mirror of
https://github.com/henrydcase/pqc.git
synced 2024-11-23 16:08:59 +00:00
29 lines
1.1 KiB
C
29 lines
1.1 KiB
C
#ifndef SPX_HASH_STATE_H
|
||
#define SPX_HASH_STATE_H
|
||
|
||
/**
|
||
* Defines the type of the hash function state.
|
||
*
|
||
* Don't be fooled into thinking this instance of SPHINCS+ isn't stateless!
|
||
*
|
||
* From Section 7.2.2 from the SPHINCS+ round-2 specification:
|
||
*
|
||
* Each of the instances of the tweakable hash function take PK.seed as its
|
||
* first input, which is constant for a given key pair – and, thus, across
|
||
* a single signature. This leads to a lot of redundant computation. To remedy
|
||
* this, we pad PK.seed to the length of a full 64-byte SHA-256 input block.
|
||
* Because of the Merkle-Damgård construction that underlies SHA-256, this
|
||
* allows for reuse of the intermediate SHA-256 state after the initial call to
|
||
* the compression function which improves performance.
|
||
*
|
||
* SHAKE256 does not need this state. Because this implementation is generated
|
||
* from a shared code base, we still need to specify some hash_state as it is
|
||
* still passed around. We chose to use an `int` as a placeholder for this
|
||
* purpose.
|
||
*/
|
||
|
||
#include "sha2.h"
|
||
#define hash_state sha256ctx
|
||
|
||
#endif
|