Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;

import android.util.Log;
import java.io.UnsupportedEncodingException;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import javax.crypto.spec.SecretKeySpec;

public class Main {
    private static final String TAG = "AESUtils";
    private static final String HASH_ALGORITHM = "SHA-256";
    public static boolean DEBUG_LOG_ENABLED = false;

    /**
     * Generates SHA256 hash of the password which is used as key
     *
     * @param password used to generated key
     * @return SHA256 of the password
     */
    private static SecretKeySpec generateKey(final String password)
            throws NoSuchAlgorithmException, UnsupportedEncodingException {
        final MessageDigest digest = MessageDigest.getInstance(HASH_ALGORITHM);
        byte[] bytes = password.getBytes("UTF-8");
        digest.update(bytes, 0, bytes.length);
        byte[] key = digest.digest();

        log("SHA-256 key ", key);

        SecretKeySpec secretKeySpec = new SecretKeySpec(key, "AES");
        return secretKeySpec;
    }

    private static void log(String what, byte[] bytes) {
        if (DEBUG_LOG_ENABLED)
            Log.d(TAG, what + "[" + bytes.length + "] [" + bytesToHex(bytes) + "]");
    }

    private static void log(String what, String value) {
        if (DEBUG_LOG_ENABLED)
            Log.d(TAG, what + "[" + value.length() + "] [" + value + "]");
    }

    /**
     * Converts byte array to hexidecimal useful for logging and fault finding
     *
     * @param bytes
     * @return
     */
    private static String bytesToHex(byte[] bytes) {
        final char[] hexArray = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
        char[] hexChars = new char[bytes.length * 2];
        int v;
        for (int j = 0; j < bytes.length; j++) {
            v = bytes[j] & 0xFF;
            hexChars[j * 2] = hexArray[v >>> 4];
            hexChars[j * 2 + 1] = hexArray[v & 0x0F];
        }
        return new String(hexChars);
    }
}