我想在一个高并发应用程序中使用以下代码,其中某些数据必须加密和解密。所以我需要知道这段代码的哪个部分,如果有的话,应该被同步,以避免不可预测的问题。
public class DesEncrypter {
Cipher ecipher;
Cipher dcipher;
// 8-byte Salt
byte[] salt = {
(byte)0xA9, (byte)0x9B, (byte)0xC8, (byte)0x32,
(byte)0x56, (byte)0x35, (byte)0xE3, (byte)0x03
};
int iterationCount = 19;
DesEncrypter(String passPhrase) {
try {
// Create the key
KeySpec keySpec = new PBEKeySpec(passPhrase.toCharArray(), salt, iterationCount);
SecretKey key = SecretKeyFactory.getInstance( "PBEWithMD5AndDES").generateSecret(keySpec);
ecipher = Cipher.getInstance(key.getAlgorithm());
dcipher = Cipher.getInstance(key.getAlgorithm());
// Prepare the parameter to the ciphers
AlgorithmParameterSpec paramSpec = new PBEParameterSpec(salt, iterationCount);
// Create the ciphers
ecipher.init(Cipher.ENCRYPT_MODE, key, paramSpec);
dcipher.init(Cipher.DECRYPT_MODE, key, paramSpec);
} catch (...)
}
public String encrypt(String str) {
try {
// Encode the string into bytes using utf-8
byte[] utf8 = str.getBytes("UTF8");
// Encrypt
byte[] enc = ecipher.doFinal(utf8);
// Encode bytes to base64 to get a string
return new sun.misc.BASE64Encoder().encode(enc);
} catch (...)
}
public String decrypt(String str) {
try {
// Decode base64 to get bytes
byte[] dec = new sun.misc.BASE64Decoder().decodeBuffer(str);
// Decrypt
byte[] utf8 = dcipher.doFinal(dec);
// Decode using utf-8
return new String(utf8, "UTF8");
} catch (...)
}
}
如果我在每次调用encrypt()和decrypt()方法时都创建一个新的加密器,那么我可以避免并发问题,只是我不确定每次获取一个新的加密器实例会不会有很大的开销。
public String encrypt(String str) {
try {
// Encode the string into bytes using utf-8
byte[] utf8 = str.getBytes("UTF8");
// Encrypt
//new cipher instance
ecipher = Cipher.getInstance(key.getAlgorithm());
byte[] enc = ecipher.doFinal(utf8);
// Encode bytes to base64 to get a string
return new sun.misc.BASE64Encoder().encode(enc);
} catch (...)