signet::forge::crypto::detail::aes Namespace Reference

Functions
constexpr uint8_t	xtime (uint8_t a)
	Multiply by x (i.e., by 2) in GF(2^8).
constexpr uint8_t	gf_mul (uint8_t a, uint8_t b)
	Multiply two elements in GF(2^8) using the Russian peasant algorithm.
void	sub_word (uint8_t word[4])
	Apply S-box to each byte of a 4-byte word.
void	rot_word (uint8_t word[4])
	Rotate a 4-byte word left by one byte: [a,b,c,d] -> [b,c,d,a].
void	secure_zero (void *ptr, size_t len)
	Securely zero memory that held key material (CWE-244, NIST SP 800-38D §8.3).
bool	has_hardware_aes () noexcept
	Check if CPU supports AES-NI (x86) or ARMv8-CE AES (ARM).

Function Documentation

gf_mul()

constexpr uint8_t signet::forge::crypto::detail::aes::gf_mul ( uint8_t  a, uint8_t  b  )

inlineconstexpr

Multiply two elements in GF(2^8) using the Russian peasant algorithm.

Constant-time: arithmetic masking instead of branches (CWE-208). This is used for MixColumns and InvMixColumns (FIPS-197 §5.1.3/§5.3.3).

Definition at line 165 of file aes_core.hpp.

has_hardware_aes()

bool signet::forge::crypto::detail::aes::has_hardware_aes ( )

inlinenoexcept

Check if CPU supports AES-NI (x86) or ARMv8-CE AES (ARM).

Returns true if hardware AES acceleration is available. Currently used for diagnostics only — T-table path is always used (Gap C-5).

Definition at line 217 of file aes_core.hpp.

rot_word()

void signet::forge::crypto::detail::aes::rot_word ( uint8_t  word[4] )

inline

Rotate a 4-byte word left by one byte: [a,b,c,d] -> [b,c,d,a].

Definition at line 189 of file aes_core.hpp.

secure_zero()

void signet::forge::crypto::detail::aes::secure_zero ( void *  ptr, size_t  len  )

inline

Securely zero memory that held key material (CWE-244, NIST SP 800-38D §8.3).

Uses volatile write + compiler barrier to prevent dead-store elimination. This is the approach used by libsodium and BoringSSL — portable across all compilers and platforms without relying on non-standard APIs.

Note

CWE-244: clearing of heap memory containing sensitive information.

Definition at line 203 of file aes_core.hpp.

sub_word()

void signet::forge::crypto::detail::aes::sub_word ( uint8_t  word[4] )

inline

Apply S-box to each byte of a 4-byte word.

Definition at line 181 of file aes_core.hpp.

xtime()

constexpr uint8_t signet::forge::crypto::detail::aes::xtime ( uint8_t  a )

inlineconstexpr

Multiply by x (i.e., by 2) in GF(2^8).

This is the "xtime" operation. If the high bit is set, XOR with 0x1b after shifting (reduction mod 0x11b).

Definition at line 158 of file aes_core.hpp.