String str = "hello"; 
String base64Encoded = Base64.encodeToString(str.getBytes()); 
String str2 = Base64.decodeToString(base64Encoded); 
Assert.assertEquals(str, str2);  

String str = "hello"; 
String base64Encoded = Hex.encodeToString(str.getBytes()); 
String str2 = new String(Hex.decode(base64Encoded.getBytes())); 
Assert.assertEquals(str, str2);  

String str = "hello"; 
String salt = "123"; 
String md5 = new Md5Hash(str, salt).toString();//还可以转换为 toBase64()/toHex()  

String str = "hello"; 
String salt = "123"; 
String sha1 = new Sha256Hash(str, salt).toString(); 

String str = "hello"; 
String salt = "123"; 
//内部使用MessageDigest 
String simpleHash = new SimpleHash("SHA-1", str, salt).toString();  

DefaultHashService hashService = new DefaultHashService(); //默认算法SHA-512 
hashService.setHashAlgorithmName("SHA-512"); 
hashService.setPrivateSalt(new SimpleByteSource("123")); //私盐，默认无 
hashService.setGeneratePublicSalt(true);//是否生成公盐，默认false 
hashService.setRandomNumberGenerator(new SecureRandomNumberGenerator());//用于生成公盐。默认就这个 
hashService.setHashIterations(1); //生成Hash值的迭代次数 
 
HashRequest request = new HashRequest.Builder() 
      .setAlgorithmName("MD5").setSource(ByteSource.Util.bytes("hello")) 
      .setSalt(ByteSource.Util.bytes("123")).setIterations(2).build(); 
String hex = hashService.computeHash(request).toHex();  

SecureRandomNumberGenerator randomNumberGenerator = 
   new SecureRandomNumberGenerator(); 
randomNumberGenerator.setSeed("123".getBytes()); 
String hex = randomNumberGenerator.nextBytes().toHex();  

AesCipherService aesCipherService = new AesCipherService(); 
aesCipherService.setKeySize(128); //设置key长度 
//生成key 
Key key = aesCipherService.generateNewKey(); 
String text = "hello"; 
//加密 
String encrptText =  
aesCipherService.encrypt(text.getBytes(), key.getEncoded()).toHex(); 
//解密 
String text2 = 
 new String(aesCipherService.decrypt(Hex.decode(encrptText), key.getEncoded()).getBytes()); 
Assert.assertEquals(text, text2);  

PasswordService/CredentialsMatcher

public interface PasswordService { 
  //输入明文密码得到密文密码 
  String encryptPassword(Object plaintextPassword) throws IllegalArgumentException; 
} 

public interface CredentialsMatcher { 
  //匹配用户输入的token的凭证（未加密）与系统提供的凭证（已加密） 
  boolean doCredentialsMatch(AuthenticationToken token, AuthenticationInfo info); 
} 

public class MyRealm extends AuthorizingRealm { 
  private PasswordService passwordService; 
  public void setPasswordService(PasswordService passwordService) { 
    this.passwordService = passwordService; 
  } 
   //省略doGetAuthorizationInfo，具体看代码  
  @Override 
  protected AuthenticationInfo doGetAuthenticationInfo(AuthenticationToken token) throws AuthenticationException { 
    return new SimpleAuthenticationInfo( 
        "wu", 
        passwordService.encryptPassword("123"), 
        getName()); 
  } 
} 

[main] 
passwordService=org.apache.shiro.authc.credential.DefaultPasswordService 
hashService=org.apache.shiro.crypto.hash.DefaultHashService 
passwordService.hashService=$hashService 
hashFormat=org.apache.shiro.crypto.hash.format.Shiro1CryptFormat 
passwordService.hashFormat=$hashFormat 
hashFormatFactory=org.apache.shiro.crypto.hash.format.DefaultHashFormatFactory 
passwordService.hashFormatFactory=$hashFormatFactory 
passwordMatcher=org.apache.shiro.authc.credential.PasswordMatcher 
passwordMatcher.passwordService=$passwordService 
myRealm=com.github.zhangkaitao.shiro.chapter5.hash.realm.MyRealm 
myRealm.passwordService=$passwordService 
myRealm.credentialsMatcher=$passwordMatcher 
securityManager.realms=$myRealm  

String algorithmName = "md5"; 
String username = "liu"; 
String password = "123"; 
String salt1 = username; 
String salt2 = new SecureRandomNumberGenerator().nextBytes().toHex(); 
int hashIterations = 2;  
SimpleHash hash = new SimpleHash(algorithmName, password, salt1 + salt2, hashIterations); 
String encodedPassword = hash.toHex();  

protected AuthenticationInfo doGetAuthenticationInfo(AuthenticationToken token) throws AuthenticationException { 
  String username = "liu"; //用户名及salt1 
  String password = "202cb962ac59075b964b07152d234b70"; //加密后的密码 
  String salt2 = "202cb962ac59075b964b07152d234b70"; 
SimpleAuthenticationInfo ai =  
    new SimpleAuthenticationInfo(username, password, getName()); 
  ai.setCredentialsSalt(ByteSource.Util.bytes(username+salt2)); //盐是用户名+随机数 
    return ai; 
} 

jdbcRealm.saltStyle=COLUMN 
jdbcRealm.authenticationQuery=select password, concat(username,password_salt) from users where username = ? 
jdbcRealm.credentialsMatcher=$credentialsMatcher 

[main] 
credentialsMatcher=org.apache.shiro.authc.credential.HashedCredentialsMatcher 
credentialsMatcher.hashAlgorithmName=md5 
credentialsMatcher.hashIterations=2 
credentialsMatcher.storedCredentialsHexEncoded=true 
myRealm=com.github.zhangkaitao.shiro.chapter5.hash.realm.MyRealm2 
myRealm.credentialsMatcher=$credentialsMatcher 
securityManager.realms=$myRealm 

public boolean doCredentialsMatch(AuthenticationToken token, AuthenticationInfo info) { 
    String username = (String)token.getPrincipal(); 
    //retry count + 1 
    Element element = passwordRetryCache.get(username); 
    if(element == null) { 
      element = new Element(username , new AtomicInteger(0)); 
      passwordRetryCache.put(element); 
    } 
    AtomicInteger retryCount = (AtomicInteger)element.getObjectValue(); 
    if(retryCount.incrementAndGet() > 5) { 
      //if retry count > 5 throw 
      throw new ExcessiveAttemptsException(); 
    } 
 
    boolean matches = super.doCredentialsMatch(token, info); 
    if(matches) { 
      //clear retry count 
      passwordRetryCache.remove(username); 
    } 
    return matches; 
}