import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.InputStream; import java.io.OutputStream; import java.security.Key; import java.security.SecureRandom; import javax.crypto.Cipher; import javax.crypto.CipherInputStream; import javax.crypto.CipherOutputStream; import javax.crypto.KeyGenerator; //java给文件加密使用的md5的加密算法,实例如下: public class FileEncryptionUtil { Key key; public FileEncryptionUtil(String str) { getKey(str);// 生成密匙 System.out.println(key); } /** * 根据参数生成KEY */ public void getKey(String strKey) { try { KeyGenerator _generator = KeyGenerator.getInstance("DES"); _generator.init(new SecureRandom(strKey.getBytes())); this.key = _generator.generateKey(); _generator = null; } catch (Exception e) { throw new RuntimeException("Error initializing SqlMap class. Cause: " + e); } } /** * 文件file进行加密并保存目标文件destFile中 * * @param file * 要加密的文件 如c:/test/srcFile.txt * @param destFile * 加密后存放的文件名 如c:/加密后文件.txt */ public void encrypt(String file, String destFile) throws Exception { long times = System.currentTimeMillis(); // Cipher c = Cipher.getInstance("DES/CBC/PKCS5Padding"); // 参数String transformation的格式是“算法/工作模式/填充模式”,不同的算法支持不同的工作模式以及填充模式。 Cipher cipher = Cipher.getInstance("DES");// 实例化Cipher对象 cipher.init(Cipher.ENCRYPT_MODE, this.key);// 用于将Cipher初始化为加密模式的常量 // 初始化Cipher对象,用于包装 InputStream is = new FileInputStream(file); int size = is.available() / 1024 / 1024; System.out.println("文件大小:" + size + "MB"); OutputStream out = new FileOutputStream(destFile); CipherInputStream cis = new CipherInputStream(is, cipher); byte[] buffer = new byte[1024]; int r; while ((r = cis.read(buffer)) > 0) { out.write(buffer, 0, r); } long allTimes = (System.currentTimeMillis() - times) / 1000; long speed = size / allTimes; System.out.println("完成加密!"); System.out.println("总共耗时:" + allTimes + "秒"); System.out.println("转换速率:" + speed + "MB/秒"); cis.close(); is.close(); out.close(); } /** * 文件采用DES算法解密文件 * * @param file * 已加密的文件 如c:/加密后文件.txt * @param destFile 解密后存放的文件名 如c:/ * test/解密后文件.txt */ public void decrypt(String file, String dest) throws Exception { long times = System.currentTimeMillis(); Cipher cipher = Cipher.getInstance("DES"); cipher.init(Cipher.DECRYPT_MODE, this.key);// 用于将Cipher初始化为解密模式的常量 InputStream is = new FileInputStream(file); int size = is.available() / 1024 / 1024; System.out.println("文件大小:" + size + "MB"); OutputStream out = new FileOutputStream(dest); CipherOutputStream cos = new CipherOutputStream(out, cipher); byte[] buffer = new byte[1024]; int r; while ((r = is.read(buffer)) >= 0) { cos.write(buffer, 0, r); } long allTimes = (System.currentTimeMillis() - times) / 1000; long speed = size / allTimes; System.out.println("完成解密!"); System.out.println("总共耗时:" + allTimes + "秒"); System.out.println("转换速率:" + speed + "MB/秒"); cos.close(); out.close(); is.close(); } public static void main(String[] args) throws Exception { FileEncryptionUtil td = new FileEncryptionUtil("****************"); // td.encrypt("f:/1.avi", "f:/1解密.avi"); // 加密 td.decrypt("f:/1解密.avi", "f:/11.avi"); // 解密 } }
Java Des算法实现高速文件加密解密
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转载自namezhou.iteye.com/blog/2302406
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