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NTRU Prime: more unary negations

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This commit is contained in:
John M. Schanck 2020-09-01 17:15:01 -04:00
parent a5b5633534
commit 7f3228a9b3
3 changed files with 3 additions and 3 deletions
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2
crypto_kem/sntrup653/clean/crypto_core_invsntrup653.c
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@ -15,7 +15,7 @@
static int int16_nonzero_mask(int16 x) { static int int16_nonzero_mask(int16 x) {
uint16 u = (uint16) x; /* 0, else 1...65535 */ uint16 u = (uint16) x; /* 0, else 1...65535 */
uint32 v = u; /* 0, else 1...65535 */ uint32 v = u; /* 0, else 1...65535 */
v = -v; /* 0, else 2^32-65535...2^32-1 */ v = ~v + 1; /* 0, else 2^32-65535...2^32-1 */
v >>= 31; /* 0, else 1 */ v >>= 31; /* 0, else 1 */
return -(int) v; /* 0, else -1 */ return -(int) v; /* 0, else -1 */
} }

2
crypto_kem/sntrup761/clean/crypto_core_invsntrup761.c
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@ -15,7 +15,7 @@
static int int16_nonzero_mask(int16 x) { static int int16_nonzero_mask(int16 x) {
uint16 u = (uint16) x; /* 0, else 1...65535 */ uint16 u = (uint16) x; /* 0, else 1...65535 */
uint32 v = u; /* 0, else 1...65535 */ uint32 v = u; /* 0, else 1...65535 */
v = -v; /* 0, else 2^32-65535...2^32-1 */ v = ~v + 1; /* 0, else 2^32-65535...2^32-1 */
v >>= 31; /* 0, else 1 */ v >>= 31; /* 0, else 1 */
return -(int) v; /* 0, else -1 */ return -(int) v; /* 0, else -1 */
} }

2
crypto_kem/sntrup857/clean/crypto_core_invsntrup857.c
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@ -15,7 +15,7 @@
static int int16_nonzero_mask(int16 x) { static int int16_nonzero_mask(int16 x) {
uint16 u = (uint16) x; /* 0, else 1...65535 */ uint16 u = (uint16) x; /* 0, else 1...65535 */
uint32 v = u; /* 0, else 1...65535 */ uint32 v = u; /* 0, else 1...65535 */
v = -v; /* 0, else 2^32-65535...2^32-1 */ v = ~v + 1; /* 0, else 2^32-65535...2^32-1 */
v >>= 31; /* 0, else 1 */ v >>= 31; /* 0, else 1 */
return -(int) v; /* 0, else -1 */ return -(int) v; /* 0, else -1 */
} }