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Merge pull request #157 from dmitrystu/optimized-loop 

loop optimization
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kokke 2020-03-07 02:51:39 +01:00 committed by GitHub
parent 3fe133ffa3 6be2e11a23
commit 1933872bba
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 17 additions and 18 deletions
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35
aes.c
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@ -412,23 +412,23 @@ static void Cipher(state_t* state, const uint8_t* RoundKey)
uint8_t round = 0;
// Add the First round key to the state before starting the rounds.
AddRoundKey(0, state, RoundKey);
AddRoundKey(0, state, RoundKey);
// There will be Nr rounds.
// The first Nr-1 rounds are identical.
// These Nr-1 rounds are executed in the loop below.
for (round = 1; round < Nr; ++round)
// These Nr rounds are executed in the loop below.
// Last one without MixColumns()
for (round = 1; ; ++round)
{
SubBytes(state);
ShiftRows(state);
if (round == Nr) {
break;
}
MixColumns(state);
AddRoundKey(round, state, RoundKey);
}
// The last round is given below.
// The MixColumns function is not here in the last round.
SubBytes(state);
ShiftRows(state);
// Add round key to last round
AddRoundKey(Nr, state, RoundKey);
}
@ -438,24 +438,23 @@ static void InvCipher(state_t* state, const uint8_t* RoundKey)
uint8_t round = 0;
// Add the First round key to the state before starting the rounds.
AddRoundKey(Nr, state, RoundKey);
AddRoundKey(Nr, state, RoundKey);
// There will be Nr rounds.
// The first Nr-1 rounds are identical.
// These Nr-1 rounds are executed in the loop below.
for (round = (Nr - 1); round > 0; --round)
// These Nr rounds are executed in the loop below.
// Last one without InvMixColumn()
for (round = (Nr - 1); ; --round)
{
InvShiftRows(state);
InvSubBytes(state);
AddRoundKey(round, state, RoundKey);
if (round == 0) {
break;
}
InvMixColumns(state);
}
// The last round is given below.
// The MixColumns function is not here in the last round.
InvShiftRows(state);
InvSubBytes(state);
AddRoundKey(0, state, RoundKey);
}
#endif // #if (defined(CBC) && CBC == 1) || (defined(ECB) && ECB == 1)