If a block has much fewer transactions than average, let’s say 63 like 4MB block 774628, will keys have less probability to falsely match against its BIP157-8 compact filter?

2 Answers 2


No, BIP158 basic filters have a fixed false positive rate of exactly 1/784931, regardless of how many elements they contain.


Just ftr. The 1/784931 fpr is for bitcoin core and compatible. Wasabi filter's parameters are different because Wasabi wallets are expected to have more keys than average bitcoin core wallets given coinjoins and remixes.

  • Wasabi doesn't use BIP158 filters. Feb 5, 2023 at 19:56
  • @PieterWuille Wasabi does use BIP158 filters AFAIU. docs.wasabiwallet.io/FAQ/… docs.wasabiwallet.io/using-wasabi/BIPs.html
    – yahiheb
    Feb 5, 2023 at 23:48
  • Well BIP158 specifies the parameters for the filter, including the 1/784931 false positive rate. It's possible it uses a (very) similar design, but IIRC at least the filter contents is different, and the parameters are different. Feb 6, 2023 at 2:07
  • Thank you for clarifying this.
    – yahiheb
    Feb 6, 2023 at 15:02

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.