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* SSU:

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- Ignore padding beyond last multiple of 16 (prep for obfuscation)
  - Comment out xor with 0 (version)
  - Don't need to zero IV buf before overwriting
* AES:
  - Decrypt speedup by XOR in place
  - Log if decrypt not mod 16
This commit is contained in:
zzz
2013-06-21 19:21:02 +00:00
parent 322e76d2a9
commit bb100de702
3 changed files with 31 additions and 9 deletions
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19
core/java/src/net/i2p/crypto/CryptixAESEngine.java
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@@ -127,6 +127,7 @@ public class CryptixAESEngine extends AESEngine {
/**
* @param iv 16 bytes
* @param length must be a multiple of 16 (will overrun to next mod 16 if not)
*/
@Override
public void decrypt(byte payload[], int payloadIndex, byte out[], int outIndex, SessionKey sessionKey, byte iv[], int length) {
@@ -135,6 +136,7 @@ public class CryptixAESEngine extends AESEngine {
/**
* @param iv 16 bytes starting at ivOffset
* @param length must be a multiple of 16 (will overrun to next mod 16 if not)
*/
@Override
public void decrypt(byte payload[], int payloadIndex, byte out[], int outIndex, SessionKey sessionKey, byte iv[], int ivOffset, int length) {
@@ -169,16 +171,25 @@ public class CryptixAESEngine extends AESEngine {
****/
int numblock = length / 16;
if (length % 16 != 0) numblock++;
if (length % 16 != 0) {
// may not work, it will overrun payload length and could AIOOBE
numblock++;
if (_log.shouldLog(Log.WARN))
_log.warn("not %16 " + length, new Exception());
}
byte prev[] = SimpleByteCache.acquire(16);
byte cur[] = SimpleByteCache.acquire(16);
System.arraycopy(iv, ivOffset, prev, 0, 16);
for (int x = 0; x < numblock; x++) {
System.arraycopy(payload, payloadIndex + (x * 16), cur, 0, 16);
decryptBlock(payload, payloadIndex + (x * 16), sessionKey, out, outIndex + (x * 16));
DataHelper.xor(out, outIndex + x * 16, prev, 0, out, outIndex + x * 16, 16);
System.arraycopy(payload, payloadIndex, cur, 0, 16);
decryptBlock(payload, payloadIndex, sessionKey, out, outIndex);
payloadIndex += 16;
//DataHelper.xor(out, outIndex + x * 16, prev, 0, out, outIndex + x * 16, 16);
for (int i = 0; i < 16; i++) {
out[outIndex++] ^= prev[i];
}
iv = prev; // just use IV to switch 'em around
prev = cur;
cur = iv;