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1

Yes you should be concerned about this. Its a possible side-channel and it reveals information about your system. Some possible defenses (that are being used) are: Use a pseudo random minimum wait delay. (this means that a valid or invalid response will take about the same amount of time) have an invalid response do all the calculation steps of a valid ...


1

I think that Linux uses some increasing delay for invalid logins. For example, if you login with a bad username or password, there's something like a 1 second delay on your first attempt, 2 seconds on your next attempt, 4 on your third, etc... This both hides the calculation delay that you are concerned with as well as slowing down people trying to mine your ...


-2

Usually it's not a problem that an attacker knows if login exists or not, so if you don't know if it's important for you then most likely it's not. But if you still want to hide the fact login is not exists then I would suggest to add some delay. Probably the best way will be to actually check some hash (and finally return 'false' anyway) so waiting time ...


1

You are correct @Numeron, the purpose of the \000 is to add a null to the end of the password stream (NULL value or END-OF-FILE value) since the null is an illegal character for a password (or any user input for that matter) it is used here to signify the end of the 'password' string (this is part of normal string behavior). the minor you see is comes ...


2

I continued my own investigation... \ is an escape character in java, but one thing I didn't realise is that it can escape more than one character. In this case, it escapes all three zeroes, thus adding a NUL character onto the string. This turns into an extra byte on the end of the UTF8 array, with value 0. This is presumably used by the algorithm to ...


2

The depicted design would entirely undermine the security of bcrypt. Your design could be simplified by simply eliminating the bcrypt part of the flow and rely only on the SHA hash. That simplification would not change the security of the design significantly, it would still be as insecure as simply applying a SHA hash. Using a SHA hash with a salt would ...


2

The risk here is that if an attacker manages to extract the SHA'd passwords from the database, then they can run a password guessing attack at a relatively fast speed. You should at least salt these password, but then you're increasing complexity which is generally at odds with security. A good secure system should be as simple as possible to make it so. I ...


6

Bcrypt is run many times to intentionally slow it down. Perhaps you need to adjust the number of rounds of bcrypt you are running? This answer has some information on it. While what you propose may work, I can't say that implementing a variant of standard password handling is a good idea. While I have specific concerns, such as the SHA hash staying in the ...



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