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package neembuu.uploader.utils;

import java.lang.reflect.Field;
import java.security.Permission;
import java.security.PermissionCollection;
import java.util.Map;
import java.util.logging.Level;

/**
 *
 * @author Paralytic
 */
public class RemoveCryptographyRestrictions {
    public static void removeCryptographyRestrictions() {
        if (!isRestrictedCryptography()) {
            NULogger.getLogger().info("Cryptography restrictions removal not needed");
            return;
        }
        try {
            /*
             * Do the following, but with reflection to bypass access checks:
             *
             * JceSecurity.isRestricted = false;
             * JceSecurity.defaultPolicy.perms.clear();
             * JceSecurity.defaultPolicy.add(CryptoAllPermission.INSTANCE);
             */
            final Class<?> jceSecurity = Class.forName("javax.crypto.JceSecurity");
            final Class<?> cryptoPermissions = Class.forName("javax.crypto.CryptoPermissions");
            final Class<?> cryptoAllPermission = Class.forName("javax.crypto.CryptoAllPermission");

            final Field isRestrictedField = jceSecurity.getDeclaredField("isRestricted");
            isRestrictedField.setAccessible(true);
            isRestrictedField.set(null, false);

            final Field defaultPolicyField = jceSecurity.getDeclaredField("defaultPolicy");
            defaultPolicyField.setAccessible(true);
            final PermissionCollection defaultPolicy = (PermissionCollection) defaultPolicyField.get(null);

            final Field perms = cryptoPermissions.getDeclaredField("perms");
            perms.setAccessible(true);
            ((Map<?, ?>) perms.get(defaultPolicy)).clear();

            final Field instance = cryptoAllPermission.getDeclaredField("INSTANCE");
            instance.setAccessible(true);
            defaultPolicy.add((Permission) instance.get(null));

            NULogger.getLogger().info("Successfully removed cryptography restrictions");
        } catch (final Exception e) {
            NULogger.getLogger().log(Level.WARNING, "Failed to remove cryptography restrictions", e);
        }
    }

    private static boolean isRestrictedCryptography() {
        // This simply matches the Oracle JRE, but not OpenJDK.
        return "Java(TM) SE Runtime Environment".equals(System.getProperty("java.runtime.name"));
    }
}