Java常見加密和解密演算法
阿新 • • 發佈：2018-12-11
1:加密和解密輔助工具類:
/** * byte hex utility class **/ public class ByteHexUtils { private static final String HEX_STR = "0123456789ABCDEF"; /** * @param hex * @return */ public static byte[] hex2Bytes(String hex) { ByteBuffer bf = ByteBuffer.allocate(hex.length() / 2); for (int i = 0; i < hex.length(); i++) { String hexStr = hex.charAt(i) + ""; i++; hexStr += hex.charAt(i); byte b = (byte) Integer.parseInt(hexStr, 16); bf.put(b); } return bf.array(); } /** * @param bytes **/ public static String bytes2Hex(byte[] bytes) { String result = ""; String hex = ""; for (int i = 0; i < bytes.length; i++) { //位元組高4位 hex = String.valueOf(HEX_STR.charAt((bytes[i] & 0xF0) >> 4)); //位元組低4位 hex += String.valueOf(HEX_STR.charAt(bytes[i] & 0x0F)); result += hex; //+" " } return result; } }
2:Base64加密和解密:
/** * base64 utility class **/ import sun.misc.BASE64Decoder; import sun.misc.BASE64Encoder; public class Base64Utils { /** * byte to base64 **/ public static String encode(byte[] bytes) { BASE64Encoder base64Encoder = new BASE64Encoder(); return base64Encoder.encode(bytes); } /** * base64 to byte **/ public static byte[] decode(String base64) throws IOException { BASE64Decoder base64Decoder = new BASE64Decoder(); return base64Decoder.decodeBuffer(base64); } public static void main(String[] args) throws IOException { final String testString = "hello,i am chenkangxian,good night!"; System.out.println(Base64Utils.encode(testString.getBytes())); String base64Str = "aGVsbG8saSBhbSBjaGVua2FuZ3hpYW4sZ29vZCBuaWdodCE="; System.out.println(new String(Base64Utils.decode(base64Str), Charset.defaultCharset())); } }
3:SHA1和MD5加密和解密:
/** * digest utility class with MD5 and SHA-1 **/ public static class DigestsUtils { /** * 160位(16進位制字串: 40) **/ private static final String SHA1 = "SHA-1"; /** * 128位(16進位制字串: 32) **/ private static final String MD5 = "MD5"; /** * SHA-1; encrypt without (salt and iterations) * * @param bytes encrypt byte array **/ public static byte[] sha1(byte[] bytes) { return digest(bytes, SHA1, (byte[]) null, 1); } /** * SHA-1; encrypt without iterations * * @param bytes encrypt byte array * @param salt encrypt salt **/ public static byte[] sha1(byte[] bytes, byte[] salt) { return digest(bytes, SHA1, salt, 1); } /** * SHA-1; * * @param bytes encrypt byte array * @param salt encrypt salt * @param iterations encrypt iterations **/ public static byte[] sha1(byte[] bytes, byte[] salt, int iterations) { return digest(bytes, SHA1, salt, iterations); } /** * MD5 **/ public static byte[] md5(byte[] bytes) { return digest(bytes, MD5, (byte[]) null, 1); } /** * MD5 **/ public static byte[] md5(byte[] bytes, byte[] salt) { return digest(bytes, MD5, salt, 1); } /** * MD5 **/ public static byte[] md5(byte[] bytes, byte[] salt, int iterations) { return digest(bytes, MD5, salt, iterations); } /** * 對salt生成的位元組是平臺預設編碼 * * @see Charset#defaultCharset() **/ public static byte[] generateSalt() { return UUID.randomUUID().toString().getBytes(); } /** * digest encode md5 * * @param newStr new str * @param oldMd5 old md5 bytes * @param salt md5 salt * @param iterations md5 digest iterations * @see Arrays **/ public static boolean decodeMd5(byte[] newStr, byte[] oldMd5, byte[] salt, int iterations) { return decode(MD5, newStr, oldMd5, salt, iterations); } /** * digest encode sha-1 * * @param newStr new str * @param oldSha1 old sha-1 bytes * @param salt sha-1 salt * @param iterations sha-1 digest iterations * @see Arrays **/ public static boolean decodeSha1(byte[] newStr, byte[] oldSha1, byte[] salt, int iterations) { return decode(SHA1, newStr, oldSha1, salt, iterations); } /** * digest encode * * @param newStr new str * @param oldDigest old digest bytes * @param salt md5 salt * @param iterations md5 digest iterations * @see Arrays **/ private static boolean decode(String algorithm, byte[] newStr, byte[] oldDigest, byte[] salt, int iterations) { if (MD5.equalsIgnoreCase(algorithm)) { byte[] newDigest = md5(newStr, salt, iterations); log.debug("encode new md5 digest: {}", ByteHexUtils.bytes2Hex(newDigest)); if (Arrays.equals(newDigest, oldDigest)) { return true; } else { return false; } } else { byte[] newDigest = sha1(newStr, salt, iterations); log.debug("encode new sha1 digest: {}", ByteHexUtils.bytes2Hex(newDigest)); if (Arrays.equals(newDigest, oldDigest)) { return true; } else { return false; } } } /** * digest with salt and iterations **/ private static byte[] digest(byte[] bytes, String algorithm, byte[] salt, int iterations) { try { MessageDigest e = MessageDigest.getInstance(algorithm); if (salt != null) { e.update(salt); } byte[] result = e.digest(bytes); for (int i = 1; i < iterations; ++i) { e.reset(); result = e.digest(result); } return result; } catch (GeneralSecurityException e) { e.printStackTrace(); } return null; } public static void main(String[] args) { String testString = "123456"; String salt = UUID.randomUUID().toString(); byte[] md5 = DigestsUtils.md5(testString.getBytes(), salt.getBytes(), 1); System.out.println(ByteHexUtils.bytes2Hex(md5)); if (DigestsUtils.decodeMd5("123456".getBytes(), md5, salt.getBytes(), 1)) { System.out.println("密碼正確"); } else { System.out.println("密碼錯誤"); } byte[] sha1 = DigestsUtils.sha1(testString.getBytes()); System.out.println(ByteHexUtils.bytes2Hex(sha1)); if (DigestsUtils.decodeSha1("123456".getBytes(), sha1, null, 1)) { System.out.println("密碼正確"); } else { System.out.println("密碼錯誤"); } } }
4:RSA加密和解密
在這裡插入程式碼片
``` /**
* rsa utility class
**/
public static class RsaUtils {
private static final String RSA = "RSA";
//生成公鑰和私鑰
/**
* 首先初始化{@link KeyPairGenerator},並生成{@link KeyPair},
* 得到{@link KeyPair},便可以通過getPublic和getPrivate分別獲取
* 公鑰和私鑰.為了方便儲存,將其使用Base64編碼轉換為String型別的列印字元
**/
public static KeyPair getKeyPair() throws Exception {
KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance(RSA);
//預設512,如果是1024位,需要到官網下載不限長度的加密jar包
keyPairGenerator.initialize(512);
KeyPair keyPair = keyPairGenerator.generateKeyPair();
return keyPair;
}
/**
* get public key
*
* @see Base64Utils#encode(byte[])
**/
public static String getPublicKeyStr(KeyPair keyPair) {
PublicKey publicKey = keyPair.getPublic();
byte[] bytes = publicKey.getEncoded();
return Base64Utils.encode(bytes);
}
/**
* get primary key
*
* @see Base64Utils#encode(byte[])
**/
public static String getPrivateKeyStr(KeyPair keyPair) {
PrivateKey privateKey = keyPair.getPrivate();
byte[] bytes = privateKey.getEncoded();
return Base64Utils.encode(bytes);
}
/**
* 將String型別的金鑰轉換為PublicKey和PrivateKey物件
**/
public static PublicKey string2PublicKey(String publicKeyStr) throws Exception {
byte[] keyBytes = Base64Utils.decode(publicKeyStr);
//使用ASN.1為公鑰編碼
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(RSA);
PublicKey publicKey = keyFactory.generatePublic(keySpec);
return publicKey;
}
/**
* 將String型別的金鑰轉換為{@link PrivateKey}
**/
public static PrivateKey string2PrivateKey(String privateKeyStr) throws Exception {
byte[] keyBytes = Base64Utils.decode(privateKeyStr);
//使用ASN.1為私鑰編碼
PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(RSA);
PrivateKey privateKey = keyFactory.generatePrivate(keySpec);
return privateKey;
}
/**
* 使用公鑰加密
**/
public static byte[] publicEncrypt(byte[] content, PublicKey publicKey) throws Exception {
Cipher cipher = Cipher.getInstance(RSA);
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
byte[] bytes = cipher.doFinal(content);
return bytes;
}
/**
* 使用私鑰解密
**/
public static byte[] privateDecrypt(byte[] content, PrivateKey privateKey) throws Exception {
Cipher cipher = Cipher.getInstance(RSA);
cipher.init(Cipher.DECRYPT_MODE, privateKey);
byte[] bytes = cipher.doFinal(content);
return bytes;
}
public static void main(String[] args) throws Exception {
final String testString = "1234567";
//獲得金鑰對
KeyPair keyPair = RsaUtils.getKeyPair();
//獲得私鑰字串
String privateKeyStr = RsaUtils.getPrivateKeyStr(keyPair);
System.out.println("primary key string: " + privateKeyStr);
System.out.println();
//獲得公鑰字串
String publicKeyStr = RsaUtils.getPublicKeyStr(keyPair);
System.out.println("public key string: " + publicKeyStr);
System.out.println();
//獲取私鑰和公鑰
PublicKey publicKey = RsaUtils.string2PublicKey(publicKeyStr);
PrivateKey privateKey = RsaUtils.string2PrivateKey(privateKeyStr);
System.out.println();
//使用公鑰加密
byte[] bytes = RsaUtils.publicEncrypt(testString.getBytes(), publicKey);
System.out.println("RSA公鑰加密: " + Base64Utils.encode(bytes));
System.out.println();
//使用私鑰解密
System.out.println("RSA私鑰解密: " + new String(RsaUtils.privateDecrypt(bytes, privateKey),
Charset.defaultCharset()));
}
}