Issue in encoding password with spring security

Question

I am using grails 2.3.0 and facing the weird issue when encoding the password with spring security:

This is my method to encode password:

String encodePassword(String password) {
    return springSecurityService.encodePassword(password)
}

and using like that

log.debug encodePassword("mkb")
log.debug encodePassword("mkb")
log.debug encodePassword("mkb")

I am encoding the same password several times and each time I am getting the different encoded password.

logs:

$2a$10$h8T4BxgOeozmH/VSPJl7NeTaF2P0iONpSdqDN7dDFFAG.sy8WG/8K
$2a$10$a7qybaiLF/eNrTSwFohjkezNaJTTDdMEinRYKjxDzEt.OoxaIgFOu
$2a$10$nZVhUT0QTmmbtt22CPtM..cLxU252RGBIMkd5aSd2AFXNTNLQ./6u

Answer 1

That's fine. Looks like you're using BCrypt password hash, this algorithm uses random salt each time you encode password (other hashing algorithms use a 'salt source property', like id). This salt is prepended to hash

So you have:

• $2a - salt version
• $10 - rounds
• $h8T4BxgOeozmH/VSPJl7NeTaF2P0iONpSdqDN7dDFFAG.sy8WG/8K - Base64 for salt+hash, where salt get first 24 characters, and hash takes the rest:
  • h8T4BxgOeozmH/VSPJl7NeTaF - salt
  • 2P0iONpSdqDN7dDFFAG.sy8WG/8K - hash (10 rounds for salt + password)

See Spring Security's BCrypt sources: https://github.com/spring-projects/spring-security/blob/master/crypto/src/main/java/org/springframework/security/crypto/bcrypt/BCrypt.java

If you need to check user password manually, you have to use passwordEncoder, like:

//dependency injection
def passwordEncoder

//validate
String enteredPassword = params.password
User user = ...
if (!passwordEncoder.isPasswordValid(user.password, enteredPassword, null)) { //validates raw password against hashed
   //... wrong password entered
}