Crypter et decrypter un fichier avec AES

Bonjour,

J'ai récupéré la classe AESEncryptor de ce forum (http://www.developpez.net/forums/sho...t=13730&page=2)

Code:

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import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.io.OutputStream; import java.security.GeneralSecurityException; import java.security.InvalidKeyException; import java.security.Key; import java.security.NoSuchAlgorithmException; import java.security.SecureRandom; import javax.crypto.Cipher; import javax.crypto.KeyGenerator; import javax.crypto.SecretKey;   /**  *  * @author Absil Romain  */ public class AESEncryptor { /**      * Generates a secret key for AES encrypting and write it in a file.      * @param outputFileNamethe file to write the generated key in.      **/ public static void generateKey(String outputFileName) { try { KeyGenerator keygen = KeyGenerator.getInstance("AES"); SecureRandom random = new SecureRandom(); keygen.init(random); SecretKey key = keygen.generateKey(); ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream(outputFileName)); out.writeObject(key); out.close(); } catch(Exception e) { e.printStackTrace(); } }   /**      * Encryts or decryts (depends on mode) the file inputFileName, and save      * the result in the file outputFileName.      * @param inputFileName the file to encryt or decrypt.      * @param outputFileName the file to save the result of encryting or      * decrypting.      * @param ode the mode : encryption (Cipher.ENCRYPT_MODE) or decryption      * (Cipher.DECRYPT_MODE).      * @see javax.crypto.Cipher      **/ public static void encryptFile(String inputFileName, String outputFileName, String keyFileName, int mode) { InputStream in = null; OutputStream out = null; try { ObjectInputStream keyIn = new ObjectInputStream( new FileInputStream(keyFileName)); Key key = (Key)keyIn.readObject(); keyIn.close();   in = new FileInputStream(inputFileName); out = new FileOutputStream(outputFileName); Cipher cipher = Cipher.getInstance("AES"); cipher.init(mode, key);   crypt(in, out, cipher); in.close(); out.close(); } catch(Exception e) { e.printStackTrace(); } }   private static void crypt(InputStream in, OutputStream out, Cipher cipher) throws IOException, GeneralSecurityException { int blockSize = cipher.getBlockSize(); int outputSize = cipher.getOutputSize(blockSize); byte[] inBytes = new byte[blockSize]; byte[] outBytes = new byte[outputSize];   int inLength = 0; boolean done = false; while(!done) { inLength = in.read(inBytes); if(inLength == blockSize) { int outLength = cipher.update(inBytes, 0, blockSize, outBytes); out.write(outBytes, 0, outLength); } else done = true; }   if(inLength > 0) outBytes = cipher.doFinal(inBytes, 0, inLength); else outBytes = cipher.doFinal();   out.write(outBytes); } public static void main(String[] args){ AESEncryptor.generateKey("key/k.r2o"); //AESEncryptor.encryptFile("test/ch10-crypto.pdf","test/newFileAES","key/k.r2o", Cipher.ENCRYPT_MODE); AESEncryptor.encryptFile("test/newFileAES", "test/ch10-cryptoN.pdf","key/k.r2o", Cipher.DECRYPT_MODE); } }

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J'arrive à crypter mon fichier (enfin je suppose, puisque je ne peux pas le vérifier) avec :

Code:

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AESEncryptor.encryptFile("test/ch10-crypto.pdf","test/newFileAES","key/k.r2o", Cipher.ENCRYPT_MODE);

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mais en voulant décrypter avec :

Code:

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AESEncryptor.encryptFile("test/newFileAES", "test/ch10-cryptoN.pdf","key/k.r2o", Cipher.DECRYPT_MODE);

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j'ai l'exception suivante :

Citation:

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javax.crypto.BadPaddingException: Given final block not properly padded
at com.sun.crypto.provider.SunJCE_h.b(DashoA6275)
at com.sun.crypto.provider.SunJCE_h.b(DashoA6275)
at com.sun.crypto.provider.AESCipher.engineDoFinal(DashoA6275)
at javax.crypto.Cipher.doFinal(DashoA12275)
at AESEncryptor.crypt(AESEncryptor.java:107)
at AESEncryptor.encryptFile(AESEncryptor.java:72)
at AESEncryptor.main(AESEncryptor.java:114)

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J'utilise le jdk1.5.0_03.

Merci de votre aide.

Cette classe est une vielle version que j'ai écrite, en voici une plus récente :

Code:

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package org.cosmopol.crypto;   import java.io.EOFException; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.io.OutputStream; import java.security.InvalidKeyException; import java.security.NoSuchAlgorithmException; import java.security.NoSuchProviderException; import java.security.Provider; import java.security.SecureRandom; import javax.crypto.Cipher; import javax.crypto.KeyGenerator; import javax.crypto.SecretKey; import javax.crypto.NoSuchPaddingException; import javax.crypto.ShortBufferException; import javax.crypto.IllegalBlockSizeException; import javax.crypto.BadPaddingException;   /**  * This class provides methods to generate keys, crypt or decrypt stream and  * files with a symetric-key algorithm such as the AES, DES and so on.  * @author Absil Romain  */ public class SymetricEncryptor extends CipherEncryptor { private SecretKey key; private String algorithm;   /**      * The constant for the AES symetric-key algorithm.      **/ public static String AES = "AES";   /**      * The constant for the DES symetric-key algorithm.      **/ public static String DES = "DES";   /**      * The constant for the triple DES (DES-EDE) symetric-key algorithm.      **/ public static String DES_EDE = "DESede";   /**      * The constant for the Blowfish symetric-key algorithm.      **/ public static String BLOWFISH = "Blowfish";   /**      * The constant for the RC2 symetric-key algorithm.      **/ public static String RC2 = "RC2";   /**      * The constant for the Arcfour symetric-key algorithm.      **/ public static String ARCFOUR = "RC4";   /**      * Constructs a new symetric encryptor with the specified key.<br>      * @param key the secret key to crypt or decrypt datas.      **/ public SymetricEncryptor(SecretKey key) { this.key = key; this.algorithm = key.getAlgorithm(); }   /**      * Constructs a new symetric encryptor with the specified key file name      * containing the secret key.      * @param keyFileName the name of the file containing the secret key.      * @throws java.io.FileNotFoundException if the file containing the secret      * key doesn't exist.      * @throws java.io.IOException if an I/O error occurs during reading the      * key.      * @throws java.lang.ClassNotFoundException if the class of the key is      * unknown.      **/ public SymetricEncryptor(String keyFileName) throws FileNotFoundException, IOException, ClassNotFoundException { ObjectInputStream in = new ObjectInputStream(new FileInputStream(keyFileName)); this.key = (SecretKey)in.readObject(); this.algorithm = key.getAlgorithm(); in.close(); }   /**      * Constructs a new symetric encryptor with the specified key file      * containing the secret key.      * @param keyFile the file containing the secret key.      * @throws java.io.FileNotFoundException if the file containing the secret      * key doesn't exist.      * @throws java.io.IOException if an I/O error occurs during reading the      * key.      * @throws java.lang.ClassNotFoundException if the class of the key is      * unknown.      */ public SymetricEncryptor(File keyFile) throws FileNotFoundException, IOException, ClassNotFoundException { ObjectInputStream in = new ObjectInputStream(new FileInputStream(keyFile)); this.key = (SecretKey)in.readObject(); this.algorithm = key.getAlgorithm(); in.close(); }   /**      * Returns the secret key of the underlying symetric encryptor.      * @return the secret key of the underlying symetric encryptor.      **/ public SecretKey getSecretKey() { return this.key; }   /**      * Returns the algorithm's name of the underlying symetric encryptor.      * @return the algorithm's name of the underlying symetric encryptor.      **/ public String getAlgorithm() { return this.algorithm; }   /**      * Returns a new instance of SymetricEncryptor generated with the specified      * algorithm.      * @param algorithm the algorithm of the symetric encryptor you want to be      * returned.      * @return a new instance of SymetricEncryptor generated with the specified      * algorithm.      * @see org.umh.crypto.SymetricEncryptor#AES      * @see org.umh.crypto.SymetricEncryptor#DES      * @see org.umh.crypto.SymetricEncryptor#DES_EDE      * @see org.umh.crypto.SymetricEncryptor#BLOWFISH      * @see org.umh.crypto.SymetricEncryptor#RC2      * @see org.umh.crypto.SymetricEncryptor#ARCFOUR      * @throws java.security.NoSuchAlgorithmException if the given algorithm      * is invalid.      */ public static SymetricEncryptor getInstance(String algorithm) throws NoSuchAlgorithmException { return new SymetricEncryptor(generateKey(algorithm)); }   /**      * Returns a new instance of SymetricEncryptor generated with the specified      * algorithm and provider name.      * @param algorithm the algorithm of the symetric encryptor you want to be      * returned.      * @param provider the provider's name of the algorithm of the symetric      * encryptor you want to be returned.      * @return a new instance of SymetricEncryptor generated with the specified      * algorithm.      * @see org.umh.crypto.SymetricEncryptor#AES      * @see org.umh.crypto.SymetricEncryptor#DES      * @see org.umh.crypto.SymetricEncryptor#DES_EDE      * @see org.umh.crypto.SymetricEncryptor#BLOWFISH      * @see org.umh.crypto.SymetricEncryptor#RC2      * @see org.umh.crypto.SymetricEncryptor#ARCFOUR      * @throws java.security.NoSuchAlgorithmException if the given algorithm      * is invalid.      * @throws java.security.NoSuchProviderException if the given provider      * is invalid.      */ public static SymetricEncryptor getInstance(String algorithm, String provider) throws NoSuchAlgorithmException, NoSuchProviderException { return new SymetricEncryptor(generateKey(algorithm, provider)); }   /**      * Returns a new instance of SymetricEncryptor generated with the specified      * algorithm and provider.      * @param algorithm the algorithm of the symetric encryptor you want to be      * returned.      * @param provider the provider of the algorithm of the symetric      * encryptor you want to be returned.      * @return a new instance of SymetricEncryptor generated with the specified      * algorithm.      * @see org.umh.crypto.SymetricEncryptor#AES      * @see org.umh.crypto.SymetricEncryptor#DES      * @see org.umh.crypto.SymetricEncryptor#DES_EDE      * @see org.umh.crypto.SymetricEncryptor#BLOWFISH      * @see org.umh.crypto.SymetricEncryptor#RC2      * @see org.umh.crypto.SymetricEncryptor#ARCFOUR      * @throws java.security.NoSuchAlgorithmException if the given algorithm      * is invalid.      */ public static SymetricEncryptor getInstance(String algorithm, Provider provider) throws NoSuchAlgorithmException { return new SymetricEncryptor(generateKey(algorithm, provider)); }   /**      * Returns a secret key generated with the specified algorithm.      * @param algorithm the algorithm of the symetric secret key you want to be      * returned.      * @return a secret key generated with the specified algorithm.      * @see org.umh.crypto.SymetricEncryptor#AES      * @see org.umh.crypto.SymetricEncryptor#DES      * @see org.umh.crypto.SymetricEncryptor#DES_EDE      * @see org.umh.crypto.SymetricEncryptor#BLOWFISH      * @see org.umh.crypto.SymetricEncryptor#RC2      * @see org.umh.crypto.SymetricEncryptor#ARCFOUR      * @throws java.security.NoSuchAlgorithmException if the given algorithm      * is invalid.      */ public static SecretKey generateKey(String algorithm) throws NoSuchAlgorithmException { KeyGenerator keygen = KeyGenerator.getInstance(algorithm); SecureRandom random = new SecureRandom(); keygen.init(random); SecretKey key = keygen.generateKey(); return key; }   /**      * Returns a secret key generated with the specified algorithm and provider      * name.      * @param algorithm the algorithm of the symetric secret key you want to be      * returned.      * @param provider the provider's name of the algorithm of the symetric      * secret key you want to be returned.      * @return a secret key generated with the specified algorithm and provider      * name.      * @see org.umh.crypto.SymetricEncryptor#AES      * @see org.umh.crypto.SymetricEncryptor#DES      * @see org.umh.crypto.SymetricEncryptor#DES_EDE      * @see org.umh.crypto.SymetricEncryptor#BLOWFISH      * @see org.umh.crypto.SymetricEncryptor#RC2      * @see org.umh.crypto.SymetricEncryptor#ARCFOUR      * @throws java.security.NoSuchAlgorithmException if the given algorithm      * is invalid.      * @throws java.security.NoSuchProviderException if the given provider      * is invalid.      */ public static SecretKey generateKey(String algorithm, String provider) throws NoSuchAlgorithmException, NoSuchProviderException { KeyGenerator keygen = KeyGenerator.getInstance(algorithm, provider); SecureRandom random = new SecureRandom(); keygen.init(random); SecretKey key = keygen.generateKey(); return key; }   /**      * Returns a secret key generated with the specified algorithm and provider.      * @param algorithm the algorithm of the symetric secret key you want to be      * returned.      * @param provider the provider of the algorithm of the symetric      * secret key you want to be returned.      * @return a secret key generated with the specified algorithm and provider.      * @see org.umh.crypto.SymetricEncryptor#AES      * @see org.umh.crypto.SymetricEncryptor#DES      * @see org.umh.crypto.SymetricEncryptor#DES_EDE      * @see org.umh.crypto.SymetricEncryptor#BLOWFISH      * @see org.umh.crypto.SymetricEncryptor#RC2      * @see org.umh.crypto.SymetricEncryptor#ARCFOUR      * @throws java.security.NoSuchAlgorithmException if the given algorithm      * is invalid.      */ public static SecretKey generateKey(String algorithm, Provider provider) throws NoSuchAlgorithmException { KeyGenerator keygen = KeyGenerator.getInstance(algorithm, provider); SecureRandom random = new SecureRandom(); keygen.init(random); SecretKey key = keygen.generateKey(); return key; }   /**      * Writes a secret key generated with the specified algorithm to the      * specified output file.      * @param algorithm the algorithm of the symetric secret key you want to be      * written.      * @param outputFileName the name of the file you want the key to be      * written.      * @see org.umh.crypto.SymetricEncryptor#AES      * @see org.umh.crypto.SymetricEncryptor#DES      * @see org.umh.crypto.SymetricEncryptor#DES_EDE      * @see org.umh.crypto.SymetricEncryptor#BLOWFISH      * @see org.umh.crypto.SymetricEncryptor#RC2      * @see org.umh.crypto.SymetricEncryptor#ARCFOUR      * @throws java.security.NoSuchAlgorithmException if the given algorithm      * is invalid.      * @throws java.io.IOException if an I/O error occurs during writing the      * key.      */ public static void generateAndSaveKey(String algorithm, String outputFileName) throws NoSuchAlgorithmException, IOException { SecretKey key = generateKey(algorithm); ObjectOutputStream out = new ObjectOutputStream( new FileOutputStream(outputFileName)); out.writeObject(key); out.close(); }   /**      * Writes a secret key generated with the specified algorithm and provider      * to the specified output file.      * @param algorithm the algorithm of the symetric secret key you want to be      * written.      * @param provider the provider's name of the algorithm.      * @param outputFileName the name of the file you want the key to be      * written.      * @see org.umh.crypto.SymetricEncryptor#AES      * @see org.umh.crypto.SymetricEncryptor#DES      * @see org.umh.crypto.SymetricEncryptor#DES_EDE      * @see org.umh.crypto.SymetricEncryptor#BLOWFISH      * @see org.umh.crypto.SymetricEncryptor#RC2      * @see org.umh.crypto.SymetricEncryptor#ARCFOUR      * @throws java.security.NoSuchAlgorithmException if the given algorithm      * is invalid.      * @throws java.security.NoSuchProviderException if the given provider      * is invalid.      * @throws java.io.IOException if an I/O error occurs during writing the      * key.      */ public static void generateAndSaveKey(String algorithm, String provider, String outputFileName) throws NoSuchAlgorithmException, NoSuchProviderException, IOException { SecretKey key = generateKey(algorithm, provider); ObjectOutputStream out = new ObjectOutputStream( new FileOutputStream(outputFileName)); out.writeObject(key); out.close(); }   /**      * Writes a secret key generated with the specified algorithm and provider      * to the specified output file.      * @param algorithm the algorithm of the symetric secret key you want to be      * written.      * @param provider the provider's name of the algorithm.      * @param outputFileName the name of the file you want the key to be      * written.      * @see org.umh.crypto.SymetricEncryptor#AES      * @see org.umh.crypto.SymetricEncryptor#DES      * @see org.umh.crypto.SymetricEncryptor#DES_EDE      * @see org.umh.crypto.SymetricEncryptor#BLOWFISH      * @see org.umh.crypto.SymetricEncryptor#RC2      * @see org.umh.crypto.SymetricEncryptor#ARCFOUR      * @throws java.security.NoSuchAlgorithmException if the given algorithm      * is invalid.      * @throws java.io.IOException if an I/O error occurs during writing the      * key.      */ public static void generateAndSaveKey(String algorithm, Provider provider, String outputFileName) throws NoSuchAlgorithmException, IOException { SecretKey key = generateKey(algorithm, provider); ObjectOutputStream out = new ObjectOutputStream( new FileOutputStream(outputFileName)); out.writeObject(key); out.close(); }   /**      * Writes a secret key generated with the specified algorithm to the      * specified output file.      * @param algorithm the algorithm of the symetric secret key you want to be      * written.      * @param outputFile the file you want the key to be written.      * @see org.umh.crypto.SymetricEncryptor#AES      * @see org.umh.crypto.SymetricEncryptor#DES      * @see org.umh.crypto.SymetricEncryptor#DES_EDE      * @see org.umh.crypto.SymetricEncryptor#BLOWFISH      * @see org.umh.crypto.SymetricEncryptor#RC2      * @see org.umh.crypto.SymetricEncryptor#ARCFOUR      * @throws java.security.NoSuchAlgorithmException if the given algorithm      * is invalid.      * @throws java.io.IOException if an I/O error occurs during writing the      * key.      */ public static void generateAndSaveKey(String algorithm, File outputFile) throws NoSuchAlgorithmException, IOException { SecretKey key = generateKey(algorithm); ObjectOutputStream out = new ObjectOutputStream( new FileOutputStream(outputFile)); out.writeObject(key); out.close(); }   /**      * Writes a secret key generated with the specified algorithm and provider      * to the specified output file.      * @see org.umh.crypto.SymetricEncryptor#AES      * @see org.umh.crypto.SymetricEncryptor#DES      * @see org.umh.crypto.SymetricEncryptor#DES_EDE      * @see org.umh.crypto.SymetricEncryptor#BLOWFISH      * @see org.umh.crypto.SymetricEncryptor#RC2      * @see org.umh.crypto.SymetricEncryptor#ARCFOUR      * @param algorithm the algorithm of the symetric secret key you want to be      * written.      * @param provider the provider's name of the algorithm.      * @param outputFile the file you want the key to be written.      * @throws java.security.NoSuchProviderException if the given provider is invalid.      * @throws java.security.NoSuchAlgorithmException if the given algorithm is invalid.      * @throws java.io.IOException if an I/O error occurs during writing the      * key.      */ public static void generateAndSaveKey(String algorithm, String provider, File outputFile) throws NoSuchAlgorithmException, NoSuchProviderException, IOException { SecretKey key = generateKey(algorithm, provider); ObjectOutputStream out = new ObjectOutputStream( new FileOutputStream(outputFile)); out.writeObject(key); out.close(); }   /**      * Writes a secret key generated with the specified algorithm and provider      * to the specified output file.      * @param algorithm the algorithm of the symetric secret key you want to be      * written.      * @param provider the provider's name of the algorithm.      * @param outputFile the file you want the key to be written.      * @see org.umh.crypto.SymetricEncryptor#AES      * @see org.umh.crypto.SymetricEncryptor#DES      * @see org.umh.crypto.SymetricEncryptor#DES_EDE      * @see org.umh.crypto.SymetricEncryptor#BLOWFISH      * @see org.umh.crypto.SymetricEncryptor#RC2      * @see org.umh.crypto.SymetricEncryptor#ARCFOUR      * @throws java.security.NoSuchAlgorithmException if the given algorithm      * is invalid.      * @throws java.io.IOException if an I/O error occurs during writing the      * key.      */ public static void generateAndSaveKey(String algorithm, Provider provider, File outputFile) throws NoSuchAlgorithmException, IOException { SecretKey key = generateKey(algorithm, provider); ObjectOutputStream out = new ObjectOutputStream( new FileOutputStream(outputFile)); out.writeObject(key); out.close(); }   /**      * Encrypts the specified input file to the specified output file with the      * underlying symetric encryptor.      * @param inputFileName the name of the file you want to be encrypted.      * @param outputFileName the name of the file where you want the encrypted      * datas to be written.      * @throws FileNotFoundException if the input file doesn't exists.      * @throws IOException if an I/O error occurs during reading the input file      * or writting the encrypted datas to the output file.      * @throws InvalidKeyException if the key of the underlying symetric      * encryptor is not a valid key for this operation.      * @throws NoSuchPaddingException if the algorithm contains a padding      * scheme that is not available.      **/ public void encryptFile(String inputFileName, String outputFileName) throws FileNotFoundException, IOException, InvalidKeyException, NoSuchPaddingException { InputStream in = new FileInputStream(inputFileName); OutputStream out = new FileOutputStream(outputFileName); Cipher cipher = null; try { cipher = Cipher.getInstance(algorithm); } catch(NoSuchAlgorithmException ex)//never launched { ex.printStackTrace(); }   cipher.init(Cipher.ENCRYPT_MODE, key);   super.crypt(in, out, cipher); in.close(); out.close(); }   /**      * Encrypts the specified input file to the specified output file with the      * underlying symetric encryptor.      * @param inputFile the file you want to be encrypted.      * @param outputFile the file  where you want the encrypted datas to be      * written.      * @throws FileNotFoundException if the input file doesn't exists.      * @throws IOException if an I/O error occurs during reading the input file      * or writting the encrypted datas to the output file.      * @throws InvalidKeyException if the key of the underlying symetric      * encryptor is not a valid key for this operation.      * @throws NoSuchPaddingException if the algorithm contains a padding      * scheme that is not available.      **/ public void encryptFile(File inputFile, File outputFile) throws FileNotFoundException, IOException, InvalidKeyException, NoSuchPaddingException { InputStream in = new FileInputStream(inputFile); OutputStream out = new FileOutputStream(outputFile); Cipher cipher = null; try { cipher = Cipher.getInstance(algorithm); } catch(NoSuchAlgorithmException ex)//never launched { ex.printStackTrace(); }   cipher.init(Cipher.ENCRYPT_MODE, key);   super.crypt(in, out, cipher); in.close(); out.close(); }   /**      * Decrypts the specified input file to the specified output file with the      * underlying symetric encryptor.      * @param inputFileName the name of the file you want to be decrypted.      * @param outputFileName the name of the file where you want the decrypted      * datas to be written.      * @throws FileNotFoundException if the input file doesn't exists.      * @throws IOException if an I/O error occurs during reading the input file      * or writting the decrypted datas to the output file.      * @throws InvalidKeyException if the key of the underlying symetric      * encryptor is not a valid key for this operation.      * @throws NoSuchPaddingException if the algorithm contains a padding      * scheme that is not available.      **/ public void decryptFile(String inputFileName, String outputFileName) throws FileNotFoundException, IOException, InvalidKeyException, NoSuchPaddingException { InputStream in = new FileInputStream(inputFileName); OutputStream out = new FileOutputStream(outputFileName); Cipher cipher = null; try { cipher = Cipher.getInstance(algorithm); } catch(NoSuchAlgorithmException ex)//never launched { ex.printStackTrace(); }   cipher.init(Cipher.DECRYPT_MODE, key);   super.crypt(in, out, cipher); in.close(); out.close(); }   /**      * Decrypts the specified input file to the specified output file with the      * underlying symetric encryptor.      * @param inputFile the file you want to be decrypted.      * @param outputFile the file where you want the decrypted datas to be      * written.      * @throws FileNotFoundException if the input file doesn't exists.      * @throws IOException if an I/O error occurs during reading the input file      * or writting the decrypted datas to the output file.      * @throws InvalidKeyException if the key of the underlying symetric      * encryptor is not a valid key for this operation.      * @throws NoSuchPaddingException if the algorithm contains a padding      * scheme that is not available.      **/ public void decryptFile(File inputFile, File outputFile) throws FileNotFoundException, IOException, InvalidKeyException, NoSuchPaddingException { InputStream in = new FileInputStream(inputFile); OutputStream out = new FileOutputStream(outputFile); Cipher cipher = null; try { cipher = Cipher.getInstance(algorithm); } catch(NoSuchAlgorithmException ex)//never launched { ex.printStackTrace(); }   cipher.init(Cipher.DECRYPT_MODE, key);   super.crypt(in, out, cipher); in.close(); out.close(); }   /**      * Encrypts the specified input stream to the specified output stream with      * the underlying symetric encryptor.      * @param in the input stream you want to be encrypted.      * @param out the output stream where you want the encrypted datas to be      * written.      * @throws IOException if an I/O error occurs during reading the input stream      * or writting the decrypted datas to the output stream.      * @throws InvalidKeyException if the key of the underlying symetric      * encryptor is not a valid key for this operation.      * @throws NoSuchPaddingException if the algorithm contains a padding      * scheme that is not available.      **/ public void encryptStream(InputStream in, OutputStream out) throws IOException, InvalidKeyException, NoSuchPaddingException { Cipher cipher = null; try { cipher = Cipher.getInstance(algorithm); } catch(NoSuchAlgorithmException ex)//never launched { ex.printStackTrace(); }   cipher.init(Cipher.ENCRYPT_MODE, key);   super.crypt(in, out, cipher); in.close(); out.close(); }   /**      * Decrypts the specified input stream to the specified output stream with      * the underlying symetric encryptor.      * @param in the input stream you want to be decrypted.      * @param out the output stream where you want the decrypted datas to be      * written.      * @throws IOException if an I/O error occurs during reading the input stream      * or writting the decrypted datas to the output stream.      * @throws InvalidKeyException if the key of the underlying symetric      * encryptor is not a valid key for this operation.      * @throws NoSuchPaddingException if the algorithm contains a padding      * scheme that is not available.      */ public void decryptStream(InputStream in, OutputStream out) throws IOException, InvalidKeyException, NoSuchPaddingException { Cipher cipher = null; try { cipher = Cipher.getInstance(algorithm); } catch(NoSuchAlgorithmException ex)//never launched { ex.printStackTrace(); }   cipher.init(Cipher.DECRYPT_MODE, key);   super.crypt(in, out, cipher); in.close(); out.close(); }   }

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Si tu as des questions n'hésite pas;)
Désolé pour le cotretemps dû à maclasse, il faut vraiment que je nettoie toutes les veilles classes postées et que je les remplace par les mises à jour...

Et voici la superclasse indispensable :

Code:

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package org.cosmopol.crypto;   import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.util.ArrayList; import javax.crypto.BadPaddingException; import javax.crypto.Cipher; import javax.crypto.IllegalBlockSizeException; import javax.crypto.ShortBufferException;   /**  * This class models cipher algorithm encryptors wich are represented by  * their stream and bytes encryption method.  * @author Absil Romain  */ public class CipherEncryptor { /**      * Crypts or decrypts the specified input stream to the specified output      * stream with a given cipher. The crypting or decrypting operation is      * determined by the cipher's state.      * @param cipher The cipher used to crypt the specified input stream to the specified output      * stream.      * @param in the input srteal stream to be encypted or decrypted.      * @param out the output stream to be encypted or decrypted.      * @throws java.io.IOException if an I/O error occurs during crypting the input stream to the output stream.      */ public void crypt(InputStream in, OutputStream out, Cipher cipher) throws IOException { int blockSize = cipher.getBlockSize(); int outputSize = cipher.getOutputSize(blockSize); byte[] inBytes = new byte[blockSize]; byte[] outBytes = new byte[outputSize];   int inLength = 0; boolean done = false; while(!done) { inLength = in.read(inBytes); if(inLength == blockSize) { try { int outLength = cipher.update(inBytes, 0, blockSize, outBytes); out.write(outBytes, 0, outLength); } catch(ShortBufferException e) { e.printStackTrace(); } } else done = true; }   try { if(inLength > 0) outBytes = cipher.doFinal(inBytes, 0, inLength); else outBytes = cipher.doFinal(); out.write(outBytes); } catch(IllegalBlockSizeException e) { e.printStackTrace(); } catch(BadPaddingException e) { e.printStackTrace(); } }   }

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OK merci,
je vais regarder ça de près ce soir et je te tiens au courant.
MarsOran.
au fait, quel algo (AES, DES, BlowFish..etc) me conseilles tu ? c'est pour une application WEB (J2EE) qui stocke des documents (plus ou moins important).

Les puissances des algos sont plus ou moins équivalentes, mais ne prend pas le DES il est considéré à présent comme obsolète, et avec de l'achernement on sait le casser. Non si pas prend l'AES, c'est un standart. Mais bon le stress vient du problème de transmition des clés (voir mes post dans la rubrique contribuez pour plus d'explication). Si tu veux vraiment bien sécuriser prend ma classe qui crypte en RSA (dans la même rubrique).

OK, dans ce cas, c'est bon, le programme RSA fonctionne correctement, merci.

le problème avec ces algos, c'est la clé qu'il faut bien cacher !! car je stocke mon document dans un répertoire (de mon serveur) et la clé (fichier) dans un autre répertoire (avec un nom et une extension un peu dissimulé), le problème, est que si quelqu'un retrouve la clé et sache faire le lien avec le document correspondant (en sachant aussi que c'est RSA) ->il pourra facilement décrypter les docs !! c'est une chance minim que ça arrive mais bon !!
MarsOran.

Tu peux (tu dois) crypter la clé privée avec un algorithme comme PBE (Password Based Encryption). Cet algorithme règle le problème de gestion des clés car il utilise une phrase comme mot de passe. Donc, tu donnes un mot de passe à PBD (assez long bien sûr) et il va te crypter le fichier de ta clé privée. Tu pourras récupérer la clé en décryptant avec le mot de passe.

Tout cela est possible avec Java, car ce dernier gère PBE.

Fait une petite recherche pour savoir comment il faut faire au niveau du code.

Bonne chance.

OK, merci.
Je pense que je vais opté pour ce procédé même si, il faut sauvegarder deux paramètres (le "salt" et "iterations") (je pense que je vais les mettre dans la BD)
MarsOran.

Le problème de cacher la clé ne se pose pas dans le cas d'un algorithme de clé privée comme le RSA, à la génération tu garde sur toi la clé privée et tu ne la stocke pas. La clé publique tu la donne à qui tu veux, en effet celle-ci ne sert qu'à crypter les documents, et ce n'est pas une opération que tu souhate protéger (en effet on crypte en général un document pour que des tiers ne puissent pas le lire, i.e. ils doivent être incapable de le décrypter).

Une fois le jeu de clé généré, tu mets la clé publique dans un endroit accéssible à tout le monde, afin que quiconque voulant te remettre des documents ensibles puisse les crypter, empêchant ainsi toute autre personne que toi (même la personne qui la crypté) de le lire. Toi seul possède donc la capacité de décrypter.

Pour le cryptage avec PBE, je sais pas comment on fait personellement, mais c'est vrai que c'est plus facile de retenir une phrase que deux nombres, même si je considère que même si elle est cryptée, stocker la clé au même endroit que les fichiers représente une faille de sécurité. Plutôt que de demander une authentification avec login, password, et phrase pour décrypter, demande plutôt login, password et fichier contenant la clé privée (à ce moment-là tu insère un périphérique (clé USB,...) contenant la clé et tu lui donnes. Ca marche tout aussi bien, on ne perd pas de temps à crypter / décrypter la clé, et n'importe qui peut aisément comprendre que ce niveau de sécurité est supérieur à un stockage physique sur ton disque de la clé privée, même si elle est cryptée (en effet on a toujours plus de chance de la décrypter si elle est présente sur le disque que si elle ne l'est pas, sans compter que si un quidam furieux de ne pas avoir su lire les fichiers supprime ta clé, tes fichiers sont définivement perdus).

En résumé, si j'étais toi, je n'utiliserai pas PBE pour crypter la clé privée, je la garderai tout le temps sur moi (ou avec les personnes de confiance ayant l'authorisation de consulter les documnts), sur un support amovible. Quand tu lance ton programme, tu demande un login et un pass, afin de fournir quelques services de base, et chaque fois que le programme a besoin de décrypter, tu demande la clé privée.

Voilà donc;)

Je reviens que quelque mots échangé autour du chiffrement de documents, et perso, je déconseille très fortement d'utiliser RSA pour chiffrer des documents car on rencontrera des problèmes de perf lors du déchiffrement, le plus sage serai de chiffrer les documents en AES, puis chiffrer la clé AES en RSA, cela donne nettement des résultats meilleurs allant jusqu'a un rapport de 20 000 entre les deux solutions.

Si vous avez d'autre proposition, je suis preneur :mrgreen: