include/openssl/hpke.h

   1 /*
   2  * Copyright 2022-2023 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 /* APIs and data structures for HPKE (RFC9180)  */
  11 #ifndef OSSL_HPKE_H
  12 # define OSSL_HPKE_H
  13 # pragma once
  14
  15 # include <openssl/types.h>
  16
  17 /* HPKE modes */
  18 # define OSSL_HPKE_MODE_BASE              0 /* Base mode  */
  19 # define OSSL_HPKE_MODE_PSK               1 /* Pre-shared key mode */
  20 # define OSSL_HPKE_MODE_AUTH              2 /* Authenticated mode */
  21 # define OSSL_HPKE_MODE_PSKAUTH           3 /* PSK+authenticated mode */
  22
  23 /*
  24  * Max for ikm, psk, pskid, info and exporter contexts.
  25  * RFC9180, section 7.2.1 RECOMMENDS 64 octets but we have test vectors from
  26  * Appendix A.6.1 with a 66 octet IKM so we'll allow that.
  27  */
  28 # define OSSL_HPKE_MAX_PARMLEN        66
  29 # define OSSL_HPKE_MIN_PSKLEN         32
  30 # define OSSL_HPKE_MAX_INFOLEN        1024
  31
  32 /*
  33  * The (16bit) HPKE algorithm ID IANA codepoints
  34  * If/when new IANA codepoints are added there are tables in
  35  * crypto/hpke/hpke_util.c that must also be updated.
  36  */
  37 # define OSSL_HPKE_KEM_ID_RESERVED         0x0000 /* not used */
  38 # define OSSL_HPKE_KEM_ID_P256             0x0010 /* NIST P-256 */
  39 # define OSSL_HPKE_KEM_ID_P384             0x0011 /* NIST P-384 */
  40 # define OSSL_HPKE_KEM_ID_P521             0x0012 /* NIST P-521 */
  41 # define OSSL_HPKE_KEM_ID_X25519           0x0020 /* Curve25519 */
  42 # define OSSL_HPKE_KEM_ID_X448             0x0021 /* Curve448 */
  43
  44 # define OSSL_HPKE_KDF_ID_RESERVED         0x0000 /* not used */
  45 # define OSSL_HPKE_KDF_ID_HKDF_SHA256      0x0001 /* HKDF-SHA256 */
  46 # define OSSL_HPKE_KDF_ID_HKDF_SHA384      0x0002 /* HKDF-SHA384 */
  47 # define OSSL_HPKE_KDF_ID_HKDF_SHA512      0x0003 /* HKDF-SHA512 */
  48
  49 # define OSSL_HPKE_AEAD_ID_RESERVED        0x0000 /* not used */
  50 # define OSSL_HPKE_AEAD_ID_AES_GCM_128     0x0001 /* AES-GCM-128 */
  51 # define OSSL_HPKE_AEAD_ID_AES_GCM_256     0x0002 /* AES-GCM-256 */
  52 # define OSSL_HPKE_AEAD_ID_CHACHA_POLY1305 0x0003 /* Chacha20-Poly1305 */
  53 # define OSSL_HPKE_AEAD_ID_EXPORTONLY      0xFFFF /* export-only fake ID */
  54
  55 /* strings for suite components */
  56 # define OSSL_HPKE_KEMSTR_P256        "P-256"              /* KEM id 0x10 */
  57 # define OSSL_HPKE_KEMSTR_P384        "P-384"              /* KEM id 0x11 */
  58 # define OSSL_HPKE_KEMSTR_P521        "P-521"              /* KEM id 0x12 */
  59 # define OSSL_HPKE_KEMSTR_X25519      "X25519"             /* KEM id 0x20 */
  60 # define OSSL_HPKE_KEMSTR_X448        "X448"               /* KEM id 0x21 */
  61 # define OSSL_HPKE_KDFSTR_256         "hkdf-sha256"        /* KDF id 1 */
  62 # define OSSL_HPKE_KDFSTR_384         "hkdf-sha384"        /* KDF id 2 */
  63 # define OSSL_HPKE_KDFSTR_512         "hkdf-sha512"        /* KDF id 3 */
  64 # define OSSL_HPKE_AEADSTR_AES128GCM  "aes-128-gcm"        /* AEAD id 1 */
  65 # define OSSL_HPKE_AEADSTR_AES256GCM  "aes-256-gcm"        /* AEAD id 2 */
  66 # define OSSL_HPKE_AEADSTR_CP         "chacha20-poly1305"  /* AEAD id 3 */
  67 # define OSSL_HPKE_AEADSTR_EXP        "exporter"           /* AEAD id 0xff */
  68
  69 /*
  70  * Roles for use in creating an OSSL_HPKE_CTX, most
  71  * important use of this is to control nonce reuse.
  72  */
  73 # define OSSL_HPKE_ROLE_SENDER 0
  74 # define OSSL_HPKE_ROLE_RECEIVER 1
  75
  76 # ifdef  __cplusplus
  77 extern "C" {
  78 # endif
  79
  80 typedef struct {
  81     uint16_t    kem_id; /* Key Encapsulation Method id */
  82     uint16_t    kdf_id; /* Key Derivation Function id */
  83     uint16_t    aead_id; /* AEAD alg id */
  84 } OSSL_HPKE_SUITE;
  85
  86 /**
  87  * Suite constants, use this like:
  88  *          OSSL_HPKE_SUITE myvar = OSSL_HPKE_SUITE_DEFAULT;
  89  */
  90 # ifndef OPENSSL_NO_ECX
  91 #  define OSSL_HPKE_SUITE_DEFAULT \
  92     {\
  93         OSSL_HPKE_KEM_ID_X25519, \
  94         OSSL_HPKE_KDF_ID_HKDF_SHA256, \
  95         OSSL_HPKE_AEAD_ID_AES_GCM_128 \
  96     }
  97 # else
  98 #  define OSSL_HPKE_SUITE_DEFAULT \
  99     {\
 100         OSSL_HPKE_KEM_ID_P256, \
 101         OSSL_HPKE_KDF_ID_HKDF_SHA256, \
 102         OSSL_HPKE_AEAD_ID_AES_GCM_128 \
 103     }
 104 #endif
 105
 106 typedef struct ossl_hpke_ctx_st OSSL_HPKE_CTX;
 107
 108 OSSL_HPKE_CTX *OSSL_HPKE_CTX_new(int mode, OSSL_HPKE_SUITE suite, int role,
 109                                  OSSL_LIB_CTX *libctx, const char *propq);
 110 void OSSL_HPKE_CTX_free(OSSL_HPKE_CTX *ctx);
 111
 112 int OSSL_HPKE_encap(OSSL_HPKE_CTX *ctx,
 113                     unsigned char *enc, size_t *enclen,
 114                     const unsigned char *pub, size_t publen,
 115                     const unsigned char *info, size_t infolen);
 116 int OSSL_HPKE_seal(OSSL_HPKE_CTX *ctx,
 117                    unsigned char *ct, size_t *ctlen,
 118                    const unsigned char *aad, size_t aadlen,
 119                    const unsigned char *pt, size_t ptlen);
 120
 121 int OSSL_HPKE_keygen(OSSL_HPKE_SUITE suite,
 122                      unsigned char *pub, size_t *publen, EVP_PKEY **priv,
 123                      const unsigned char *ikm, size_t ikmlen,
 124                      OSSL_LIB_CTX *libctx, const char *propq);
 125 int OSSL_HPKE_decap(OSSL_HPKE_CTX *ctx,
 126                     const unsigned char *enc, size_t enclen,
 127                     EVP_PKEY *recippriv,
 128                     const unsigned char *info, size_t infolen);
 129 int OSSL_HPKE_open(OSSL_HPKE_CTX *ctx,
 130                    unsigned char *pt, size_t *ptlen,
 131                    const unsigned char *aad, size_t aadlen,
 132                    const unsigned char *ct, size_t ctlen);
 133
 134 int OSSL_HPKE_export(OSSL_HPKE_CTX *ctx,
 135                      unsigned char *secret,
 136                      size_t secretlen,
 137                      const unsigned char *label,
 138                      size_t labellen);
 139
 140 int OSSL_HPKE_CTX_set1_authpriv(OSSL_HPKE_CTX *ctx, EVP_PKEY *priv);
 141 int OSSL_HPKE_CTX_set1_authpub(OSSL_HPKE_CTX *ctx,
 142                                const unsigned char *pub,
 143                                size_t publen);
 144 int OSSL_HPKE_CTX_set1_psk(OSSL_HPKE_CTX *ctx,
 145                            const char *pskid,
 146                            const unsigned char *psk, size_t psklen);
 147
 148 int OSSL_HPKE_CTX_set1_ikme(OSSL_HPKE_CTX *ctx,
 149                             const unsigned char *ikme, size_t ikmelen);
 150
 151 int OSSL_HPKE_CTX_set_seq(OSSL_HPKE_CTX *ctx, uint64_t seq);
 152 int OSSL_HPKE_CTX_get_seq(OSSL_HPKE_CTX *ctx, uint64_t *seq);
 153
 154 int OSSL_HPKE_suite_check(OSSL_HPKE_SUITE suite);
 155 int OSSL_HPKE_get_grease_value(const OSSL_HPKE_SUITE *suite_in,
 156                                OSSL_HPKE_SUITE *suite,
 157                                unsigned char *enc, size_t *enclen,
 158                                unsigned char *ct, size_t ctlen,
 159                                OSSL_LIB_CTX *libctx, const char *propq);
 160 int OSSL_HPKE_str2suite(const char *str, OSSL_HPKE_SUITE *suite);
 161 size_t OSSL_HPKE_get_ciphertext_size(OSSL_HPKE_SUITE suite, size_t clearlen);
 162 size_t OSSL_HPKE_get_public_encap_size(OSSL_HPKE_SUITE suite);
 163 size_t OSSL_HPKE_get_recommended_ikmelen(OSSL_HPKE_SUITE suite);
 164
 165 # ifdef  __cplusplus
 166 }
 167 # endif
 168
 169 #endif