diff options
| author | Michael Brown <mcb30@ipxe.org> | 2024-11-27 12:51:04 +0000 |
|---|---|---|
| committer | Michael Brown <mcb30@ipxe.org> | 2024-11-27 13:05:18 +0000 |
| commit | 7c2e68cc87a552c153e13517b0d0d6827f48e95b (patch) | |
| tree | 234e3fee7656c0659207d84bb3eefc269551ddc6 /src/include/ipxe/bigint.h | |
| parent | 9cbf5c4f86b45773badec2498fac22e8bc6d7dd1 (diff) | |
| download | ipxe-7c2e68cc87a552c153e13517b0d0d6827f48e95b.tar.gz | |
[crypto] Eliminate temporary working space for bigint_mod_invert()
With a slight modification to the algorithm to ignore bits of the
residue that can never contribute to the result, it is possible to
reuse the as-yet uncalculated portions of the inverse to hold the
residue. This removes the requirement for additional temporary
working space.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Diffstat (limited to 'src/include/ipxe/bigint.h')
| -rw-r--r-- | src/include/ipxe/bigint.h | 24 |
1 files changed, 5 insertions, 19 deletions
diff --git a/src/include/ipxe/bigint.h b/src/include/ipxe/bigint.h index 330d7deec..e55c536c7 100644 --- a/src/include/ipxe/bigint.h +++ b/src/include/ipxe/bigint.h @@ -242,31 +242,18 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); } while ( 0 ) /** - * Compute inverse of odd big integer modulo its own size + * Compute inverse of odd big integer modulo any power of two * * @v invertend Odd big integer to be inverted * @v inverse Big integer to hold result - * @v tmp Temporary working space */ -#define bigint_mod_invert( invertend, inverse, tmp ) do { \ - unsigned int size = bigint_size (invertend); \ +#define bigint_mod_invert( invertend, inverse ) do { \ + unsigned int size = bigint_size ( invertend ); \ bigint_mod_invert_raw ( (invertend)->element, \ - (inverse)->element, size, tmp ); \ + (inverse)->element, size ); \ } while ( 0 ) /** - * Calculate temporary working space required for modular inversion - * - * @v invertend Odd big integer to be inverted - * @ret len Length of temporary working space - */ -#define bigint_mod_invert_tmp_len( invertend ) ( { \ - unsigned int size = bigint_size (invertend); \ - sizeof ( struct { \ - bigint_t ( size ) temp_residue; \ - } ); } ) - -/** * Perform modular multiplication of big integers * * @v multiplicand Big integer to be multiplied @@ -408,8 +395,7 @@ void bigint_multiply_raw ( const bigint_element_t *multiplicand0, void bigint_reduce_raw ( bigint_element_t *modulus0, bigint_element_t *value0, unsigned int size ); void bigint_mod_invert_raw ( const bigint_element_t *invertend0, - bigint_element_t *inverse0, - unsigned int size, void *tmp ); + bigint_element_t *inverse0, unsigned int size ); void bigint_mod_multiply_raw ( const bigint_element_t *multiplicand0, const bigint_element_t *multiplier0, const bigint_element_t *modulus0, |