背景:在集成钉钉或者企微API时回调接口需要使用32位长(258bit)密钥解密服务器回传的加密信息,在代码执行至cipher.init(2, keySpec, iv)时报java.security.InvalidKeyException: Illegal key size错误。
原因:JDK受版本安全限制,默认只允许128位长度以内的。秘钥长度,如果密钥大于128, 会抛出java.security.InvalidKeyException: Illegal key size 异常. java运行时环境默认读到的是受限的policy文件. 文件位于${java_home}/jre/lib/security, 这种限制是因为美国对软件出口的控制所造成的的.JDK1.8之后已经兼容了该问题。
跟踪代码:
Cipher#passCryptoPermCheck().engineGetKeySize()
取当AES编码传入的aesKey的长度*8为一个编码长度单元,笔者使用的企微的AES编码长度为32位,即一个编码存储长度为32*8 =256个bit。
JDK的AES默认加密限制长度是128bit,即使用16字节的长度进行分组加密密文填充
javax.crypto.CryptoPermissions@db743bc (
(CryptoPermission RC2 128 , effective 128)
(CryptoPermission RSA 2147483647)
(CryptoPermission RC4 128)
(CryptoPermission DES 64)
(CryptoPermission RC5 128 , rounds 12)
(CryptoPermission DESEDE 2147483647)
(CryptoPermission * 128)
)
所以,当前机器的加密编码的加密键为4个byte的编码格式。
故在长度校验的时候会报异常。
解决方案:去官方下载JCE无限制权限策略文件。
解决方案:
1,升级不受限制JDK版本
升级JDK9级以上版本,未测试
2,替换JDK受限文件级配置
JDK7的下载地址: Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files 7 Download
JDK8的下载地址: JCE Unlimited Strength Jurisdiction Policy Files for JDK/JRE 8 Download
下载后解压,可以看到local_policy.jar和US_export_policy.jar以及readme.txt
如果安装了JRE,将两个jar文件放到%JRE_HOME%\lib\security目录下覆盖原来的文件
如果安装了JDK,还要将两个jar文件也放到%JDK_HOME%\jre\lib\security目录下覆盖原来文件
3,JDK1.8 代码策略修改
JDK1.8 已经支持不受限的jar,但配置默认是受限的
修改代码配置,在加密之前,修改不受限配置.
WXBizMsgCrypt wxcpt = createWXBizMsgCrypt(suiteId, getCorpId(postData), false);
Security.setProperty("crypto.policy", "unlimited");
sMsg = wxcpt.decryptMsg(msgSignature, timestamp, nonce, postData);
Security.setProperty("crypto.policy", "unlimited"); 本方案已测试
4,自定义加密封装
1,代码去除限制算法
参考博客https://blog.csdn.net/weixin_39265427/article/details/106505502
package com.service;
import javax.crypto.Cipher;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.security.NoSuchAlgorithmException;
import java.security.Permission;
import java.security.PermissionCollection;
import java.util.Map;
public class JCEUtil {
private static void removeCryptographyRestrictions() {
if (!isRestrictedCryptography()) {
System.out.println("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);
//去除isRestricted的final限制
final Field modifiersField = Field.class.getDeclaredField("modifiers");
modifiersField.setAccessible(true);
modifiersField.setInt(isRestrictedField, isRestrictedField.getModifiers() & ~Modifier.FINAL);
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));
} catch (final Exception e) {
e.printStackTrace();
}
}
private static boolean isRestrictedCryptography() {
// This matches Oracle Java 7 and 8, but not Java 9 or OpenJDK.
final String name = System.getProperty("java.runtime.name");
final String ver = System.getProperty("java.version");
return name != null && name.equals("Java(TM) SE Runtime Environment")
&& ver != null && (ver.startsWith("1.7") || ver.startsWith("1.8"));
}
public static void main(String[] args) throws NoSuchAlgorithmException {
// removeCryptographyRestrictions();
long length = Cipher.getMaxAllowedKeyLength("AES/CBC/PKCS5Padding");
System.out.println(length);
}
}
2,分段算法加密
下面参考 https://blog.csdn.net/centralperk/article/details/8538697#
package security;
import java.io.ByteArrayOutputStream;
import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;
import javax.crypto.Cipher;
/** *//**
* <p>
* RSA公钥/私钥/签名工具包
* </p>
* <p>
* 罗纳德·李维斯特(Ron [R]ivest)、阿迪·萨莫尔(Adi [S]hamir)和伦纳德·阿德曼(Leonard [A]dleman)
* </p>
* <p>
* 字符串格式的密钥在未在特殊说明情况下都为BASE64编码格式<br/>
* 由于非对称加密速度极其缓慢,一般文件不使用它来加密而是使用对称加密,<br/>
* 非对称加密算法可以用来对对称加密的密钥加密,这样保证密钥的安全也就保证了数据的安全
* </p>
*
* @author IceWee
* @date 2012-4-26
* @version 1.0
*/
public class RSAUtils {
/** *//**
* 加密算法RSA
*/
public static final String KEY_ALGORITHM = "RSA";
/** *//**
* 签名算法
*/
public static final String SIGNATURE_ALGORITHM = "MD5withRSA";
/** *//**
* 获取公钥的key
*/
private static final String PUBLIC_KEY = "RSAPublicKey";
/** *//**
* 获取私钥的key
*/
private static final String PRIVATE_KEY = "RSAPrivateKey";
/** *//**
* RSA最大加密明文大小
*/
private static final int MAX_ENCRYPT_BLOCK = 117;
/** *//**
* RSA最大解密密文大小
*/
private static final int MAX_DECRYPT_BLOCK = 128;
/** *//**
* <p>
* 生成密钥对(公钥和私钥)
* </p>
*
* @return
* @throws Exception
*/
public static Map<String, Object> genKeyPair() throws Exception {
KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);
keyPairGen.initialize(1024);
KeyPair keyPair = keyPairGen.generateKeyPair();
RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
Map<String, Object> keyMap = new HashMap<String, Object>(2);
keyMap.put(PUBLIC_KEY, publicKey);
keyMap.put(PRIVATE_KEY, privateKey);
return keyMap;
}
/** *//**
* <p>
* 用私钥对信息生成数字签名
* </p>
*
* @param data 已加密数据
* @param privateKey 私钥(BASE64编码)
*
* @return
* @throws Exception
*/
public static String sign(byte[] data, String privateKey) throws Exception {
byte[] keyBytes = Base64Utils.decode(privateKey);
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
PrivateKey privateK = keyFactory.generatePrivate(pkcs8KeySpec);
Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
signature.initSign(privateK);
signature.update(data);
return Base64Utils.encode(signature.sign());
}
/** *//**
* <p>
* 校验数字签名
* </p>
*
* @param data 已加密数据
* @param publicKey 公钥(BASE64编码)
* @param sign 数字签名
*
* @return
* @throws Exception
*
*/
public static boolean verify(byte[] data, String publicKey, String sign)
throws Exception {
byte[] keyBytes = Base64Utils.decode(publicKey);
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
PublicKey publicK = keyFactory.generatePublic(keySpec);
Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
signature.initVerify(publicK);
signature.update(data);
return signature.verify(Base64Utils.decode(sign));
}
/** *//**
* <P>
* 私钥解密
* </p>
*
* @param encryptedData 已加密数据
* @param privateKey 私钥(BASE64编码)
* @return
* @throws Exception
*/
public static byte[] decryptByPrivateKey(byte[] encryptedData, String privateKey)
throws Exception {
byte[] keyBytes = Base64Utils.decode(privateKey);
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.DECRYPT_MODE, privateK);
int inputLen = encryptedData.length;
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] cache;
int i = 0;
// 对数据分段解密
while (inputLen - offSet > 0) {
if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
} else {
cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_DECRYPT_BLOCK;
}
byte[] decryptedData = out.toByteArray();
out.close();
return decryptedData;
}
/** *//**
* <p>
* 公钥解密
* </p>
*
* @param encryptedData 已加密数据
* @param publicKey 公钥(BASE64编码)
* @return
* @throws Exception
*/
public static byte[] decryptByPublicKey(byte[] encryptedData, String publicKey)
throws Exception {
byte[] keyBytes = Base64Utils.decode(publicKey);
X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key publicK = keyFactory.generatePublic(x509KeySpec);
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.DECRYPT_MODE, publicK);
int inputLen = encryptedData.length;
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] cache;
int i = 0;
// 对数据分段解密
while (inputLen - offSet > 0) {
if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
} else {
cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_DECRYPT_BLOCK;
}
byte[] decryptedData = out.toByteArray();
out.close();
return decryptedData;
}
/** *//**
* <p>
* 公钥加密
* </p>
*
* @param data 源数据
* @param publicKey 公钥(BASE64编码)
* @return
* @throws Exception
*/
public static byte[] encryptByPublicKey(byte[] data, String publicKey)
throws Exception {
byte[] keyBytes = Base64Utils.decode(publicKey);
X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key publicK = keyFactory.generatePublic(x509KeySpec);
// 对数据加密
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.ENCRYPT_MODE, publicK);
int inputLen = data.length;
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] cache;
int i = 0;
// 对数据分段加密
while (inputLen - offSet > 0) {
if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
} else {
cache = cipher.doFinal(data, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_ENCRYPT_BLOCK;
}
byte[] encryptedData = out.toByteArray();
out.close();
return encryptedData;
}
/** *//**
* <p>
* 私钥加密
* </p>
*
* @param data 源数据
* @param privateKey 私钥(BASE64编码)
* @return
* @throws Exception
*/
public static byte[] encryptByPrivateKey(byte[] data, String privateKey)
throws Exception {
byte[] keyBytes = Base64Utils.decode(privateKey);
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.ENCRYPT_MODE, privateK);
int inputLen = data.length;
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] cache;
int i = 0;
// 对数据分段加密
while (inputLen - offSet > 0) {
if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
} else {
cache = cipher.doFinal(data, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_ENCRYPT_BLOCK;
}
byte[] encryptedData = out.toByteArray();
out.close();
return encryptedData;
}
/** *//**
* <p>
* 获取私钥
* </p>
*
* @param keyMap 密钥对
* @return
* @throws Exception
*/
public static String getPrivateKey(Map<String, Object> keyMap)
throws Exception {
Key key = (Key) keyMap.get(PRIVATE_KEY);
return Base64Utils.encode(key.getEncoded());
}
/** *//**
* <p>
* 获取公钥
* </p>
*
* @param keyMap 密钥对
* @return
* @throws Exception
*/
public static String getPublicKey(Map<String, Object> keyMap)
throws Exception {
Key key = (Key) keyMap.get(PUBLIC_KEY);
return Base64Utils.encode(key.getEncoded());
}
}```