我必须使用加密/解密机制来进行j2me应用程序和大量搜索我发现Bouncy Castle最适合j2me应用程序。
以下是我执行加密所遵循的步骤:
以下是示例代码。它使用密钥和IV(初始化向量)进行加密密钥生成。是否与sha256哈希相同?
static String strEnc = "String for encryption";
final static String strPassword = "2345678978787878"; // AES 128 -
String encrypted;
public static String strEncResult;
public static String strDcrResult;
public static String keyStr;
String dcrtpt;
String enc1;
//Key key;
/*public static byte[] getSHA256(String key) {
SHA256Digest digester = new SHA256Digest();
byte[] retValue = new byte[digester.getDigestSize()];
digester.update(key.getBytes(), 0, key.length());
digester.doFinal(retValue, 0);
System.out.println("retValue === "+retValue);
return retValue;
}*/
public static byte[] cipherData(PaddedBufferedBlockCipher cipher,
byte[] data) throws Exception {
int minSize = cipher.getOutputSize(data.length);
byte[] outBuf = new byte[minSize];
int length1 = cipher.processBytes(data, 0, data.length, outBuf, 0);
int length2 = cipher.doFinal(outBuf, length1);
int actualLength = length1 + length2;
byte[] result = new byte[actualLength];
System.arraycopy(outBuf, 0, result, 0, result.length);
return result;
}
public static byte[] decrypt(byte[] cipher, byte[] key, byte[] iv)
throws Exception {
PaddedBufferedBlockCipher aes = new PaddedBufferedBlockCipher(
new CBCBlockCipher(new AESEngine()));
CipherParameters ivAndKey = new ParametersWithIV(new KeyParameter(key),
iv);
aes.init(false, ivAndKey);
return cipherData(aes, cipher);
}
public static byte[] encrypt(byte[] plain, byte[] key, byte[] iv)
throws Exception {
PaddedBufferedBlockCipher aes = new PaddedBufferedBlockCipher(
new CBCBlockCipher(new AESEngine()));
CipherParameters ivAndKey = new ParametersWithIV(new KeyParameter(key),
iv);
aes.init(true, ivAndKey);
return cipherData(aes, plain);
}
public static String encryptMe(String plain){
byte[] plainStr = plain.getBytes();
byte[] keyStr = strPassword.getBytes();//getSHA256(strPassword);
byte[] ivStr = strPassword.getBytes();//getSHA256(strPassword);
try {
byte[] encBytes = encrypt(plainStr, keyStr,
ivStr);
byte[] encbase = Base64.encode(encBytes);
strEncResult = new String(encbase, "UTF-8");
} catch (Exception e) {
e.printStackTrace();
}
return strEncResult;
}
public static String decryptMe(String encrtptedStr){
try {
byte[] dcrByte = Base64.decode(encrtptedStr.getBytes());
byte[] dec = decrypt(dcrByte, strPassword.getBytes()/*getSHA256(strPassword)*/,
strPassword.getBytes()/*getSHA256(strPassword)*/);
strDcrResult = new String(dec, "UTF-8");
} catch (Exception e) {
e.printStackTrace();
}
return strDcrResult;
}
protected void destroyApp(boolean unconditional)
throws MIDletStateChangeException {
}
protected void pauseApp() {
}
protected void startApp() throws MIDletStateChangeException {
byte[] enc;
try {
enc = encrypt(strEnc.getBytes(), /*getSHA256(strPassword)*/strPassword.getBytes(),
/*getSHA256(strPassword)*/strPassword.getBytes());
byte[] encbase = Base64.encode(enc);
encrypted = new String(encbase, "UTF-8");
enc1= encryptMe ("String for encryption");
System.out.println("Encrypted is:" + encbase + "/// "+enc1);
} catch (Exception e) {
e.printStackTrace();
}
byte[] decbase = Base64.decode(encrypted.getBytes());
byte[] dec;
try {
dec = decrypt(decbase, /*getSHA256(strPassword)*/strPassword.getBytes(),
/*getSHA256(strPassword)*/strPassword.getBytes());
dcrtpt = decryptMe(enc1);
System.out.println("Decrypted file is:" + new String(dec, "UTF-8")+"///"+dcrtpt);
} catch (Exception e) {
e.printStackTrace();
}
}
答案 0 :(得分:0)
我搞定了!!我使用 sha256 进行密钥生成,并使用第一个 16位进行AES 128加密。当它是16或16以下的字符串时,我得到正确的加密和解密数据。如果它超过16个字符串我得到16个字符与一些不需要的字符。 (例如:abcdefghijklmnop5 @ D ! &M \〜C )任何人都可以帮我解决这个问题。请参阅下面的代码
public static String getSHA256(String key) {
SHA256Digest digester = new SHA256Digest();
byte[] retValue = new byte[digester.getDigestSize()];
digester.update(key.getBytes(), 0, key.length());
digester.doFinal(retValue,0);
byteToStr = new String(Hex.encode(retValue));
System.out.println("byteToStr === " + byteToStr);
byteToStr = byteToStr.substring(0, 16);
System.out.println("byteToStr after subString === " + byteToStr);
return byteToStr;
}
public static byte[] cipherData(BufferedBlockCipher cipher, byte[] data)
throws Exception {
int minSize = cipher.getOutputSize(data.length);
System.out.println("min Size = "+minSize);
byte[] outBuf = new byte[minSize];
int length1 = cipher.processBytes(data, 0, data.length, outBuf, 0);
int length2 = cipher.doFinal(outBuf, length1);
System.out.println("length1 = "+length1 +"/ length2 = "+length2);
int actualLength = length1 + length2;
System.out.println("actualLength = "+actualLength);
byte[] result = new byte[actualLength];
System.arraycopy(outBuf, 0, result, 0, result.length);
return result;
}
public static byte[] decrypt(byte[] cipher, byte[] key/* , byte[] iv */)
throws Exception {
/*
* PaddedBufferedBlockCipher aes = new PaddedBufferedBlockCipher( new
* CBCBlockCipher(new AESEngine())); CipherParameters ivAndKey = new
* ParametersWithIV(new KeyParameter(key), iv); aes.init(false,
* ivAndKey); return cipherData(aes, cipher);
*/
BufferedBlockCipher aes = new PaddedBufferedBlockCipher(
new CBCBlockCipher(new AESEngine()));
KeyParameter secretKey = new KeyParameter(key);
aes.init(false, secretKey);
return cipherData(aes, cipher);
}
public static byte[] encrypt(byte[] plain, byte[] key/* , byte[] iv */)
throws Exception {
/*
* PaddedBufferedBlockCipher aes = new PaddedBufferedBlockCipher( new
* CBCBlockCipher(new AESEngine())); CipherParameters ivAndKey = new
* ParametersWithIV(new KeyParameter(key), iv);
*/
BufferedBlockCipher aes = new PaddedBufferedBlockCipher(
new CBCBlockCipher(new AESEngine()));
KeyParameter secretKey = new KeyParameter(key);
aes.init(true, secretKey);
return cipherData(aes, plain);
}
public static String encryptMe(String plain) {
byte[] plainStr = plain.getBytes();
byte[] keyStr = getSHA256(key).getBytes();
// byte[] ivStr = iv.getBytes();//
System.out.println("key str = "+Strings.fromByteArray(keyStr));
try {
byte[] encBytes = encrypt(plainStr, keyStr/*
* , ivStr
*/);
strEncResult= Base64.toBase64String(encBytes);
//strEncResult = new String(encbase);
} catch (Exception e) {
e.printStackTrace();
}
return strEncResult;
}
public static String decryptMe(String cipherText) {
try {
byte[] dcrByte = Base64.decode(cipherText);
byte[] dec = decrypt(dcrByte, getSHA256(key).getBytes()/*
* ,iv.getBytes
* ()
*/);
strDcrResult = Strings.fromByteArray(dec);
} catch (Exception e) {
e.printStackTrace();
}
return strDcrResult;
}