I was given a [binary](https://github.com/mar232320/ctf-writeups/raw/main/nactf/2022/tracer) to reverse-engineer
I disassembled it in gdb at first but it looked like the flag was encryptedthe binary checks the user input with fgets() and strcmp() it with the decrypted flagI used ltace to trace the library calls. The flag wasn't visible entirely so I changed the string length parameter (-s 128) to see the full flag
# nactf{how_even_do_stream_ciphers_work_i_definitely_did_this_wrong}