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public class DSA {
public static final String ALGORITHM = "DSA";
/**
* 默认密钥字节数
*
* <pre>
* DSA
* Default Keysize 1024
* Keysize must be a multiple of 64, ranging from 512 to 1024 (inclusive).
* </pre>
*/
private static final int KEY_SIZE = 1024;
/**
* 默认种子
*/
private static final String DEFAULT_SEED = "asdfasdfafdasdfasdfasdfasdf";
private static final String PUBLIC_KEY = "PublicKey";
private static final String PRIVATE_KEY = "PrivateKey";
/**
* 用私钥对信息生成数字签名
*
* @param data
* 加密数据
* @param privateKey
* 私钥
*
* @return
* @throws Exception
*/
public static String sign(String content, String privateKey, String input_charset) throws Exception {
// 解密由base64编码的私钥
byte[] keyBytes = Base64.decode(privateKey);
// 构造PKCS8EncodedKeySpec对象
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
// KEY_ALGORITHM 指定的加密算法
KeyFactory keyFactory = KeyFactory.getInstance(ALGORITHM);
// 取私钥匙对象
PrivateKey priKey = keyFactory.generatePrivate(pkcs8KeySpec);
// 用私钥对信息生成数字签名
Signature signature = Signature.getInstance(keyFactory.getAlgorithm());
signature.initSign(priKey);
signature.update(content.getBytes(input_charset));
return Base64.encode(signature.sign());
}
/**
* 校验数字签名
*
* @param data
* 加密数据
* @param publicKey
* 公钥
* @param sign
* 数字签名
*
* @return 校验成功返回true 失败返回false
* @throws Exception
*
*/
public static boolean verify(String content, String sign, String publicKey, String input_charset) throws Exception {
// ALGORITHM 指定的加密算法
KeyFactory keyFactory = KeyFactory.getInstance(ALGORITHM);
// 解密由base64编码的公钥
byte[] keyBytes = Base64.decode(publicKey);
// 构造X509EncodedKeySpec对象
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
// 取公钥匙对象
PublicKey pubKey = keyFactory.generatePublic(keySpec);
Signature signature = Signature.getInstance(keyFactory.getAlgorithm());
signature.initVerify(pubKey);
signature.update(content.getBytes(input_charset));
// 验证签名是否正常
return signature.verify(Base64.decode(sign));
}
/**
* 生成密钥
*
* @param seed
* 种子
* @return 密钥对象
* @throws Exception
*/
public static Map<String, Object> initKey(String seed) throws Exception {
KeyPairGenerator keygen = KeyPairGenerator.getInstance(ALGORITHM);
// 初始化随机产生器
SecureRandom secureRandom = new SecureRandom();
secureRandom.setSeed(seed.getBytes());
keygen.initialize(KEY_SIZE, secureRandom);
KeyPair keys = keygen.genKeyPair();
DSAPublicKey publicKey = (DSAPublicKey) keys.getPublic();
DSAPrivateKey privateKey = (DSAPrivateKey) keys.getPrivate();
Map<String, Object> map = new HashMap<String, Object>(2);
map.put(PUBLIC_KEY, publicKey);
map.put(PRIVATE_KEY, privateKey);
return map;
}
/**
* 默认生成密钥
*
* @return 密钥对象
* @throws Exception
*/
public static Map<String, Object> initKey() throws Exception {
return initKey(DEFAULT_SEED);
}
/**
* 取得私钥
*
* @param keyMap
* @return
* @throws Exception
*/
public static String getPrivateKey(Map<String, Object> keyMap) throws Exception {
Key key = (Key) keyMap.get(PRIVATE_KEY);
return Base64.encode(key.getEncoded());
}
/**
* 取得公钥
*
* @param keyMap
* @return
* @throws Exception
*/
public static String getPublicKey(Map<String, Object> keyMap) throws Exception {
Key key = (Key) keyMap.get(PUBLIC_KEY);
return Base64.encode(key.getEncoded());
}
public static void main(String[] args) {
try {
String inputStr = "abc";
// 构建密钥
Map<String, Object> keyMap = DSA.initKey();
// 获得密钥
String publicKey = DSA.getPublicKey(keyMap);
String privateKey = DSA.getPrivateKey(keyMap);
// 产生签名
String sign = DSA.sign(inputStr, privateKey, "UTF-8");
System.out.println("签名:\r" + sign);
byte[] keyBytes = Base64.decode(publicKey);
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(ALGORITHM);
PublicKey pubKey = keyFactory.generatePublic(keySpec);
Signature signature = Signature.getInstance(keyFactory.getAlgorithm());
signature.initVerify(pubKey);
signature.update(inputStr.getBytes("UTF-8"));
System.out.println("状态1:\r" + signature.verify(Base64.decode(sign)));
// 验证签名
boolean status = DSA.verify(inputStr, publicKey, sign, "UTF-8");
System.out.println("状态2:\r" + status);
} catch (Exception e) {
e.printStackTrace();
}
}
}
签名:
MCwCFBd3DofcDE1aC/KxYxfyKTGv/D19AhQ6K5g5u+0gFAs/BDQx55OnGp/K8g==
状态1:
true
java.security.spec.InvalidKeySpecException: Inappropriate key specification: IOException: algid parse error, not a sequence
at sun.security.provider.DSAKeyFactory.engineGeneratePublic(Unknown Source)
at java.security.KeyFactory.generatePublic(Unknown Source)
at com.mx.oshop.common.util.encrypt.DSA.verify(DSA.java:104)
at com.mx.oshop.common.util.encrypt.DSA.main(DSA.java:199)