I am compressing a Serializable Object using following snippet:
private byte[] compressObject(Object obj) throws IOException {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
GZIPOutputStream gzipOut = new GZIPOutputStream(baos);
ObjectOutputStream objectOut = new ObjectOutputStream(gzipOut);
objectOut.writeObject(obj);
objectOut.close();
byte[] bytes = baos.toByteArray();
return bytes;
}
And decompressing the same object using following snippet:
private Object decompressObject(byte[] bytes) throws IOException,ClassNotFoundException {
ByteArrayInputStream bais = new ByteArrayInputStream(bytes);
GZIPInputStream gzipIn = new GZIPInputStream(bais);
ObjectInputStream objectIn = new ObjectInputStream(gzipIn);
Object obj = objectIn.readObject();
objectIn.close();
return obj;
}
Before compressing the Object and after decompressing the Object, I calculate the MD5 Hash using following snippet:
public String getMD5Hash(Object obj) throws IOException, NoSuchAlgorithmException {
ByteArrayOutputStream bos = new ByteArrayOutputStream();
ObjectOutput out = new ObjectOutputStream(bos);
out.writeObject(obj);
byte[] data = bos.toByteArray();
MessageDigest m = MessageDigest.getInstance("MD5");
m.update(data,0,data.length);
BigInteger i = new BigInteger(1,m.digest());
return String.format("%1$032X", i);
}
But the MD5 Hash calculated before compression and after compression does not match. Kindly suggest how to get the Object as it is after decompression.
Thanks.
You probably need to use the finish method on the GZIPOutputStream to get it to compress the data.
Related
I have created an Encryption method to encrypt the data into test.txt Text file. The encryption is Working fine and its Reading the encryted text file into textBox1.
I m using 2 buttons and 2 textBox for doing this.
Now I want to Read the decryption text from test.txt in textBox2
but when i click on the button to read data from test.txt to textBox2.
I am getting an exception like (CryptographicException was unhandled) Bad Data.
Here is the code I used for Dycryption.
private void button2_Click(object sender, EventArgs e)
{
FileStream stream = new FileStream("C:\\test.txt",
FileMode.Open, FileAccess.Read);
DESCryptoServiceProvider cryptic = new DESCryptoServiceProvider();
cryptic.Key = ASCIIEncoding.ASCII.GetBytes("ABCDEFGH");
cryptic.IV = ASCIIEncoding.ASCII.GetBytes("ABCDEFGH");
CryptoStream crStream = new CryptoStream(stream,
cryptic.CreateDecryptor(), CryptoStreamMode.Read);
StreamReader reader = new StreamReader(crStream);
//string data = reader.ReadToEnd();
textBox2.Text = reader.ReadLine();
//stream.Close();
}
Codes that i used for Encrytion is here:
private void button1_Click(object sender, EventArgs e)
{
FileStream stream = new FileStream("C:\\test.txt", FileMode.OpenOrCreate, FileAccess.Write);
DESCryptoServiceProvider cryptic = new DESCryptoServiceProvider();
cryptic.Key = ASCIIEncoding.ASCII.GetBytes("ABCDEFGH");
cryptic.IV = ASCIIEncoding.ASCII.GetBytes("ABCDEFGH");
CryptoStream crStream = new CryptoStream(stream,
cryptic.CreateEncryptor(), CryptoStreamMode.Write);
byte[] data = ASCIIEncoding.ASCII.GetBytes(textBox2.Text);
crStream.Write(data, 0, data.Length);
crStream.Close();
stream.Close();
string text = System.IO.File.ReadAllText(#"C://test.txt");
textBox1.Text = text.ToString();
}
I don't know why you want to read it from test.txt file. when your displaying it in textbox. but check below code you can able to encrypt and decry-pt and meanwhile able to display and save in text boxes.
protected void Button1_Click(object sender, EventArgs e)
{
FileStream stream = new FileStream("C:\\test.txt", FileMode.OpenOrCreate, FileAccess.Write);
string datastring= Encrypt("ABCDEFGH", "ABCDEFGH");
byte[] data = ASCIIEncoding.ASCII.GetBytes(datastring);
stream.Write(data, 0, data.Length);
stream.Close();
string text = System.IO.File.ReadAllText(#"C:\\test.txt");
TextBox1.Text = text.ToString();
}
protected void Button2_Click(object sender, EventArgs e)
{
StreamReader reader =null;
try
{
FileStream stream = new FileStream("C:\\test.txt",
FileMode.Open, FileAccess.Read);
string fileContents;
using ( reader = new StreamReader(stream))
{
fileContents = reader.ReadToEnd();
}
string data = Decrypt(fileContents, "ABCDEFGH");
TextBox2.Text = data;
stream.WriteByte(Convert.ToByte(data));
stream.Close();
}
catch (Exception ex)
{
}
finally
{
reader.Close();
}
}
public static string Encrypt(string message, string password)
{
// Encode message and password
byte[] messageBytes = ASCIIEncoding.ASCII.GetBytes(message);
byte[] passwordBytes = ASCIIEncoding.ASCII.GetBytes(password);
// Set encryption settings -- Use password for both key and init. vector
DESCryptoServiceProvider provider = new DESCryptoServiceProvider();
ICryptoTransform transform = provider.CreateEncryptor(passwordBytes, passwordBytes);
CryptoStreamMode mode = CryptoStreamMode.Write;
// Set up streams and encrypt
MemoryStream memStream = new MemoryStream();
CryptoStream cryptoStream = new CryptoStream(memStream, transform, mode);
cryptoStream.Write(messageBytes, 0, messageBytes.Length);
cryptoStream.FlushFinalBlock();
// Read the encrypted message from the memory stream
byte[] encryptedMessageBytes = new byte[memStream.Length];
memStream.Position = 0;
memStream.Read(encryptedMessageBytes, 0, encryptedMessageBytes.Length);
// Encode the encrypted message as base64 string
string encryptedMessage = Convert.ToBase64String(encryptedMessageBytes);
return encryptedMessage;
}
public static string Decrypt(string encryptedMessage, string password)
{
// Convert encrypted message and password to bytes
byte[] encryptedMessageBytes = Convert.FromBase64String(encryptedMessage);
byte[] passwordBytes = ASCIIEncoding.ASCII.GetBytes(password);
// Set encryption settings -- Use password for both key and init. vector
DESCryptoServiceProvider provider = new DESCryptoServiceProvider();
ICryptoTransform transform = provider.CreateDecryptor(passwordBytes, passwordBytes);
CryptoStreamMode mode = CryptoStreamMode.Write;
// Set up streams and decrypt
MemoryStream memStream = new MemoryStream();
CryptoStream cryptoStream = new CryptoStream(memStream, transform, mode);
cryptoStream.Write(encryptedMessageBytes, 0, encryptedMessageBytes.Length);
cryptoStream.FlushFinalBlock();
// Read decrypted message from memory stream
byte[] decryptedMessageBytes = new byte[memStream.Length];
memStream.Position = 0;
memStream.Read(decryptedMessageBytes, 0, decryptedMessageBytes.Length);
// Encode deencrypted binary data to base64 string
string message = ASCIIEncoding.ASCII.GetString(decryptedMessageBytes);
return message;
}
I am trying to zip a 30Mb excel file.
Wrapping th fileinputstream and fileoutputstream reduced some of the memory consumption.
Please suggest if you have a better option than this approach.
Do you think, flushing the ZipOutputStream after zos.write() inside while loop will be of any advantage?
Following is the code which i use.
public void zipBigFile()
throws IOException, ParseException {
String outFileName= "D:/Out/Big.zip";
File file = new File(outFileName);
FileOutputStream out = new FileOutputStream(file);
ZipOutputStream zos = new ZipOutputStream(new BufferedOutputStream(out));
byte[] buffer = new byte[1024 * 8];
String inFileName = "D:/In/Big_File.xlsx";
FileInputStream fis = new FileInputStream(inFileName);
BufferedInputStream bis = new BufferedInputStream(fis);
ZipEntry zipEntry = new ZipEntry("Big_File_Zipped.xlsx");
zos.putNextEntry(zipEntry);
int length;
while ((length = bis.read(buffer)) > 0) {
zos.write(buffer, 0, length);
}
zos.closeEntry();
fis.close();
fis = null;
buffer = null;
zos.flush();
zos.close();
out.close();
out = null;
zos = null;
}
hey every one this is my decryption code i want to decrypt this password but problem is that its gives an error
static void Main(string[] args)
{
string str = Decrypt("vASqxLq4dmegE0l3K8T7ng==", "");
Console.WriteLine(str);
Console.ReadKey();
}
private const string IV = "MazenTech.com.pk";
private const int keysize = 128;
public static string Decrypt(string cipherText, string passPhrase)
{
byte[] plainTextBytes = null;
int decryptedByteCount = 0;
try
{
byte[] IVBytes = Encoding.ASCII.GetBytes(IV);
byte[] cipherTextBytes = Convert.FromBase64String(cipherText);
PasswordDeriveBytes password = new PasswordDeriveBytes(passPhrase, null);
byte[] keyBytes = password.GetBytes(keysize / 8);
RijndaelManaged symmetricKey = new RijndaelManaged();
symmetricKey.Mode = CipherMode.CBC;
ICryptoTransform decryptor = symmetricKey.CreateDecryptor(keyBytes, IVBytes);
MemoryStream memoryStream = new MemoryStream(cipherTextBytes);
CryptoStream cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read);
plainTextBytes = new byte[cipherTextBytes.Length];
decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length); // error this line
memoryStream.Close();
cryptoStream.Close();
}
catch (Exception ex)
{
Console.WriteLine("Your Password is Incorrect....");
}
return Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount);
}
how to fix it please help me.
Try it by setting PeddingMode property.
RijndaelManaged symmetricKey = new RijndaelManaged();
symmetricKey.Mode = CipherMode.CBC;
symmetricKey.Padding = PaddingMode.None;
node js code：
function AES_encrypt(){
var bKey = new Buffer('24Qn9974h50D9DNi', 'utf-8');
var bInput = new Buffer(‘test’, 'utf-8');
console.log(bKey.length);
var cipher = crypto.createCipher('AES-128-ECB',bKey);
//cipher.setAutoPadding(auto_padding=false);
var crypted = cipher.update(bInput,null,'base64');
crypted+=cipher.final('base64');
console.log(crypted);
return crypted;
}
get Result：57b6b7oulw7eO5h7efZ9/w==
java code：
main java：
String data = AES.encryptToBase64("test","24Qn9974h50D9DNi");
AES java：
public static String encryptToBase64(String data, String key){
try {
byte[] valueByte = encrypt(data.getBytes("utf-8"), key.getBytes("utf-8");
return new String(Base64.encode(valueByte));
} catch (UnsupportedEncodingException e) {
throw new RuntimeException("encrypt fail!", e);
}
}
public static byte[] encrypt(byte[] data, byte[] key) {
if(key.length!=16){
throw new RuntimeException("Invalid AES key length (must be 16 bytes)");
}
try {
SecretKeySpec secretKey = new SecretKeySpec(key, "AES");
byte[] enCodeFormat = secretKey.getEncoded();
SecretKeySpec seckey = new SecretKeySpec(enCodeFormat,"AES");
Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, seckey);// 初始化
byte[] result = cipher.doFinal(data);
return result; // 加密
} catch (Exception e){
throw new RuntimeException("encrypt fail!", e);
}
}
get Result：wA1JU6VxMaVl8Ck8pBrX8A==
Use crypto.createCipheriv to solve the issue,
http://nodejs.org/api/crypto.html#crypto_crypto_createcipheriv_algorithm_key_iv
You need to pad the string "test" to 16 bytes. I believe Java uses PKCS padding by default (but there are other padding schemes, too).
String data = AES.encryptToBase64("test","24Qn9974h50D9DNi");
I am working on implementing a SAMLSLO through HTTP-REDIRECT binding mechanism. Using deflate-inflate tools gives me a DataFormatException with incorrect header check.
I tried this as a stand-alone. Though I did not get DataFormatException here I observed the whole message is not being returned.
import java.io.UnsupportedEncodingException;
import java.util.logging.Level;
import java.util.zip.DataFormatException;
import java.util.zip.Deflater;
import java.util.zip.Inflater;
public class InflateDeflate {
public static void main(String[] args) {
String source = "This is the SAML String";
String outcome=null;
byte[] bytesource = null;
try {
bytesource = source.getBytes("UTF-8");
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
int byteLength = bytesource.length;
Deflater compresser = new Deflater();
compresser.setInput(bytesource);
compresser.finish();
byte[] output = new byte[byteLength];
int compressedDataLength = compresser.deflate(output);
outcome = new String(output);
String trimmedoutcome = outcome.trim();
//String trimmedoutcome = outcome; // behaves the same way as trimmed;
// Now try to inflate it
Inflater decompresser = new Inflater();
decompresser.setInput(trimmedoutcome.getBytes());
byte[] result = new byte[4096];
int resultLength = 0;
try {
resultLength = decompresser.inflate(result);
} catch (DataFormatException e) {
e.printStackTrace();
}
decompresser.end();
System.out.println("result length ["+resultLength+"]");
String outputString = null;
outputString = new String(result, 0, resultLength);
String returndoc = outputString;
System.out.println(returndoc);
}
}
Surprisingly I get the result as [22] bytes, the original is [23] bytes and the 'g' is missing after inflating.
Am I doing something fundamentally wrong here?
Java's String is a CharacterSequence (a character is 2 bytes). Using new String(byte[]) may not correctly convert your byte[] to a String representation. At least you should specify a character encoding new String(byte[], "UTF-8") to prevent invalid character conversions.
Here's an example of compressing and decompressing:
import java.util.zip.Deflater;
import java.util.zip.InflaterInputStream;
...
byte[] sourceData; // bytes to compress (reuse byte[] for compressed data)
String filename; // where to write
{
// compress the data
Deflater deflater = new Deflater(Deflater.DEFAULT_COMPRESSION);
deflater.setInput(sourceData);
deflater.finish();
int compressedSize = deflater.deflate(data, 0, sourceData.length, Deflater.FULL_FLUSH);
// write the data
OutputStream stream = new FileOutputStream(filename);
stream.write(data, 0, compressedSize);
stream.close();
}
{
byte[] uncompressedData = new byte[1024]; // where to store the data
// read the data
InputStream stream = new InflaterInputStream(new FileInputStream(filename));
// read data - note: may not read fully (or evenly), read from stream until len==0
int len, offset = 0;
while ((len = stream.read(uncompressedData , offset, uncompressedData .length-offset))>0) {
offset += len;
}
stream.close();
}