Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
import android.util.Log;

import javax.crypto.Cipher;

public class Main {
    private static final String LOG_TAG = "MarvinMessaging";
    public static Cipher storageEncryptionCipher;

    public static String encryptText(CharSequence plaintext) {
        return encryptText(fromCharSeqToChars(plaintext), storageEncryptionCipher);
    }

    public static String encryptText(char[] plaintext) {
        return encryptText(plaintext, storageEncryptionCipher);
    }

    private static String encryptText(char[] plaintext, Cipher cipher) {
        byte[] plaintextBytes = charArrayToByteArray(plaintext);
        byte[] ciphertext = {};

        try {
            ciphertext = cipher.doFinal(plaintextBytes);
        } catch (Exception e) {
            Log.d(LOG_TAG, "encryptText", e);
        }

        //turn into hex so storage as a string is possible (db)
        return toHexString(ciphertext);
    }

    /** 
     * we can't store a password as a string, since in Java
     * strings are immutable, and thus we can't null out and
     * guarantee the password doesn't hang around after GC;
     * CharSequence doesn't have this problem, and that's what
     * an EditText returns; So, we go from CharSequence to
     * an array of bytes; We want a byte array anyway, for crypto.
     *
     */
    public static char[] fromCharSeqToChars(CharSequence seq) {
        char[] ret = new char[seq.length()];
        int i;

        for (i = 0; i < seq.length(); i++) {
            ret[i] = seq.charAt(i);
        }
        return ret;
    }

    public static byte[] charArrayToByteArray(char[] in) {
        byte[] ret = new byte[in.length];
        int i;
        for (i = 0; i < in.length; i++) {
            ret[i] = (byte) (in[i] & 0xFF);
        }
        return ret;
    }

    public static String toHexString(byte bytes[]) {
        StringBuffer buf = new StringBuffer();
        for (int i = 0; i < bytes.length; ++i) {
            buf.append(Integer.toHexString(0x0100 + (bytes[i] & 0x00FF)).substring(1));
        }
        return buf.toString();
    }
}