package cc.mrbird.febs.pay.util;
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import javax.crypto.Cipher;
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import java.lang.reflect.Field;
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import java.lang.reflect.Modifier;
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import java.security.NoSuchAlgorithmException;
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import java.security.Permission;
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import java.security.PermissionCollection;
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import java.util.Map;
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/**
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* 解决因jdk版本问题不支持aes256加密问题（Illegal key size or default parameters）
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*/
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public class JCEUtil {
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public static void removeCryptographyRestrictions() {
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if (!isRestrictedCryptography()) {
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System.out.println("Cryptography restrictions removal not needed");
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return;
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}
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try {
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/*
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* Do the following, but with reflection to bypass access checks:
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*
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* JceSecurity.isRestricted = false;
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* JceSecurity.defaultPolicy.perms.clear();
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* JceSecurity.defaultPolicy.add(CryptoAllPermission.INSTANCE);
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*/
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final Class<?> jceSecurity = Class.forName("javax.crypto.JceSecurity");
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final Class<?> cryptoPermissions = Class.forName("javax.crypto.CryptoPermissions");
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final Class<?> cryptoAllPermission = Class.forName("javax.crypto.CryptoAllPermission");
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final Field isRestrictedField = jceSecurity.getDeclaredField("isRestricted");
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isRestrictedField.setAccessible(true);
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//去除isRestricted的final限制
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final Field modifiersField = Field.class.getDeclaredField("modifiers");
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modifiersField.setAccessible(true);
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modifiersField.setInt(isRestrictedField, isRestrictedField.getModifiers() & ~Modifier.FINAL);
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isRestrictedField.set(null, false);
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final Field defaultPolicyField = jceSecurity.getDeclaredField("defaultPolicy");
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defaultPolicyField.setAccessible(true);
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final PermissionCollection defaultPolicy = (PermissionCollection) defaultPolicyField.get(null);
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final Field perms = cryptoPermissions.getDeclaredField("perms");
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perms.setAccessible(true);
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((Map<?, ?>) perms.get(defaultPolicy)).clear();
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final Field instance = cryptoAllPermission.getDeclaredField("INSTANCE");
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instance.setAccessible(true);
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defaultPolicy.add((Permission) instance.get(null));
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} catch (final Exception e) {
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e.printStackTrace();
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}
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}
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public static boolean isRestrictedCryptography() {
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// This matches Oracle Java 7 and 8, but not Java 9 or OpenJDK.
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final String name = System.getProperty("java.runtime.name");
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final String ver = System.getProperty("java.version");
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return name != null && name.equals("Java(TM) SE Runtime Environment")
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&& ver != null && (ver.startsWith("1.7") || ver.startsWith("1.8"));
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}
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public static void main(String[] args) throws NoSuchAlgorithmException {
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// removeCryptographyRestrictions();
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long length = Cipher.getMaxAllowedKeyLength("AES/CBC/PKCS5Padding");
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System.out.println(length);
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}
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}
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