Java Security doesn't support AES-256 in default

The below code in AesExample.java generates an AES-256 key,

KeyGenerator keyGen = KeyGenerator.getInstance("AES");
keyGen.init(256);
Key key = keyGen.generateKey();

but the exception happens when running java AesExample.

The reason is the import regulation in some countries. AES is limited to 128 bits in default security policy.

Algorithm	Maximum Keysize
DES	64
DESede	*
RC2	128
RC4	128
RC5	128
RSA	*
all others	128

We can change the security policy by downloading the zip from the site.

http://www.oracle.com/technetwork/java/javase/downloads/index.html

Please select "Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files for JDK/JRE 8" to download the zip file, jce_policy-8.zip, if we use JDK 8.

Decompress the ZIP file to get the both jar files.

local_policy.jar

US_export_policy.jar

Copy them to the directory to replace old files.

JAVA_HOME\jre\lib\security

Now we can use AES-256 in Java environment.

>javac AesExample.java

>java AesExample

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