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      1 /*
      2  * Copyright 2025 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 #ifndef PROV_ML_COMMON_CODECS_H
     11 #define PROV_ML_COMMON_CODECS_H
     12 #pragma once
     13 
     14 #include <openssl/e_os2.h>
     15 #include "crypto/ml_dsa.h"
     16 #include "prov/provider_ctx.h"
     17 
     18 /*-
     19  * The DER ASN.1 encoding of ML-DSA and ML-KEM public keys prepends 22 bytes
     20  * to the encoded public key:
     21  *
     22  * - 4 byte outer sequence tag and length
     23  * -  2 byte algorithm sequence tag and length
     24  * -    2 byte algorithm OID tag and length
     25  * -      9 byte algorithm OID (from NIST CSOR OID arc)
     26  * -  4 byte bit string tag and length
     27  * -    1 bitstring lead byte
     28  */
     29 #define ML_COMMON_SPKI_OVERHEAD 22
     30 typedef struct {
     31     const uint8_t asn1_prefix[ML_COMMON_SPKI_OVERHEAD];
     32 } ML_COMMON_SPKI_FMT;
     33 
     34 /*-
     35  * For each parameter set we support a few PKCS#8 input formats, three
     36  * corresponding to the "either or both" variants of:
     37  *
     38  *  ML-DSA-PrivateKey ::= CHOICE {
     39  *    seed [0] IMPLICIT OCTET STRING (SIZE (32)),
     40  *    expandedKey OCTET STRING (SIZE (2560 | 4032 | 4896)),
     41  *    both SEQUENCE {
     42  *      seed OCTET STRING (SIZE (32)),
     43  *      expandedKey OCTET STRING (SIZE (2560 | 4032 | 4896)) } }
     44  *
     45  *  ML-KEM-PrivateKey ::= CHOICE {
     46  *    seed [0] IMPLICIT OCTET STRING (SIZE (64)),
     47  *    expandedKey OCTET STRING (SIZE (1632 | 2400 | 3168)),
     48  *    both SEQUENCE {
     49  *      seed OCTET STRING (SIZE (64)),
     50  *      expandedKey OCTET STRING SIZE ((1632 | 2400 | 3168)) } }
     51  *
     52  * one more for a historical OQS encoding:
     53  *
     54  * - OQS private + public key: OCTET STRING
     55  *   (The public key is ignored, just as with PKCS#8 v2.)
     56  *
     57  * and two more that are the minimal IETF non-ASN.1 seed encoding:
     58  *
     59  * - Bare seed (just the 32 or 64 bytes)
     60  * - Bare priv (just the key bytes)
     61  *
     62  * A length of zero means that particular field is absent.
     63  *
     64  * The p8_shift is 0 when the top-level tag+length occupy four bytes, 2 when
     65  * they occupy two byes, and 4 when no tag is used at all.
     66  */
     67 #define NUM_PKCS8_FORMATS 6
     68 
     69 typedef struct {
     70     const char *p8_name; /* Format name */
     71     size_t p8_bytes; /* Total P8 encoding length */
     72     int p8_shift; /* 4 - (top-level tag + len) */
     73     uint32_t p8_magic; /* The tag + len value */
     74     uint16_t seed_magic; /* Interior tag + len for the seed */
     75     size_t seed_offset; /* Seed offset from start */
     76     size_t seed_length; /* Seed bytes */
     77     uint32_t priv_magic; /* Interior tag + len for the key */
     78     size_t priv_offset; /* Key offset from start */
     79     size_t priv_length; /* Key bytes */
     80     size_t pub_offset; /* Pubkey offset */
     81     size_t pub_length; /* Pubkey bytes */
     82 } ML_COMMON_PKCS8_FMT;
     83 
     84 typedef struct {
     85     const ML_COMMON_SPKI_FMT *spkifmt;
     86     const ML_COMMON_PKCS8_FMT *p8fmt;
     87 } ML_COMMON_CODEC;
     88 
     89 typedef struct {
     90     const ML_COMMON_PKCS8_FMT *fmt;
     91     int pref;
     92 } ML_COMMON_PKCS8_FMT_PREF;
     93 
     94 ML_COMMON_PKCS8_FMT_PREF *
     95 ossl_ml_common_pkcs8_fmt_order(const char *algorithm_name,
     96     const ML_COMMON_PKCS8_FMT *p8fmt,
     97     const char *direction, const char *formats);
     98 #endif
     99