Java中消息摘要的编程(MD5/SHA/HMAC)的使用

迈不过友情╰ 2022-07-16 10:24 105阅读 0赞

主类：

/**
     * Created by cuboo on 2016/10/14.
     */
    public class Main {
        public static void main(String agrs[]) throws Exception {
            //String keyType = "MD5";
           // String keyType = "SHA-1"/SHA-256/SHA-384/SHA-512
    //        byte[] data = "abcdefg".getBytes();
    //        byte[] encryptData = Messagedigest.getMD5ofFile("text.txt",keyType);
    
    
            //HMAC算法的编程使用
    //        String keyType = "HmacMD5";//HmacMD5/HmacSHA1/HmacSHA256/HmacSHA384/HmacSHA512
    //
    //        byte[] data = "abcdefg".getBytes();
    //        byte[] key = Messagedigest.InitKey(keyType);
    //        byte[] encryptData = Messagedigest.encrypt(key,keyType,data);
    //
    //        System.out.println(bytesToHexString(key));
    //        System.out.println(fromBytesToHexString(encryptData));
    
        }
    
        public static String bytesToHexString(byte[] data){
            StringBuilder strb = new StringBuilder();
            for (int i = 0; i < data.length; i++) {
                String str = Integer.toHexString(data[i] & 0xFF);
                 if (str.length() == 1){
                     strb.append(0).append(str);
                 }else {
                     strb.append(str);
                 }
    
            }
            return strb.toString();
        }
    
        public static String fromBytesToHexString(byte[] data){
            StringBuilder str = new StringBuilder();
            for (int i = 0; i < data.length; i++) {
                 String s = Integer.toHexString(0xFF & data[i]);
                if (s.length() == 1){
                    str.append(0).append(s);
                }else {
                    str.append(s);
                }
            }
            return str.toString();
        }
    
        public static String fromHexStringToString(String str){
            char[] c = str.toCharArray();
            StringBuilder builder = new StringBuilder();
            for (int i = 0; i < c.length-1; i+=2) {
                 int num = (c[i]-'0')*16+(c[i+1]-'0')*1;
                 builder.append((char) num);
            }
            return builder.toString();
        }
    
    }

方法类：

import javax.crypto.KeyGenerator;
    import javax.crypto.Mac;
    import javax.crypto.SecretKey;
    import javax.crypto.spec.SecretKeySpec;
    import java.io.FileInputStream;
    import java.io.FileNotFoundException;
    import java.security.DigestInputStream;
    import java.security.MessageDigest;
    
    /**
     * Created by cuboo on 2016/10/14.
     */
    public class Messagedigest {
    
        //获得byte数组的MD5/SHA
        public static byte[] encryptMD5(byte[] data,String codeType) throws Exception {
            MessageDigest md5 = MessageDigest.getInstance(codeType);
            md5.update(data);
           return md5.digest();
        }
        //获得文件的MD5/SHA
        public static byte[] getMD5ofFile(String path,String codeType) throws Exception {
            FileInputStream fis = new FileInputStream(path);
            DigestInputStream dis = new DigestInputStream(fis,MessageDigest.getInstance(codeType));
            byte[] buffer = new byte[1024];
            int reader = dis.read(buffer);
            if (reader != 1){
                reader = dis.read(buffer);
            }
            MessageDigest md5 = dis.getMessageDigest();
            return md5.digest();
        }
    
        /*
         *生成秘钥
         */
        public static byte[] InitKey(String keyType) throws Exception {
            KeyGenerator keyGenerator = KeyGenerator.getInstance(keyType);
            SecretKey secretKey = keyGenerator.generateKey();
            return  secretKey.getEncoded();
        }
        /*
         *加密
         */
        public static byte[] encrypt(byte[] key,String keyType,byte[] data)
                throws Exception {
            SecretKey secretKey = new SecretKeySpec(key,keyType);
            Mac mac = Mac.getInstance(keyType);
            mac.init(secretKey);
            return mac.doFinal(data);
        }
    
    }