BCrypt.checkpw() Invalid salt version exception

Question

I'm trying to implement authentication using BCrypt, in my Play 2.1. Java application, but I'm getting Invalid salt version exception when I'm trying to authenticate the user.

This is my stack trace

play.api.Application$$anon$1: Execution exception[[IllegalArgumentException: Invalid salt version]]
at play.api.Application$class.handleError(Application.scala:289) ~[play_2.10.jar:2.1.0]
at play.api.DefaultApplication.handleError(Application.scala:383) [play_2.10.jar:2.1.0]
at play.core.server.netty.PlayDefaultUpstreamHandler$$anon$2$$anonfun$handle$1.apply(PlayDefaultUpstreamHandler.scala:132) [play_2.10.jar:2.1.0]
at play.core.server.netty.PlayDefaultUpstreamHandler$$anon$2$$anonfun$handle$1.apply(PlayDefaultUpstreamHandler.scala:128) [play_2.10.jar:2.1.0]
at play.api.libs.concurrent.PlayPromise$$anonfun$extend1$1.apply(Promise.scala:113) [play_2.10.jar:2.1.0]
at play.api.libs.concurrent.PlayPromise$$anonfun$extend1$1.apply(Promise.scala:113) [play_2.10.jar:2.1.0]
java.lang.IllegalArgumentException: Invalid salt version
at org.mindrot.jbcrypt.BCrypt.hashpw(BCrypt.java:664) ~[jbcrypt-0.3m.jar:na]
at org.mindrot.jbcrypt.BCrypt.checkpw(BCrypt.java:763) ~[jbcrypt-0.3m.jar:na]
at model.operations.DistrictOperations.authenticate(DistrictOperations.java:24) ~[na:na]
at controllers.Application.authenticateDistrict(Application.java:26) ~[na:na]
at Routes$$anonfun$routes$1$$anonfun$applyOrElse$2$$anonfun$apply$2.apply(routes_routing.scala:133) ~[na:na]
at Routes$$anonfun$routes$1$$anonfun$applyOrElse$2$$anonfun$apply$2.apply(routes_routing.scala:133) ~[na:na]

I'm using following maven repository: http://mvnrepository.com/artifact/org.mindrot/jbcrypt/0.3m

My code is based on the documentation, thus

district.setPassword(BCrypt.hashpw(json.findPath("password").getTextValue(), BCrypt.gensalt()));    

For saving the password (I'm also checking the password for being null)

BCrypt.checkpw(password, d.getPassword());

For checking if the entered password is correct, where password is String and d.getPassword() is hashed password.

I don't know if this is relevant information, but to be precise I'm using hibernate for ORM and PostgreSQL 8.4 as DB.

I'm kind of stuck in here so I'm asking if anyone could help me out. Than you very much in advance.

Answer 1

For others encountering the same exception, check that you have the BCrypt.checkpw parameters the right way round. (I didn't and therefore found this question before I realised my silly mistake.)

Or as the OP answered himself, log/debug the value of the hashed password to double check you are actually comparing a hashed password! It should be a 60-char string in the format $2a$10$llw0G6IyibUob8h5XRt9xuRczaGdCm/AiV6SSjf5v78XS824EGbh.