Are the target key, k_image tx pub unique and no repetitions in all blockchain?


1 Answer 1


Yes, they are unique - see this answer.

I = xHp(P)

As x and P refer to one-time keys, and that the key image is used to determine if an output is spent, they have to be unique (thus only appear once in the blockchain).

  • In order not to produce another topic, I will ask a question here. Was there any question about being able to scan backwards from the highest point to the lowest point to speed up getting the closest possible transactions? And what are the downsides to this? Feb 6, 2021 at 7:01
  • "scan" in what context? seems like an unrelated question as key images are a double spend protection for which there isn't a "scan" so to speak, it's an O(1) lookup. "scanning" usually refers to scanning blocks for outputs destined to ones wallet (i.e. checking for incoming transactions).
    – jtgrassie
    Feb 6, 2021 at 12:47
  • Yes, the question is not connected, I decided not to make an additional topic simply, and probably I incorrectly described the idea. I will try again. I have my view key and spend key, I do not want to sync for a long time, but I want to know about the funds that I have now. I take the upper block and go from it to the lower one, is this possible? Feb 6, 2021 at 14:14
  • Unrelated questions should be new questions. Especially so given the restricted length of comment field.
    – jtgrassie
    Feb 7, 2021 at 3:13

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