Preimage
Cryptography● Common
The original input to a hash function that produces a specific output. In HTLCs, the payment secret that when revealed allows claiming funds. Finding preimages for SHA-256 without the original is computationally infeasible.
Technical Notes
HTLC: hash(preimage) committed; revealing preimage claims payment. Preimage resistance: cannot find x given H(x). Second preimage resistance: given x, cannot find x' where H(x) = H(x'). Both properties hold for SHA-256.
Metadata
Visibility: Public
Created:1/3/2026by System