sha256.h File Reference

Implementation of the SHA-256 hashing algorithm. More...

Go to the source code of this file.

Classes
struct	SHA256_ctx_t
	Structure that holds context information for SHA-256 operations. More...

Macros
#define	SHA256_BLOCK_SIZE   32
	SHA256 outputs a 32 byte digest.

Functions
void	sha256_init (SHA256_ctx_t *ctx)
	Initializes the SHA-256 context. More...
void	sha256_update (SHA256_ctx_t *ctx, const uint8_t data[], size_t len)
	Adds data to the SHA-256 context for hashing. More...
void	sha256_final (SHA256_ctx_t *ctx, uint8_t hash[])
	Finalizes the hashing and produces the final SHA-256 digest. More...
void	sha256_bytes_to_hex (uint8_t *src, size_t src_length, char *out, size_t out_length)
	Converts a byte array to its hexadecimal string representation. More...

Detailed Description

Implementation of the SHA-256 hashing algorithm.

The original code was written by Brad Conte, and is available at: https://github.com/B-Con/crypto-algorithms

SHA-256 is one of the three algorithms in the SHA2 specification. The others, SHA-384 and SHA-512, are not offered in this implementation. Algorithm specification can be found here: http://csrc.nist.gov/publications/fips/fips180-2/fips180-2withchangenotice.pdf This implementation uses little endian byte order.

Function Documentation

sha256_bytes_to_hex()

void sha256_bytes_to_hex	(	uint8_t *	src,
		size_t	src_length,
		char *	out,
		size_t	out_length
	)

Converts a byte array to its hexadecimal string representation.

Parameters

src	Pointer to the source byte array.
src_length	Length of the source byte array.
out	Pointer to the output buffer for the hexadecimal string.
out_length	Length of the output buffer (must be at least 2 * src_length + 1).

The output string will be null-terminated if the buffer is large enough.

Converts a byte array to its hexadecimal string representation.

Parameters

src	Pointer to the source byte array.
src_length	Length of the source byte array.
out	Pointer to the output buffer for the hexadecimal string.
out_length	Length of the output buffer (must be at least 2 * src_length + 1).

The output string will be null-terminated if the buffer is large enough.

sha256_final()

void sha256_final	(	SHA256_ctx_t *	ctx,
		uint8_t	hash[]
	)

Finalizes the hashing and produces the final SHA-256 digest.

Parameters

ctx	Pointer to the SHA-256 context.
hash	Pointer to a buffer where the final hash will be stored (must be at least 32 bytes long).

sha256_init()

void sha256_init

(

SHA256_ctx_t *

ctx

)

Initializes the SHA-256 context.

Parameters

ctx	Pointer to the SHA-256 context to initialize.

sha256_update()

void sha256_update	(	SHA256_ctx_t *	ctx,
		const uint8_t	data[],
		size_t	len
	)

Adds data to the SHA-256 context for hashing.

Parameters

ctx	Pointer to the SHA-256 context.
data	Pointer to the data to be hashed.
len	Length of the data to hash, in bytes.