如何在数据库中存储加密的密码？

Question

I am trying to store the password into the database in the encrypted form with the help of JSP and Servlets. How I can do that?

Answer 1

Self-written algorithms are a security risk, and painful to maintain.
MD5 is not secure .

Use the bcrypt algorithm, provided by jBcrypt (open source):

// Hash a password
String hashed = BCrypt.hashpw(password, BCrypt.gensalt());

// Check that an unencrypted password matches or not
if (BCrypt.checkpw(candidate, hashed))
    System.out.println("It matches");
else
    System.out.println("It does not match");

If you use Maven, you can get the library by inserting the following dependency in your pom.xml (if a newer version is available please let me know) :

<dependency>
    <groupId>de.svenkubiak</groupId>
    <artifactId>jBCrypt</artifactId>
    <version>0.4.1</version>
</dependency>

Answer 2

Try something like this to encrypt your data.

MessageDigest md = MessageDigest.getInstance("MD5");


......


synchronized (md) {

md.reset(); 
byte[] hash = md.digest(plainTextPassword.getBytes("CP1252"));

StringBuffer sb = new StringBuffer();
for (int i = 0; i < hash.length; ++i) {
sb.append(Integer.toHexString((hash[i] & 0xFF) | 0x100).toUpperCase().substring(1, 3));
}

String password = sb.toString();
}

Answer 3

You can also use something like below. Below is a crypt method which takes a string input and will return and encrypted string. You can pass password to this method.

public static String crypt(String str) {
    if (str == null || str.length() == 0) {
        throw new IllegalArgumentException(
                "String to encrypt cannot be null or zero length");
    }

    StringBuffer hexString = new StringBuffer();

    try {
        MessageDigest md = MessageDigest.getInstance("MD5");
        md.update(str.getBytes());
        byte[] hash = md.digest();

        for (int i = 0; i < hash.length; i++) {
            if ((0xff & hash[i]) < 0x10) {
                hexString.append("0"
                        + Integer.toHexString((0xFF & hash[i])));
            } else {
                hexString.append(Integer.toHexString(0xFF & hash[i]));
            }
        }
    } catch (NoSuchAlgorithmException e) {

    }

    return hexString.toString();
}