def generate_proof_of_work_key(initial_key, time_seconds):
    proof_key = initial_key
    end_time = time.time() + time_seconds
    iterations = 0
    while time.time() < end_time:
        proof_key = scrypt(proof_key, salt=b'', N=SCRYPT_N, r=SCRYPT_R, p=SCRYPT_P, key_len=SCRYPT_KEY_LEN)
        iterations += 1
    print(f"Proof-of-work iterations (save this): {iterations}")
    return proof_key


def generate_proof_of_work_key_decrypt(initial_key, iterations):
    proof_key = initial_key
    for _ in range(iterations):
        proof_key = scrypt(proof_key, salt=b'', N=SCRYPT_N, r=SCRYPT_R, p=SCRYPT_P, key_len=SCRYPT_KEY_LEN)
    return proof_key

The first function is used during the encryption process, and the while loop clearly runs until the specified time duration has elapsed. So encryption would take 5 days no matter how fast your computer is, and to decrypt it, you'd have to do the same number of iterations your computer managed to do in that time. So if you do the decryption on the same computer, you should get a similar time, but if you use a different computer that is faster at doing these operations, it will decrypt it faster.