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AES256 Exception in thread "main" Illegal key size or default parameters in Java

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In case of developing an application using the Java Cryptography Extension, and using a key length of more than 128 bits you encounter the following error.

JDK has a deliberate key size restriction by default, so you cannot use an encryption with key more than 128 bits. There is a code only solution. No need to download or mess with configuration files. It’s a reflection based solution, tested on java 8. Call this method once, early in your program.

Sample Code Snippet:

import javax.crypto.Cipher;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.Map;
// This class overides the permissions of java crypto librariespublic class Configclass {
	public static void fixKeyLength() {
	    String errorString = "Failed manually overriding key-length permissions.";
	    int newMaxKeyLength;
	    try {
	        if ((newMaxKeyLength = Cipher.getMaxAllowedKeyLength("AES")) < 256) {
	            Class c = Class.forName("javax.crypto.CryptoAllPermissionCollection");
	            Constructor con = c.getDeclaredConstructor();
	            Object allPermissionCollection = con.newInstance();
	            Field f = c.getDeclaredField("all_allowed");
	            f.setBoolean(allPermissionCollection, true);
	            c = Class.forName("javax.crypto.CryptoPermissions");
	            con = c.getDeclaredConstructor();
	            Object allPermissions = con.newInstance();
	            f = c.getDeclaredField("perms");
	            ((Map) f.get(allPermissions)).put("*", allPermissionCollection);
	            c = Class.forName("javax.crypto.JceSecurityManager");
	            f = c.getDeclaredField("defaultPolicy");
	            Field mf = Field.class.getDeclaredField("modifiers");
	            mf.setInt(f, f.getModifiers() & ~Modifier.FINAL);
	            f.set(null, allPermissions);
	            newMaxKeyLength = Cipher.getMaxAllowedKeyLength("AES");
	    } catch (Exception e) {
	        throw new RuntimeException(errorString, e);
	    if (newMaxKeyLength < 256)
	        throw new RuntimeException(errorString); // hack failed