Dopo aver letto attraverso suggerimenti Erickson, e il picco di ciò che potevo da un paio di altre pubblicazioni e questo esempio qui, Ho provato ad aggiornare il codice Doug con le modifiche consigliate. Sentiti libero di modificare per fare meglio.
- Il vettore di inizializzazione non è più risolto
- La chiave di crittografia è derivata dall’uso di Erickson Code
- 8 Il byte salato è generato in SetSecright () utilizzando Secuurendom ()
- La chiave di decrittografia viene generata dalla crittografia del sale e della password
- La crittografia decrittografata è generata dalla decrittografia della chiave e del vettore di inizializzazione
- Eliminato l’esagono che cambia invece di org.apache.commons codec routine esagonali
Alcune note: utilizzare una crittografia di 128 bit chiave Java, apparentemente, non 256 fuori -Le bit di crittografia della scatola. L’applicazione di 256 richiede l’installazione di alcuni file aggiuntivi nella directory di installazione Java.
Inoltre, non sono una persona cripta. Guarda bene.
import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.IOException;import java.io.UnsupportedEncodingException;import java.security.AlgorithmParameters;import java.security.InvalidAlgorithmParameterException;import java.security.InvalidKeyException;import java.security.NoSuchAlgorithmException;import java.security.SecureRandom;import java.security.spec.InvalidKeySpecException;import java.security.spec.InvalidParameterSpecException;import java.security.spec.KeySpec;import javax.crypto.BadPaddingException;import javax.crypto.Cipher;import javax.crypto.CipherInputStream;import javax.crypto.CipherOutputStream;import javax.crypto.IllegalBlockSizeException;import javax.crypto.NoSuchPaddingException;import javax.crypto.SecretKey;import javax.crypto.SecretKeyFactory;import javax.crypto.spec.IvParameterSpec;import javax.crypto.spec.PBEKeySpec;import javax.crypto.spec.SecretKeySpec;import org.apache.commons.codec.DecoderException;import org.apache.commons.codec.binary.Hex;public class Crypto{ String mPassword = null; public final static int SALT_LEN = 8; byte mInitVec = null; byte mSalt = null; Cipher mEcipher = null; Cipher mDecipher = null; private final int KEYLEN_BITS = 128; // see notes below where this is used. private final int ITERATIONS = 65536; private final int MAX_FILE_BUF = 1024; /** * create an object with just the passphrase from the user. Don't do anything else yet * @param password */ public Crypto (String password) { mPassword = password; } /** * return the generated salt for this object * @return */ public byte getSalt () { return (mSalt); } /** * return the initialization vector created from setupEncryption * @return */ public byte getInitVec () { return (mInitVec); } /** * debug/print messages * @param msg */ private void Db (String msg) { System.out.println ("** Crypt ** " + msg); } /** * this must be called after creating the initial Crypto object. It creates a salt of SALT_LEN bytes * and generates the salt bytes using secureRandom(). The encryption secret key is created * along with the initialization vectory. The member variable mEcipher is created to be used * by the class later on when either creating a CipherOutputStream, or encrypting a buffer * to be written to disk. * * @throws NoSuchAlgorithmException * @throws InvalidKeySpecException * @throws NoSuchPaddingException * @throws InvalidParameterSpecException * @throws IllegalBlockSizeException * @throws BadPaddingException * @throws UnsupportedEncodingException * @throws InvalidKeyException */ public void setupEncrypt () throws NoSuchAlgorithmException, InvalidKeySpecException, NoSuchPaddingException, InvalidParameterSpecException, IllegalBlockSizeException, BadPaddingException, UnsupportedEncodingException, InvalidKeyException { SecretKeyFactory factory = null; SecretKey tmp = null; // crate secureRandom salt and store as member var for later use mSalt = new byte ; SecureRandom rnd = new SecureRandom (); rnd.nextBytes (mSalt); Db ("generated salt :" + Hex.encodeHexString (mSalt)); factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1"); /* Derive the key, given password and salt. * * in order to do 256 bit crypto, you have to muck with the files for Java's "unlimted security" * The end user must also install them (not compiled in) so beware. * see here: http://www.javamex.com/tutorials/cryptography/unrestricted_policy_files.shtml */ KeySpec spec = new PBEKeySpec (mPassword.toCharArray (), mSalt, ITERATIONS, KEYLEN_BITS); tmp = factory.generateSecret (spec); SecretKey secret = new SecretKeySpec (tmp.getEncoded(), "AES"); /* Create the Encryption cipher object and store as a member variable */ mEcipher = Cipher.getInstance ("AES/CBC/PKCS5Padding"); mEcipher.init (Cipher.ENCRYPT_MODE, secret); AlgorithmParameters params = mEcipher.getParameters (); // get the initialization vectory and store as member var mInitVec = params.getParameterSpec (IvParameterSpec.class).getIV(); Db ("mInitVec is :" + Hex.encodeHexString (mInitVec)); } /** * If a file is being decrypted, we need to know the pasword, the salt and the initialization vector (iv). * We have the password from initializing the class. pass the iv and salt here which is * obtained when encrypting the file initially. * * @param initvec * @param salt * @throws NoSuchAlgorithmException * @throws InvalidKeySpecException * @throws NoSuchPaddingException * @throws InvalidKeyException * @throws InvalidAlgorithmParameterException * @throws DecoderException */ public void setupDecrypt (String initvec, String salt) throws NoSuchAlgorithmException, InvalidKeySpecException, NoSuchPaddingException, InvalidKeyException, InvalidAlgorithmParameterException, DecoderException { SecretKeyFactory factory = null; SecretKey tmp = null; SecretKey secret = null; // since we pass it as a string of input, convert to a actual byte buffer here mSalt = Hex.decodeHex (salt.toCharArray ()); Db ("got salt " + Hex.encodeHexString (mSalt)); // get initialization vector from passed string mInitVec = Hex.decodeHex (initvec.toCharArray ()); Db ("got initvector :" + Hex.encodeHexString (mInitVec)); /* Derive the key, given password and salt. */ // in order to do 256 bit crypto, you have to muck with the files for Java's "unlimted security" // The end user must also install them (not compiled in) so beware. // see here: // http://www.javamex.com/tutorials/cryptography/unrestricted_policy_files.shtml factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1"); KeySpec spec = new PBEKeySpec(mPassword.toCharArray (), mSalt, ITERATIONS, KEYLEN_BITS); tmp = factory.generateSecret(spec); secret = new SecretKeySpec(tmp.getEncoded(), "AES"); /* Decrypt the message, given derived key and initialization vector. */ mDecipher = Cipher.getInstance("AES/CBC/PKCS5Padding"); mDecipher.init(Cipher.DECRYPT_MODE, secret, new IvParameterSpec(mInitVec)); } /** * This is where we write out the actual encrypted data to disk using the Cipher created in setupEncrypt(). * Pass two file objects representing the actual input (cleartext) and output file to be encrypted. * * there may be a way to write a cleartext header to the encrypted file containing the salt, but I ran * into uncertain problems with that. * * @param input - the cleartext file to be encrypted * @param output - the encrypted data file * @throws IOException * @throws IllegalBlockSizeException * @throws BadPaddingException */ public void WriteEncryptedFile (File input, File output) throws IOException, IllegalBlockSizeException, BadPaddingException { FileInputStream fin; FileOutputStream fout; long totalread = 0; int nread = 0; byte inbuf = new byte ; fout = new FileOutputStream (output); fin = new FileInputStream (input); while ((nread = fin.read (inbuf)) > 0 ) { Db ("read " + nread + " bytes"); totalread += nread; // create a buffer to write with the exact number of bytes read. Otherwise a short read fills inbuf with 0x0 // and results in full blocks of MAX_FILE_BUF being written. byte trimbuf = new byte ; for (int i = 0; i < nread; i++) trimbuf = inbuf; // encrypt the buffer using the cipher obtained previosly byte tmp = mEcipher.update (trimbuf); // I don't think this should happen, but just in case.. if (tmp != null) fout.write (tmp); } // finalize the encryption since we've done it in blocks of MAX_FILE_BUF byte finalbuf = mEcipher.doFinal (); if (finalbuf != null) fout.write (finalbuf); fout.flush(); fin.close(); fout.close(); fout.close (); Db ("wrote " + totalread + " encrypted bytes"); } /** * Read from the encrypted file (input) and turn the cipher back into cleartext. Write the cleartext buffer back out * to disk as (output) File. * * I left CipherInputStream in here as a test to see if I could mix it with the update() and final() methods of encrypting * and still have a correctly decrypted file in the end. Seems to work so left it in. * * @param input - File object representing encrypted data on disk * @param output - File object of cleartext data to write out after decrypting * @throws IllegalBlockSizeException * @throws BadPaddingException * @throws IOException */ public void ReadEncryptedFile (File input, File output) throws IllegalBlockSizeException, BadPaddingException, IOException { FileInputStream fin; FileOutputStream fout; CipherInputStream cin; long totalread = 0; int nread = 0; byte inbuf = new byte ; fout = new FileOutputStream (output); fin = new FileInputStream (input); // creating a decoding stream from the FileInputStream above using the cipher created from setupDecrypt() cin = new CipherInputStream (fin, mDecipher); while ((nread = cin.read (inbuf)) > 0 ) { Db ("read " + nread + " bytes"); totalread += nread; // create a buffer to write with the exact number of bytes read. Otherwise a short read fills inbuf with 0x0 byte trimbuf = new byte ; for (int i = 0; i < nread; i++) trimbuf = inbuf; // write out the size-adjusted buffer fout.write (trimbuf); } fout.flush(); cin.close(); fin.close (); fout.close(); Db ("wrote " + totalread + " encrypted bytes"); } /** * adding main() for usage demonstration. With member vars, some of the locals would not be needed */ public static void main(String args) { // create the input.txt file in the current directory before continuing File input = new File ("input.txt"); File eoutput = new File ("encrypted.aes"); File doutput = new File ("decrypted.txt"); String iv = null; String salt = null; Crypto en = new Crypto ("mypassword"); /* * setup encryption cipher using password. print out iv and salt */ try { en.setupEncrypt (); iv = Hex.encodeHexString (en.getInitVec ()).toUpperCase (); salt = Hex.encodeHexString (en.getSalt ()).toUpperCase (); } catch (InvalidKeyException e) { e.printStackTrace(); } catch (NoSuchAlgorithmException e) { e.printStackTrace(); } catch (InvalidKeySpecException e) { e.printStackTrace(); } catch (NoSuchPaddingException e) { e.printStackTrace(); } catch (InvalidParameterSpecException e) { e.printStackTrace(); } catch (IllegalBlockSizeException e) { e.printStackTrace(); } catch (BadPaddingException e) { e.printStackTrace(); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } /* * write out encrypted file */ try { en.WriteEncryptedFile (input, eoutput); System.out.printf ("File encrypted to " + eoutput.getName () + "\niv:" + iv + "\nsalt:" + salt + "\n\n"); } catch (IllegalBlockSizeException e) { e.printStackTrace(); } catch (BadPaddingException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } /* * decrypt file */ Crypto dc = new Crypto ("mypassword"); try { dc.setupDecrypt (iv, salt); } catch (InvalidKeyException e) { e.printStackTrace(); } catch (NoSuchAlgorithmException e) { e.printStackTrace(); } catch (InvalidKeySpecException e) { e.printStackTrace(); } catch (NoSuchPaddingException e) { e.printStackTrace(); } catch (InvalidAlgorithmParameterException e) { e.printStackTrace(); } catch (DecoderException e) { e.printStackTrace(); } /* * write out decrypted file */ try { dc.ReadEncryptedFile (eoutput, doutput); System.out.println ("decryption finished to " + doutput.getName ()); } catch (IllegalBlockSizeException e) { e.printStackTrace(); } catch (BadPaddingException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } }}