使用AES对文件的加解密

使用AES对文件的加解密:

Java代码







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;

/**

* 使用AES对文件进行加密和解密

*

*/

public
class CipherUtil {

/**

* 使用AES对文件进行加密和解密

*
*/

private
static String type =
"AES";

/**

* 把文件srcFile加密后存储为destFile

* @param srcFile 加密前的文件

* @param destFile 加密后的文件

* @param privateKey 密钥

* @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();
}
}
}

/**

* 把文件srcFile解密后存储为destFile

* @param srcFile 解密前的文件

* @param destFile 解密后的文件

* @param privateKey 密钥

* @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();
}
}
}

/**

* 根据filePath创建相应的目录

* @param filePath 要创建的文件路经

* @return file 文件

* @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;

}

/**

* 生成指定字符串的密钥

* @param secret 要生成密钥的字符串

* @return secretKey 生成后的密钥

* @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;

}

/**

* 加密解密流

* @param in 加密解密前的流

* @param out 加密解密后的流

* @param cipher 加密解密

* @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);
}
}