Java md5，PHP方式

Question

I have been working on this for hours, but I can't get it to work.

Basically I am developing a REST client in Java for a REST server in PHP. Both the client and the server have to compute the md5 of a string and the server will compare them for authentication (kinda).

On the server, the PHP code is:

md5("getTokenapi_keybf8ddfs845jhre980543jhsjfro93fd8capi_ver1tokeniud9ER£jdfff");

that generates:

4d7b2e42c3dfd11de3e77b9fe2211b87

Nice!

Here is the code for the client:

import java.security.*;
....
String s = "getTokenapi_keybf8ddfs845jhre980543jhsjfro93fd8capi_ver1tokeniud9ER£jdfff";
byte[] bytesOfMessage = s.getBytes("UTF-8");
MessageDigest md = MessageDigest.getInstance("MD5");
byte[] thedigest = md.digest(bytesOfMessage);    

System.out.println("String2: " + thedigest);        
System.out.println("String3: " + new String(thedigest));

That generates:

String2: [B@42e816
String3: M{.B�����{��!�

How can I get Java to compute the md5 sum the same way PHP does, please?

Thanks, Dan

Answer 1

Give this a try:

public static String md5(String input) throws NoSuchAlgorithmException {
    String result = input;
    if(input != null) {
        MessageDigest md = MessageDigest.getInstance("MD5"); //or "SHA-1"
        md.update(input.getBytes());
        BigInteger hash = new BigInteger(1, md.digest());
        result = hash.toString(16);
        while(result.length() < 32) { //40 for SHA-1
            result = "0" + result;
        }
    }
    return result;
}

code from http://web.archive.org/web/20140209230440/http://www.sergiy.ca/how-to-make-java-md5-and-sha-1-hashes-compatible-with-php-or-mysql/

Answer 2

Found myself:

import java.math.BigInteger;
..
public static String md5(String input) throws NoSuchAlgorithmException {
        String result = input;
        if(input != null) {
            MessageDigest md = MessageDigest.getInstance("MD5"); //or "SHA-1"
            md.update(input.getBytes());
            BigInteger hash = new BigInteger(1, md.digest());
            result = hash.toString(16);
            if ((result.length() % 2) != 0) {
                result = "0" + result;
            }
        }
        return result;
    }

Source: http://www.sergiy.ca/how-to-make-java-md5-and-sha-1-hashes-compatible-with-php-or-mysql/

Answer 3

You are outputting the raw md5 output, which is just a bunch of bytes. You would get the same result in php if you said md5("some string", true).

You need to convert the bytes to ascii characters instead.

Answer 4

if you use spring security framework , just do :

import org.springframework.security.authentication.encoding.*

new Md5PasswordEncoder().encodePassword("myWord",null)

The same result as PHP::md5() . I confirm

See more examples

Answer 5

You need to convert the result into the HEX representation. This is how it is done in Fast MD5 library :

    private static final char[] HEX_CHARS = { '0', '1', '2', '3', '4', '5',
            '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f', };

    /**
     * Turns array of bytes into string representing each byte as unsigned hex
     * number.
     * 
     * @param hash
     *            Array of bytes to convert to hex-string
     * @return Generated hex string
     */
    public static String asHex(byte hash[]) {
        char buf[] = new char[hash.length * 2];
        for (int i = 0, x = 0; i < hash.length; i++) {
            buf[x++] = HEX_CHARS[(hash[i] >>> 4) & 0xf];
            buf[x++] = HEX_CHARS[hash[i] & 0xf];
        }
        return new String(buf);
    }

So you will need to call System.out.println("String3: " + asHex(thedigest));