更新时间:2022-09-13 18:52:34
密码学中两种常见的密码算法为:对称密码算法和非对称密码算法。
对称密钥加密,又称私钥加密,即信息的发送方和接收方用一个密钥去加密和解密数据。它的最大优势是加/解密速度快,适合于对大数据量进行加密,但密钥管理困难。
非对称密钥加密,又称公钥密钥加密。它需要使用一对密钥来分别完成加密和解密操作,一个公开发布,即公开密钥,另一个由用户自己秘密保存,即私用密钥。信息发送者用公开密钥去加密,而信息接收者则用私用密钥去解密。公钥机制灵活,但加密和解密速度却比对称密钥加密慢得多。
对称加密算法用来对敏感数据等信息进行加密,常用的算法包括:
DES(Data Encryption Standard):数据加密标准,速度较快,适用于加密大量数据的场合。
3DES(Triple DES):是基于DES,对一块数据用三个不同的密钥进行三次加密,强度更高。
AES(Advanced Encryption Standard):高级加密标准,是下一代的加密算法标准,速度快,安全级别高;
Mysql官网手册
https://dev.mysql.com/doc/refman/5.7/en/encryption-functions.html#function_aes-encrypt
MySQL的内置加密函数里已经不推荐DES算法,所以选用AES算法来加解密账号密码。
AES算法加解密都需要同一个key,如果这个key用来加密所有账号的密码,那么密码相同的不同账号得到的加密结果是相同的,这样会降低安全性,所以用可以唯一标识账号的aid来当做key,为了更不容易反向推导出key,实际应用中会用一个内部的salt字符串拼上账号aid来作为key。
为了灵活和重用,没使用MySQL内置函数,改用Java实现。
AES算法实现与操作系统有关,本实现兼容Windows/Linux。
加密后获得的是byte[]类型结果,因此数据库内相应字段的类型应为BLOB,节省空间用TinyBlob类型就够。
加密算法需要使用外部类库javabase64-1.3.1.jar百度网盘下载链接
Java实现有两个类:
AESUtils:提供加解密静态方法
Base64Utils :辅助AESUtils类
AESUtils常用方法说明:
方法 |
返回 |
说明 |
参数 |
getSecretKey(String seed) |
String |
生成key |
seed: salt+aid |
encrypt(byte[] data, String key) |
byte[] |
加密 |
data: 密码明文getBytes(“UTF-8”) key: getScretKey方法结果 |
decrypt(byte[] data, String key) |
byte[] |
解密 |
data: 密码密文 key: getScretKey方法结果 |
AESUtils.java:
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import java.io.File;
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;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
public class AESUtils {
private static final String ALGORITHM = "AES" ;
private static final int KEY_SIZE = 128 ;
private static final int CACHE_SIZE = 1024 ;
public static String getSecretKey() throws Exception {
return getSecretKey( null );
}
public static String getSecretKey(String seed) throws Exception {
try {
KeyGenerator _generator = KeyGenerator.getInstance(ALGORITHM);
SecureRandom secureRandom = SecureRandom.getInstance( "SHA1PRNG" );
secureRandom.setSeed(seed.getBytes( "UTF-8" ));
_generator.init(KEY_SIZE, secureRandom);
SecretKey secretKey = _generator.generateKey();
return Base64Utils.encode(secretKey.getEncoded());
} catch (Exception e) {
throw new RuntimeException( "初始化密钥出现异常" );
}
}
public static byte [] encrypt( byte [] data, String key) throws Exception {
Key k = toKey(Base64Utils.decode(key));
byte [] raw = k.getEncoded();
SecretKeySpec secretKeySpec = new SecretKeySpec(raw, ALGORITHM);
Cipher cipher = Cipher.getInstance(ALGORITHM);
cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);
return cipher.doFinal(data);
}
public static void encryptFile(String key, String sourceFilePath, String destFilePath) throws Exception {
File sourceFile = new File(sourceFilePath);
File destFile = new File(destFilePath);
if (sourceFile.exists() && sourceFile.isFile()) {
if (!destFile.getParentFile().exists()) {
destFile.getParentFile().mkdirs();
}
destFile.createNewFile();
InputStream in = new FileInputStream(sourceFile);
OutputStream out = new FileOutputStream(destFile);
Key k = toKey(Base64Utils.decode(key));
byte [] raw = k.getEncoded();
SecretKeySpec secretKeySpec = new SecretKeySpec(raw, ALGORITHM);
Cipher cipher = Cipher.getInstance(ALGORITHM);
cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);
CipherInputStream cin = new CipherInputStream(in, cipher);
byte [] cache = new byte [CACHE_SIZE];
int nRead = 0 ;
while ((nRead = cin.read(cache)) != - 1 ) {
out.write(cache, 0 , nRead);
out.flush();
}
out.close();
cin.close();
in.close();
}
}
public static byte [] decrypt( byte [] data, String key) throws Exception {
Key k = toKey(Base64Utils.decode(key));
byte [] raw = k.getEncoded();
SecretKeySpec secretKeySpec = new SecretKeySpec(raw, ALGORITHM);
Cipher cipher = Cipher.getInstance(ALGORITHM);
cipher.init(Cipher.DECRYPT_MODE, secretKeySpec);
return cipher.doFinal(data);
}
public static void decryptFile(String key, String sourceFilePath, String destFilePath) throws Exception {
File sourceFile = new File(sourceFilePath);
File destFile = new File(destFilePath);
if (sourceFile.exists() && sourceFile.isFile()) {
if (!destFile.getParentFile().exists()) {
destFile.getParentFile().mkdirs();
}
destFile.createNewFile();
FileInputStream in = new FileInputStream(sourceFile);
FileOutputStream out = new FileOutputStream(destFile);
Key k = toKey(Base64Utils.decode(key));
byte [] raw = k.getEncoded();
SecretKeySpec secretKeySpec = new SecretKeySpec(raw, ALGORITHM);
Cipher cipher = Cipher.getInstance(ALGORITHM);
cipher.init(Cipher.DECRYPT_MODE, secretKeySpec);
CipherOutputStream cout = new CipherOutputStream(out, cipher);
byte [] cache = new byte [CACHE_SIZE];
int nRead = 0 ;
while ((nRead = in.read(cache)) != - 1 ) {
cout.write(cache, 0 , nRead);
cout.flush();
}
cout.close();
out.close();
in.close();
}
}
private static Key toKey( byte [] key) throws Exception {
SecretKey secretKey = new SecretKeySpec(key, ALGORITHM);
return secretKey;
}
} |
Base64Utils.java:
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import it.sauronsoftware.base64.Base64;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
public class Base64Utils {
private static final int CACHE_SIZE = 1024 ;
public static byte [] decode(String base64) throws Exception {
return Base64.decode(base64.getBytes( "UTF-8" ));
}
public static String encode( byte [] bytes) throws Exception {
return new String(Base64.encode(bytes));
}
public static String encodeFile(String filePath) throws Exception {
byte [] bytes = fileToByte(filePath);
return encode(bytes);
}
public static void decodeToFile(String filePath, String base64) throws Exception {
byte [] bytes = decode(base64);
byteArrayToFile(bytes, filePath);
}
public static byte [] fileToByte(String filePath) throws Exception {
byte [] data = new byte [ 0 ];
File file = new File(filePath);
if (file.exists()) {
FileInputStream in = new FileInputStream(file);
ByteArrayOutputStream out = new ByteArrayOutputStream( 2048 );
byte [] cache = new byte [CACHE_SIZE];
int nRead = 0 ;
while ((nRead = in.read(cache)) != - 1 ) {
out.write(cache, 0 , nRead);
out.flush();
}
out.close();
in.close();
data = out.toByteArray();
}
return data;
}
public static void byteArrayToFile( byte [] bytes, String filePath) throws Exception {
InputStream in = new ByteArrayInputStream(bytes);
File destFile = new File(filePath);
if (!destFile.getParentFile().exists()) {
destFile.getParentFile().mkdirs();
}
destFile.createNewFile();
OutputStream out = new FileOutputStream(destFile);
byte [] cache = new byte [CACHE_SIZE];
int nRead = 0 ;
while ((nRead = in.read(cache)) != - 1 ) {
out.write(cache, 0 , nRead);
out.flush();
}
out.close();
in.close();
}
}
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