对文件加密解密

对文件加密解密 import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.security.Key; import java.security.SecureRandom; import javax.crypto.Cipher; import javax.crypto.KeyGenerator; import javax.crypto.SecretKey; import javax.crypto.spec.SecretKeySpec; /** * Ê?ÓÃAES?ÔÎÄ?þ?øÐÐ?ÓÃܺÍ?âÃÜ * */ public class CipherUtil { /** * Ê?ÓÃAES?ÔÎÄ?þ?øÐÐ?ÓÃܺÍ?âÃÜ * */ private static String type = "AES"; /** * ?ÑÎÄ?þsrcFile?ÓÃܺó?æ??ΪdestFile * @param srcFile ?ÓÃÜÇ?µÄÎÄ?þ * @param destFile ?ÓÃܺóµÄÎÄ?þ * @param privateKey ÃÜÔ? * @throws GeneralSecurityException * @throws IOException */ public void encrypt(String srcFile, String destFile, String privateKey) throws GeneralSecurityException, IOException { Key key = getKey(privateKey); Cipher cipher = Cipher.getInstance(type + "/ECB/PKCS5Padding"); cipher.init(Cipher.ENCRYPT_MODE, key); FileInputStream fis = null; FileOutputStream fos = null; try { fis = new FileInputStream(srcFile); fos = new FileOutputStream(mkdirFiles(destFile)); crypt(fis, fos, cipher); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } finally { if (fis != null) { fis.close(); } if (fos != null) { fos.close(); } } } /** * ?ÑÎÄ?þsrcFile?âÃܺó?æ??ΪdestFile * @param srcFile ?âÃÜÇ?µÄÎÄ?þ * @param destFile ?âÃܺóµÄÎÄ?þ * @param privateKey ÃÜÔ? * @throws GeneralSecurityException * @throws IOException */ public void decrypt(String srcFile, String destFile, String privateKey) throws GeneralSecurityException, IOException { Key key = getKey(privateKey); Cipher cipher = Cipher.getInstance(type + "/ECB/PKCS5Padding"); cipher.init(Cipher.DECRYPT_MODE, key); FileInputStream fis = null; FileOutputStream fos = null; try { fis = new FileInputStream(srcFile); fos = new FileOutputStream(mkdirFiles(destFile)); crypt(fis, fos, cipher); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } finally { if (fis != null) { fis.close(); } if (fos != null) { fos.close(); } } } /** * ?ù?ÝfilePath????ÏàÓ?µÄÄ?Â? * @param filePath Òª????µÄÎÄ?þÂ??- * @return file ÎÄ?þ * @throws IOException */ private File mkdirFiles(String filePath) throws IOException { File file = new File(filePath); if (!file.getParentFile().exists()) { file.getParentFile().mkdirs(); } file.createNewFile(); return file; } /** * Éú?ÉÖ???×Ö?û??µÄÃÜÔ? * @param secret ÒªÉú?ÉÃÜÔ?µÄ×Ö?û?? * @return secretKey Éú?ɺóµÄÃÜÔ? * @throws GeneralSecurityException */ private static Key getKey(String secret) throws GeneralSecurityException { KeyGenerator kgen = KeyGenerator.getInstance(type); kgen.init(128, new SecureRandom(secret.getBytes())); SecretKey secretKey = kgen.generateKey(); return secretKey; } /** * ?ÓÃÜ?âÃÜÁ? * @param in ?ÓÃÜ?âÃÜÇ?µÄÁ? * @param out ?ÓÃÜ?âÃܺóµÄÁ? * @param cipher ?ÓÃÜ?âÃÜ * @throws IOException * @throws GeneralSecurityException */ private static void crypt(InputStream in, OutputStream out, Cipher cipher) throws IOException, GeneralSecurityException { int blockSize = cipher.getBlockSize() * 1000; int outputSize = cipher.getOutputSize(blockSize); byte[] inBytes = new byte[blockSize]; byte[] outBytes = new byte[outputSize]; int inLength = 0; boolean more = true; while (more) { inLength = in.read(inBytes); if (inLength == blockSize) { int outLength = cipher.update(inBytes, 0, blockSize, outBytes); out.write(outBytes, 0, outLength); } else { more = false; } } if (inLength > 0) outBytes = cipher.doFinal(inBytes, 0, inLength); else outBytes = cipher.doFinal(); out.write(outBytes); } }