<span style="font-size:14px;">为了更好的用户体验,移动APPclient一般都会将用户信息进行保存以便兴许能够自己主动登录.</span>

保存了用户信息便涉及到了安全问题.

解决办法大概有一下几种:

1.首先,假设client和服务端都是你来设计开发,那么有两种比較可靠的方案

A.client将passwordHash加密,登录成功后将hash值保存到Sqlite.服务端得到username和hash值,採用相同的算法对password进行Hash运算,然后和用户传来的hash值进行比較,一致则登录成功.更加可靠的是对password加盐加密.比如能够採用PBKDF2加盐加密.

<span style="font-size:14px;">public static String createHash(String password)throws NoSuchAlgorithmException, InvalidKeySpecException {return createHash(password.toCharArray());}/*** Returns a salted PBKDF2 hash of the password.* * @param password*            the password to hash* @return a salted PBKDF2 hash of the password*/public static String createHash(char[] password)throws NoSuchAlgorithmException, InvalidKeySpecException {// Generate a random saltSecureRandom random = new SecureRandom();byte[] salt = new byte[SALT_BYTE_SIZE];random.nextBytes(salt);// Hash the passwordbyte[] hash = pbkdf2(password, salt, PBKDF2_ITERATIONS, HASH_BYTE_SIZE);return PBKDF2_ITERATIONS + ":" + toHex(salt) + ":" + toHex(hash);}</span>

加密后的字符串为1000:1507039de0a3c2c88ddf896233278e37d05fd8a0fadc570d:99222374678d4afe5d7d9bf9be4786e17f045ac217c6a2ca,

1000为迭代的次数,后面各自是salt和hash值.

服务端得到这个字符串后,从中解析出迭代次数,salt,hash1值,然后採用相同的算法对数据库里面的password进行计算

    public static boolean validatePassword(String password, String correctHash)throws NoSuchAlgorithmException, InvalidKeySpecException {return validatePassword(password.toCharArray(), correctHash);}/*** Validates a password using a hash.* * @param password*            the password to check* @param correctHash*            the hash of the valid password* @return true if the password is correct, false if not*/public static boolean validatePassword(char[] password, String correctHash)throws NoSuchAlgorithmException, InvalidKeySpecException {// Decode the hash into its parametersString[] params = correctHash.split(":");int iterations = Integer.parseInt(params[ITERATION_INDEX]);byte[] salt = fromHex(params[SALT_INDEX]);byte[] hash = fromHex(params[PBKDF2_INDEX]);// Compute the hash of the provided password, using the same salt,// iteration count, and hash lengthbyte[] testHash = pbkdf2(password, salt, iterations, hash.length);// Compare the hashes in constant time. The password is correct if// both hashes match.return slowEquals(hash, testHash);}

假设hash2和hash1一致,则登录成功.同一时候client将加密后的字符串保存到本地数据库,下次登录时直接从数据库读取.

B.使用非对称加密算法对password进行加密.

1. client使用公钥加密password，得到加密串，然后将其发送到服务端．
2. 服务端使用私钥解密password。进行验证，
3. 登录成功后，client将加密串保存到本地，便于下次自己主动登录；

android中使用jni对字符串加解密实现分析

加盐password哈希：怎样正确使用