Adding Built-In Crypto Library

2026-04-23 00:00:09 +08:00 · 2010-02-24 16:18:35 -08:00
parent c4ac7e5383
commit cb90852dfc
3 changed files with 138 additions and 3 deletions
@@ -0,0 +1,96 @@
+/*
+ * Code originally found on Android Snippets
+ * Contributed to snippets Ferenc Hechler
+ * Copyright (c) 2009 Ferenc Hechler
+ */
+
+package com.phonegap;
+
+import java.security.SecureRandom;
+
+import javax.crypto.Cipher;
+import javax.crypto.KeyGenerator;
+import javax.crypto.SecretKey;
+import javax.crypto.spec.SecretKeySpec;
+
+public class SimpleCrypto {
+	
+	public static String encrypt(String seed, String cleartext) throws Exception {
+		byte[] rawKey = getRawKey(seed.getBytes());
+		byte[] result = encrypt(rawKey, cleartext.getBytes());
+		return toHex(result);
+	}
+	
+	public static String decrypt(String seed, String encrypted) throws Exception {
+		byte [] rawKey = getRawKey(seed.getBytes());
+		byte [] enc = toByte(encrypted);
+		byte [] result = decrypt(rawKey, enc);
+		return new String(result);
+	}
+	
+	public static byte[] getRawKey(byte [] seed) throws Exception {
+		KeyGenerator kgen = KeyGenerator.getInstance("AES");
+		SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
+		sr.setSeed(seed);
+		kgen.init(128, sr);
+		SecretKey skey = kgen.generateKey();
+		byte[] raw = skey.getEncoded();
+		return raw;
+	}
+	
+	private static byte[] encrypt(byte[] raw, byte[] clear) throws Exception {
+		SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
+		Cipher cipher = Cipher.getInstance("AES");
+		cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
+		byte[] encrypted = cipher.doFinal(clear);
+		return encrypted;
+	}
+	
+	private static byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception {
+		SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
+		Cipher cipher = Cipher.getInstance("AES");
+		cipher.init(Cipher.DECRYPT_MODE, skeySpec);
+		byte[] decrypted = cipher.doFinal(encrypted);
+		return decrypted;
+	}
+	
+	public static String toHex(String txt)
+	{
+		return toHex(txt.getBytes());
+	}
+	
+	public static String fromHex(String hex)
+	{
+		return new String(toByte(hex));
+	}
+	
+	public static byte[] toByte(String hexString) {
+		int len = hexString.length()/2;
+		byte[] result = new byte[len];
+		for (int i = 0; i < len; ++i)
+		{
+			result[i] = Integer.valueOf(hexString.substring(2*i, 2*i+2), 16).byteValue();
+		}
+		return result;
+	}
+	
+	public static String toHex(byte[] buf) {
+		if (buf == null)
+		{
+			return "";
+		}
+		StringBuffer result = new StringBuffer(2*buf.length);
+		for (int i = 0; i < buf.length; i++)
+		{
+			appendHex(result, buf[i]);
+		}
+		return result.toString();
+	}
+	
+	private final static String HEX = "01234567890ABCDEF";
+	
+	private static void appendHex(StringBuffer sb, byte b)
+	{
+		sb.append(HEX.charAt((b>>4)&0x0f)).append(HEX.charAt(b&0x0f));
+	}
+}