Skip to content

Instantly share code, notes, and snippets.

View chenchun's full-sized avatar
🦖
go for{vacation()}

Chun Chen chenchun

🦖
go for{vacation()}
View GitHub Profile
@jehrhardt
jehrhardt / KeyLengthDetector.java
Created March 15, 2013 06:23
Detect the allowed size of AES keys on the JVM. If the size is <= 256, it is limited. To fix it JCE unlimted stregth files are needed.
import javax.crypto.Cipher;
import java.security.NoSuchAlgorithmException;
public class KeyLengthDetector {
public static void main(String[] args) {
int allowedKeyLength = 0;
try {
allowedKeyLength = Cipher.getMaxAllowedKeyLength("AES");
} catch (NoSuchAlgorithmException e) {
@hellerbarde
hellerbarde / latency.markdown
Created May 31, 2012 13:16 — forked from jboner/latency.txt
Latency numbers every programmer should know

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs