“Hacker101 encrypted pastebin” likely refers to a CTF (Capture The Flag) challenge from Hacker101 (a free web security class by HackerOne) involving an encrypted pastebin-style web app. The challenge often tests your ability to exploit cryptographic weaknesses, not just SQLi or XSS.
The second flag often involves reaching a hidden "admin" or "debug" page by manipulating the encrypted data. hacker101 encrypted pastebin
If the server returns a specific error (e.g., "Invalid Padding") when you submit a modified ciphertext, it confirms it is checking the padding before processing the data. hacker101 encrypted pastebin