XMSS Library
Macros | Functions
override_sha256_internal.h File Reference

Prototype for the SHA-256 hash function override using the internal interface. More...

#include <stdint.h>
#include "types.h"
Include dependency graph for override_sha256_internal.h:

Go to the source code of this file.

Macros

#define XMSS_OVERRIDE_SHA256_INTERNAL_H_INCLUDED
 Include guard.
 

Functions

void xmss_sha256_process_block (XmssNativeValue256 *Hi, const uint32_t *Mi)
 Update the intermediate SHA-256 hash value $H_i$ by processing a single, additional message block $M_i$. More...
 

Detailed Description

Prototype for the SHA-256 hash function override using the internal interface.

Include this file in your override implementation for SHA-256 using the internal interface.

The library allows to override its internal implementation for SHA-256. The main use case is hardware acceleration.

If your platform is compatible with the internal format of the library, then it is preferred to use the internal interface specified here rather than the generic interface.

The internal interface has the following properties:

  • Allocation free
  • The intermediate hash value $H_i$ is 32-bit aligned.
  • The intermediate hash value $H_i$ consists of 8 uint32_t values, each in native byte ordering.
  • The block $M_i$ is 32-bit aligned.
  • The block $M_i$ consists of 16 uint32_t values, each in native byte ordering.
  • The intermediate hash value $H_i$ is modified in-place.

This interface prevents unnecessary copying of memory, unnecessary byte swapping, and alignment issues.

Compile the library with CMake as follows:

cmake -DXMSS_SHA256=OverrideInternal

Function Documentation

◆ xmss_sha256_process_block()

void xmss_sha256_process_block ( XmssNativeValue256 *  Hi,
const uint32_t *  Mi 
)

Update the intermediate SHA-256 hash value $H_i$ by processing a single, additional message block $M_i$.

This function implements the loop body of the SHA-256($M$) function as defined by NIST FIPS 180-4, Section 6.2.2, Steps 1, 2, 3, and 4.

For performance reasons, it is recommended not to validate the input. This function is guaranteed to be called by the library with valid input.

Parameters
[in,out]HiIntermediate hash value $H_i$ in native form.
[in]MiMessage block $M_i$ in native form (uint32_t[16] == 64 bytes).