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pqcrypto/crypto_kem/hqc-256-3-cca2/leaktime/util.c
Sebastian 4054af0c42 HQC submission (#202)
* Sebastian's HQC merge request

* Clean up changes to common infrastructure

* Fix Bitmask macro

It assumed that ``unsigned long`` was 64 bit

* Remove maxlen from nistseedexpander

It's a complicated thing to handle because the value is larger than size_t supports on 32-bit platforms

* Initialize buffers to help linter

* Add Nistseedexpander test

* Resolve UB in gf2x.c

Some of the shifts could be larger than WORD_SIZE_BITS, ie. larger than
the width of uint64_t. This apparently on Intel gets interpreted as the
shift mod 64, but on ARM something else happened.

* Fix Windows complaints

* rename log, exp which appear to be existing functions on MS

* Solve endianness problems

* remove all spaces before ';'

* Fix duplicate consistency

* Fix duplicate consistency

* Fix complaints by MSVC about narrowing int

* Add nistseedexpander.obj to COMMON_OBJECTS_NOPATH

* astyle format util.[ch]

* add util.h to makefile

* Sort includes in util.h

* Fix more Windows MSVC complaints

Co-authored-by: Sebastian Verschoor <sebastian@zeroknowledge.me>
Co-authored-by: Thom Wiggers <thom@thomwiggers.nl>
2021-03-24 21:02:46 +00:00

70 lines
1.9 KiB
C

#include "util.h"
#include "stddef.h"
#include "assert.h"
/* These functions should help with endianness-safe conversions
*
* load8 and store8 are copied from the McEliece implementations,
* which are in the public domain.
*/
void PQCLEAN_HQC2563CCA2_LEAKTIME_store8(unsigned char *out, uint64_t in) {
out[0] = (in >> 0x00) & 0xFF;
out[1] = (in >> 0x08) & 0xFF;
out[2] = (in >> 0x10) & 0xFF;
out[3] = (in >> 0x18) & 0xFF;
out[4] = (in >> 0x20) & 0xFF;
out[5] = (in >> 0x28) & 0xFF;
out[6] = (in >> 0x30) & 0xFF;
out[7] = (in >> 0x38) & 0xFF;
}
uint64_t PQCLEAN_HQC2563CCA2_LEAKTIME_load8(const unsigned char *in) {
uint64_t ret = in[7];
for (int8_t i = 6; i >= 0; i--) {
ret <<= 8;
ret |= in[i];
}
return ret;
}
void PQCLEAN_HQC2563CCA2_LEAKTIME_load8_arr(uint64_t *out64, size_t outlen, const uint8_t *in8, size_t inlen) {
size_t index_in = 0;
size_t index_out = 0;
// first copy by 8 bytes
if (inlen >= 8 && outlen >= 1) {
while (index_out < outlen && index_in + 8 <= inlen) {
out64[index_out] = PQCLEAN_HQC2563CCA2_LEAKTIME_load8(in8 + index_in);
index_in += 8;
index_out += 1;
}
}
// we now need to do the last 7 bytes if necessary
if (index_in >= inlen || index_out >= outlen) {
return;
}
out64[index_out] = in8[inlen - 1];
for (int8_t i = (int8_t)(inlen - index_in) - 2; i >= 0; i--) {
out64[index_out] <<= 8;
out64[index_out] |= in8[index_in + i];
}
}
void PQCLEAN_HQC2563CCA2_LEAKTIME_store8_arr(uint8_t *out8, size_t outlen, const uint64_t *in64, size_t inlen) {
for (size_t index_out = 0, index_in = 0; index_out < outlen && index_in < inlen;) {
out8[index_out] = (in64[index_in] >> ((index_out % 8) * 8)) & 0xFF;
index_out++;
if (index_out % 8 == 0) {
index_in++;
}
}
}