A password-reset token you can predict
25 points · about 45 minutes · flag formatDC{...}Brief
Cryptography fails far more often from misuse than from broken maths — a predictable random value, a token signed with a guessable key, a hash used where a MAC was needed, an oracle that leaks one bit at a time. The primitive may be sound; the way it is wired is not.
This lab: A password-reset token you can predict. Break the guarantee a weak or misused primitive was meant to give.
Work it against your own copy of the target. When you have the flag, submit it below.
Objective
Find where a cryptographic value can be predicted, forged or unwound, and use that weakness to reach protected data. Capture the flag it guards.
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Sign inWalkthrough
Locked until you solve it — or reveal it above, which forfeits the points. 3 hints available before then.