xref: /aosp_15_r20/external/boringssl/src/crypto/kyber/internal.h (revision 8fb009dc861624b67b6cdb62ea21f0f22d0c584b)
1 /* Copyright (c) 2023, Google Inc.
2  *
3  * Permission to use, copy, modify, and/or distribute this software for any
4  * purpose with or without fee is hereby granted, provided that the above
5  * copyright notice and this permission notice appear in all copies.
6  *
7  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
8  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
9  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
10  * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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13  * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
14 
15 #ifndef OPENSSL_HEADER_CRYPTO_KYBER_INTERNAL_H
16 #define OPENSSL_HEADER_CRYPTO_KYBER_INTERNAL_H
17 
18 #include <openssl/base.h>
19 #include <openssl/experimental/kyber.h>
20 
21 #if defined(__cplusplus)
22 extern "C" {
23 #endif
24 
25 
26 // KYBER_ENCAP_ENTROPY is the number of bytes of uniformly random entropy
27 // necessary to encapsulate a secret. The entropy will be leaked to the
28 // decapsulating party.
29 #define KYBER_ENCAP_ENTROPY 32
30 
31 // KYBER_GENERATE_KEY_ENTROPY is the number of bytes of uniformly random entropy
32 // necessary to generate a key.
33 #define KYBER_GENERATE_KEY_ENTROPY 64
34 
35 // KYBER_generate_key_external_entropy is a deterministic function to create a
36 // pair of Kyber768 keys, using the supplied entropy. The entropy needs to be
37 // uniformly random generated. This function is should only be used for tests,
38 // regular callers should use the non-deterministic |KYBER_generate_key|
39 // directly.
40 OPENSSL_EXPORT void KYBER_generate_key_external_entropy(
41     uint8_t out_encoded_public_key[KYBER_PUBLIC_KEY_BYTES],
42     struct KYBER_private_key *out_private_key,
43     const uint8_t entropy[KYBER_GENERATE_KEY_ENTROPY]);
44 
45 // KYBER_encap_external_entropy behaves like |KYBER_encap|, but uses
46 // |KYBER_ENCAP_ENTROPY| bytes of |entropy| for randomization. The decapsulating
47 // side will be able to recover |entropy| in full. This function should only be
48 // used for tests, regular callers should use the non-deterministic
49 // |KYBER_encap| directly.
50 OPENSSL_EXPORT void KYBER_encap_external_entropy(
51     uint8_t out_ciphertext[KYBER_CIPHERTEXT_BYTES],
52     uint8_t out_shared_secret[KYBER_SHARED_SECRET_BYTES],
53     const struct KYBER_public_key *public_key,
54     const uint8_t entropy[KYBER_ENCAP_ENTROPY]);
55 
56 #if defined(__cplusplus)
57 }
58 #endif
59 
60 #endif  // OPENSSL_HEADER_CRYPTO_KYBER_INTERNAL_H
61