Android HMac Hash getHmac(String[] args, String key)

Description

get Hmac

Parameter

Parameter	Description
args	a parameter
key	a parameter

Declaration

public static String getHmac(String[] args, String key) 

Method Source Code

//package com.java2s;
import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;

public class Main {
    private static String encodingCharset = "UTF-8";

    /**/* w  ww  .  j a v  a 2s.c om*/
     * 
     * @param args
     * @param key
     * @return
     */
    public static String getHmac(String[] args, String key) {
        if (args == null || args.length == 0) {
            return (null);
        }
        StringBuffer str = new StringBuffer();
        for (int i = 0; i < args.length; i++) {
            str.append(args[i]);
        }
        return (hmacSign(str.toString(), key));
    }

    /**
     * @param aValue
     * @param aKey
     * @return
     */
    public static String hmacSign(String aValue, String aKey) {
        byte k_ipad[] = new byte[64];
        byte k_opad[] = new byte[64];
        byte keyb[];
        byte value[];
        try {
            keyb = aKey.getBytes(encodingCharset);
            value = aValue.getBytes(encodingCharset);
        } catch (UnsupportedEncodingException e) {
            keyb = aKey.getBytes();
            value = aValue.getBytes();
        }

        Arrays.fill(k_ipad, keyb.length, 64, (byte) 54);
        Arrays.fill(k_opad, keyb.length, 64, (byte) 92);
        for (int i = 0; i < keyb.length; i++) {
            k_ipad[i] = (byte) (keyb[i] ^ 0x36);
            k_opad[i] = (byte) (keyb[i] ^ 0x5c);
        }

        MessageDigest md = null;
        try {
            md = MessageDigest.getInstance("MD5");
        } catch (NoSuchAlgorithmException e) {

            return null;
        }
        md.update(k_ipad);
        md.update(value);
        byte dg[] = md.digest();
        md.reset();
        md.update(k_opad);
        md.update(dg, 0, 16);
        dg = md.digest();
        return toHex(dg);
    }

    /**
     * @param aValue
     * @return
     */
    public static String digest(String aValue) {
        aValue = aValue.trim();
        byte value[];
        try {
            value = aValue.getBytes(encodingCharset);
        } catch (UnsupportedEncodingException e) {
            value = aValue.getBytes();
        }
        MessageDigest md = null;
        try {
            md = MessageDigest.getInstance("SHA");
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
            return null;
        }
        return toHex(md.digest(value));

    }

    public static String toHex(byte input[]) {
        if (input == null)
            return null;
        StringBuffer output = new StringBuffer(input.length * 2);
        for (int i = 0; i < input.length; i++) {
            int current = input[i] & 0xff;
            if (current < 16)
                output.append("0");
            output.append(Integer.toString(current, 16));
        }

        return output.toString();
    }
}

Related

1. derivePKCS5S2Helper(Mac hMac, byte[] P, byte[] S, int c, byte[] iBuf, byte[] out, int outOff)
2. hmacSign(String aValue, String aKey)