I've never worked with encryption before. Actually I know nothing about encryption. I have a file encrypted with openssl tool using params:
openssl aes-256-cbc -nosalt -in fileIn -out fileOUT -p -k KEY
I need to decrypt it into memory but I don't know how. Can anyone provide me the code related to encryption?
Here's class I have written to decrypt a string encoded with params above (if I remmeber it correct):
public class CipherUtils {
public static byte[] getKey(String password, byte[] salt) {
try {
byte[] passwordSalt = EncodingUtils.getAsciiBytes(password);
passwordSalt = concatenateByteArrays(passwordSalt, salt);
byte[] hash1 = getHashForHash(null, passwordSalt);
byte[] hash2 = getHashForHash(hash1, passwordSalt);
byte[] key = concatenateByteArrays(hash1, hash2);
return key;
} catch (Exception e) {
return null;
}
}
public static byte[] getIV(String password, byte[] salt) {
try {
byte[] passwordSalt = EncodingUtils.getAsciiBytes(password);
passwordSalt = concatenateByteArrays(passwordSalt, salt);
byte[] hash1 = getHashForHash(null, passwordSalt);
byte[] hash2 = getHashForHash(hash1, passwordSalt);
byte[] hash3 = getHashForHash(hash2, passwordSalt);
return hash3;
} catch (Exception e) {
return null;
}
}
private static byte[] getHashForHash(byte[] hash, byte[] passwordSalt) {
try {
byte[] hashMaterial = concatenateByteArrays(hash, passwordSalt);
MessageDigest md = MessageDigest.getInstance("MD5");
return md.digest(hashMaterial);
} catch (Exception e) {
return null;
}
}
private static byte[] concatenateByteArrays(byte[] a, byte[] b) {
if (a == null)
return b;
if (b == null)
return a;
byte[] result = new byte[a.length + b.length];
System.arraycopy(a, 0, result, 0, a.length);
System.arraycopy(b, 0, result, a.length, b.length);
return result;
}
}
Salt is an empty bytearray in this case. It uses apache-commons-compress.jar.
Here's usage example:
byte[] key = CipherUtils.getKey(password, null);
byte[] IV = CipherUtils.getIV(password, null);
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE, new SecretKeySpec(key, "AES"),
new IvParameterSpec(IV));
cis = new CipherInputStream(is, cipher);
Where is is an InputStream of encrypted data.
this may helps you
public void encrypt() throws IOException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException {
// Here you read the cleartext.
FileInputStream fis = new FileInputStream("data/cleartext");
// This stream write the encrypted text. This stream will be wrapped by
// another stream.
FileOutputStream fos = new FileOutputStream("data/encrypted");
// Length is 16 byte
SecretKeySpec sks = new SecretKeySpec("yourkey".getBytes(), "AES");
// Create cipher
Cipher cipher = Cipher.getInstance("AES/CBC");
cipher.init(Cipher.ENCRYPT_MODE, sks);
// Wrap the output stream
CipherOutputStream cos = new CipherOutputStream(fos, cipher);
// Write bytes
int b;
byte[] d = new byte[8];
while ((b = fis.read(d)) != -1) {
cos.write(d, 0, b);
}
// Flush and close streams.
cos.flush();
cos.close();
fis.close();
}
Decrypt
public void decrypt() throws IOException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException {
FileInputStream fis = new FileInputStream("data/encrypted");
FileOutputStream fos = new FileOutputStream("data/decrypted");
SecretKeySpec sks = new SecretKeySpec("yourkey".getBytes(), "AES");
Cipher cipher = Cipher.getInstance("AES/CBC");
cipher.init(Cipher.DECRYPT_MODE, sks);
CipherInputStream cis = new CipherInputStream(fis, cipher);
int b;
byte[] d = new byte[8];
while((b = cis.read(d)) != -1) {
fos.write(d, 0, b);
}
fos.flush();
fos.close();
cis.close();
}
