Base64... is actually plaintext; that's much, much worse.
I have to wonder how they sourced their developers. I don't think researchers would be motivated to do much more then post a low bidding ad on craigslist, meaning the quality of the developers will be commiserate.
They used 2 tier of payment to see if the payment had an effect on the security of the code.
> Final Study For the final study we recruited freelancers via direct messages. We searched for all freelancers and filtered for the skill “Java.” Unfortunately, Freelancer.com’s search function also returns JavaScript developers or developers where we saw no connection to Java, so we manually pruned out developers whose profile did not include Java skills. Based on our experience in the pre-studies we added two payment levels to our study design (EUR100 and EUR200). We only accepted freelancers’ submissions if they were functional
It's also interesting because 6 used an encryption algorithm, 10 used MD5 which is as good as plaintext nowadays IMO, and 8 used Base64, so even though 24 people thought they "secured it" the passwords are trivial to recover.