helper functions for sys_crypto_modes More...

Detailed Description

helper functions for sys_crypto_modes

Author: Freie Universitaet Berlin, Computer Systems & Telematics; Nico von Geyso nico..nosp@m.geys.nosp@m.o@fu-.nosp@m.berl.nosp@m.in.de

Definition in file helper.h.

#include <stddef.h>
#include <stdint.h>

Include dependency graph for helper.h:

void	crypto_block_inc_ctr (uint8_t block[16], int L)
	Increment a counter encoded in an 16 octet block.

int	crypto_equals (const uint8_t a, const uint8_t b, size_t len)
	Compares two blocks of same size in deterministic time.

void	crypto_secure_wipe (void *buf, size_t len)
	Secure wipe function.

Function Documentation

◆ crypto_block_inc_ctr()

void crypto_block_inc_ctr	(	uint8_t	block[16],
		int	L
	)

Increment a counter encoded in an 16 octet block.

The counter is encoded from the least significant bit in the following form: block[15-L..15])

Parameters

block	encoded block
L	length of counter

◆ crypto_equals()

int crypto_equals	(	const uint8_t *	a,
		const uint8_t *	b,
		size_t	len
	)

Compares two blocks of same size in deterministic time.

Parameters

a	block a
b	block b
len	size of both blocks

Returns: 0 iff the blocks are non-equal.

◆ crypto_secure_wipe()

void crypto_secure_wipe	(	void *	buf,
		size_t	len
	)

Secure wipe function.

This wipe function zeros the supplied buffer in a way that the compiler is not allowed to optimize. This can be used to erase secrets from memory.

Note that this function on its own could be insufficient against (data remanence) attacks. It is outside the scope of this function to thoroughly shred the memory area.

Parameters

[in]	buf	buffer to wipe
[in]	len	size of the buffer in bytes