suite constants, use this like:
0088  *          OSSL_HPKE_SUITE myvar = OSSL_HPKE_SUITE_DEFAULT;
0089  */
0090 #ifndef OPENSSL_NO_ECX
0091 #define OSSL_HPKE_SUITE_DEFAULT       \
0092     {                                 \
0093         OSSL_HPKE_KEM_ID_X25519,      \
0094         OSSL_HPKE_KDF_ID_HKDF_SHA256, \
0095         OSSL_HPKE_AEAD_ID_AES_GCM_128 \
0096     }
0097 #else
0098 #define OSSL_HPKE_SUITE_DEFAULT       \
0099     {                                 \
0100         OSSL_HPKE_KEM_ID_P256,        \
0101         OSSL_HPKE_KDF_ID_HKDF_SHA256, \
0102         OSSL_HPKE_AEAD_ID_AES_GCM_128 \
0103     }
0104 #endif
0105
0106 typedef struct ossl_hpke_ctx_st OSSL_HPKE_CTX;
0107
0108 OSSL_HPKE_CTX *OSSL_HPKE_CTX_new(int mode, OSSL_HPKE_SUITE suite, int role,
0109     OSSL_LIB_CTX *libctx, const char *propq);
0110 void OSSL_HPKE_CTX_free(OSSL_HPKE_CTX *ctx);
0111
0112 int OSSL_HPKE_encap(OSSL_HPKE_CTX *ctx,
0113     unsigned char *enc, size_t *enclen,
0114     const unsigned char *pub, size_t publen,
0115     const unsigned char *info, size_t infolen);
0116 int OSSL_HPKE_seal(OSSL_HPKE_CTX *ctx,
0117     unsigned char *ct, size_t *ctlen,
0118     const unsigned char *aad, size_t aadlen,
0119     const unsigned char *pt, size_t ptlen);
0120
0121 int OSSL_HPKE_keygen(OSSL_HPKE_SUITE suite,
0122     unsigned char *pub, size_t *publen, EVP_PKEY **priv,
0123     const unsigned char *ikm, size_t ikmlen,
0124     OSSL_LIB_CTX *libctx, const char *propq);
0125 int OSSL_HPKE_decap(OSSL_HPKE_CTX *ctx,
0126     const unsigned char *enc, size_t enclen,
0127     EVP_PKEY *recippriv,
0128     const unsigned char *info, size_t infolen);
0129 int OSSL_HPKE_open(OSSL_HPKE_CTX *ctx,
0130     unsigned char *pt, size_t *ptlen,
0131     const unsigned char *aad, size_t aadlen,
0132     const unsigned char *ct, size_t ctlen);
0133
0134 int OSSL_HPKE_export(OSSL_HPKE_CTX *ctx,
0135     unsigned char *secret,
0136     size_t secretlen,
0137     const unsigned char *label,
0138     size_t labellen);
0139
0140 int OSSL_HPKE_CTX_set1_authpriv(OSSL_HPKE_CTX *ctx, EVP_PKEY *priv);
0141 int OSSL_HPKE_CTX_set1_authpub(OSSL_HPKE_CTX *ctx,
0142     const unsigned char *pub,
0143     size_t publen);
0144 int OSSL_HPKE_CTX_set1_psk(OSSL_HPKE_CTX *ctx,
0145     const char *pskid,
0146     const unsigned char *psk, size_t psklen);
0147
0148 int OSSL_HPKE_CTX_set1_ikme(OSSL_HPKE_CTX *ctx,
0149     const unsigned char *ikme, size_t ikmelen);
0150
0151 int OSSL_HPKE_CTX_set_seq(OSSL_HPKE_CTX *ctx, uint64_t seq);
0152 int OSSL_HPKE_CTX_get_seq(OSSL_HPKE_CTX *ctx, uint64_t *seq);
0153
0154 int OSSL_HPKE_suite_check(OSSL_HPKE_SUITE suite);
0155 int OSSL_HPKE_get_grease_value(const OSSL_HPKE_SUITE *suite_in,
0156     OSSL_HPKE_SUITE *suite,
0157     unsigned char *enc, size_t *enclen,
0158     unsigned char *ct, size_t ctlen,
0159     OSSL_LIB_CTX *libctx, const char *propq);
0160 int OSSL_HPKE_str2suite(const char *str, OSSL_HPKE_SUITE *suite);
0161 size_t OSSL_HPKE_get_ciphertext_size(OSSL_HPKE_SUITE suite, size_t clearlen);
0162 size_t OSSL_HPKE_get_public_encap_size(OSSL_HPKE_SUITE suite);
0163 size_t OSSL_HPKE_get_recommended_ikmelen(OSSL_HPKE_SUITE suite);
0164
0165 #ifdef __cplusplus
0166 }
0167 #endif
0168
0169 #endif