Under the bridge [OC]
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.
It's a very short Python script and I'm confident I get the general idea - there's absolutely nothing related to current time in the decryption process. What they refer to as a "time lock" is just encrypting the key in a loop (so the encrypted key from one loop becomes the plain text for the next one) for the specified duration and then telling you how many iterations were done. That number then becomes a second part of the password - to decrypt, you simply provide the password and the number of iterations, nothing else matters.