DES加密/解密操作

生成DES密钥、保存密钥到文件、从文件读取密钥、加密、解密等操作。

java 代码

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.Security;
import java.security.spec.InvalidKeySpecException;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import org.apache.commons.configuration.ConfigurationException;
import org.apache.commons.configuration.PropertiesConfiguration;
import com.sun.crypto.provider.SunJCE;

public class DESTest {
    private static final String ALGORITHM = "DES";

    /**
     * 获得DES加密的密钥。在交易处理的过程中应该定时更 换密钥。需要JCE的支持，如果jdk版本低于1.4，则需要
     * 安装jce-1_2_2才能正常使用。
     *
     * @return Key 返回对称密钥
     * @throws java.security.NoSuchAlgorithmException
     * @see util.EncryptUtil 其中包括加密和解密的方法
     */
    public Key generateKey() throws EncryptException {
        try {
            Security.insertProviderAt(new SunJCE(), 1);
            KeyGenerator generator = KeyGenerator.getInstance(ALGORITHM);
            generator.init(new SecureRandom());
            Key key = generator.generateKey();
            return key;
        } catch (NoSuchAlgorithmException e) {
            throw new EncryptException(e);
        }
    }

    /**
     * 得到一个密钥的密码
     *
     * @param key
     *            密钥
     * @param cipherMode
     *            密码的类型
     * @return Cipher
     * @throws util.EncryptException
     *             当加密出现异常情况时,产生异常信息
     */
    public Cipher getCipher(Key key, int cipherMode) throws EncryptException {
        try {
            Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
            cipher.init(cipherMode, key);
            return cipher;
        } catch (Exception e) {
            // e.printStackTrace();
            throw new EncryptException("Generate Cipher occurs Exception.["
                    + e.getMessage() + "]");
        }
    }

    public void saveKey(Key key, String filename) throws EncryptException {
        if (key == null) {
            return;
        }

        File file = new File(filename);
        try {
            file.createNewFile();
        } catch (IOException e1) {
            throw new EncryptException(e1);
        }

        try {
            PropertiesConfiguration publicConfig = new PropertiesConfiguration(
                    filename);
            publicConfig.setProperty("Key", Utils.bytesToHexStr(key
                    .getEncoded()));
            publicConfig.save();
        } catch (ConfigurationException e) {
            throw new EncryptException(e);
        }
    }

    public Key loadKey(String filename) throws EncryptException {
        try {
            PropertiesConfiguration config = new PropertiesConfiguration(
                    new File(filename));
            String privateKeyValue = config.getString("Key");
            // 从原始密钥数据创建DESKeySpec对象
            DESKeySpec dks = new DESKeySpec(Utils
                    .hexStrToBytes(privateKeyValue));
            // 创建一个密钥工厂，然后用它把DESKeySpec转换成Secret Key对象
            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
            Key key = keyFactory.generateSecret(dks);
            return key;
        } catch (ConfigurationException e) {
            throw new EncryptException(e);
        } catch (NoSuchAlgorithmException e) {
            throw new EncryptException(e);
        } catch (InvalidKeyException e) {
            throw new EncryptException(e);
        } catch (InvalidKeySpecException e) {
            throw new EncryptException(e);
        }
    }

    public byte[] doEncrypt(Key key, byte[] data) throws EncryptException {
        try {
            // Get a cipher object
            Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");

            // Encrypt
            cipher.init(Cipher.ENCRYPT_MODE, key);
            // byte[] stringBytes = amalgam.getBytes("UTF8");
            byte[] raw = cipher.doFinal(data);
            // BASE64Encoder encoder = new BASE64Encoder();
            // String base64 = encoder.encode(raw);
            return raw;
        } catch (Exception e) {
            e.printStackTrace();
            throw new EncryptException("Do encrypt occurs Exception.["
                    + e.getMessage() + "]");
        }
    }

    public byte[] doDecrypt(Key key, byte[] raw) throws EncryptException {
        try {
            // Get a cipher object
            Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
            // Decrypt
            cipher.init(Cipher.DECRYPT_MODE, key);
            // BASE64Decoder decoder = new BASE64Decoder();
            // byte[] raw = decoder.decodeBuffer(data);
            byte[] data = cipher.doFinal(raw);
            // String result = new String(stringBytes, "UTF8");
            // System.out.println("the decrypted data is: " + result);
            return data;
        } catch (Exception e) {
            e.printStackTrace();
            throw new EncryptException("Do decrypt occurs Exception.["
                    + e.getMessage() + "]");
        }
    }

    public static void main(String[] args) {
        DESTest bean = new DESTest();
        String keyFilename = "d:/key.txt";
        String srcFilename = "d:/temp/1.txt";
        String encryptFilename = "D:/temp/encrypt_result.dat";
        String decryptFilename = "D:/temp/decrypt_result.txt";

        Key key = bean.initKey(keyFilename);
        DESEncrypt encrypt = DESEncryptImpl.getInstance();

        try {
            // encrypt
            System.out.println("encrypt begin ...");
            FileInputStream in = new FileInputStream(srcFilename);
            ByteArrayOutputStream bout = new ByteArrayOutputStream();
            byte[] tmpbuf = new byte[1024];
            int count = 0;
            while ((count = in.read(tmpbuf)) != -1) {
                bout.write(tmpbuf, 0, count);
                tmpbuf = new byte[1024];
            }
            in.close();
            byte[] orgData = bout.toByteArray();
            byte[] raw = encrypt.doEncrypt(key, orgData);

            OutputStream out = new FileOutputStream(new File(encryptFilename));
            out.write(raw);
            out.close();
            System.out.println("encrypt done ...");

            // decrypt
            System.out.println("decrypt begin ...");
            in = new FileInputStream(encryptFilename);
            bout = new ByteArrayOutputStream();
            tmpbuf = new byte[1024];
            count = 0;
            while ((count = in.read(tmpbuf)) != -1) {
                bout.write(tmpbuf, 0, count);
                tmpbuf = new byte[1024];
            }
            in.close();
            orgData = bout.toByteArray();
            byte[] data = encrypt.doDecrypt(key, orgData);
            out = new FileOutputStream(new File(decryptFilename));
            out.write(data);
            out.flush();
            out.close();
            System.out.println("decrypt done ...");
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (EncryptException e) {
            e.printStackTrace();
        }
    }

    /*
     * test
     */
    public Key initKey(String keyFilename) {
        DESControl control = DESControlImpl.getInstance();
        File keyFile = new File(keyFilename);
        Key key = null;
        try {
            if (!keyFile.exists()) {
                System.out.println("generate Key.");
                key = control.generateKey();
                control.saveKey(key, keyFilename);
                return key;

            } else {
                System.out.println("load Key.");
                key = control.loadKey(keyFilename);
                return key;
            }
        } catch (EncryptException e) {
            e.printStackTrace();
        }
        return key;
    }
}

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MD5、SHA的加密 | Java 压缩解压缩文件

• 2007-10-23 10:34
• 浏览 3826
• 评论(1)
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评论

1 楼 hywill 2010-04-14  

您好，我最近在做文件压缩加密的功能，请问密钥从哪儿获取呢？
key.txt里面是什么？还望您的指教