XORed Gate

You found a small program guarding a gate. When run, the program prompts:
Enter the secret password to open the gate
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If the correct password is provided, the program prints the flag in the format ProblemStack{...}. The author has hidden both the flag and the password inside the binary using a straightforward XOR with a short repeating key.

Your task: analyze the binary (static analysis or simple extraction), find the obfuscated data (ciphertext and key), decode it, then run the program with the discovered password to produce the flag.