BLT+L: Efficient Signatures from Timestamping and Endorsements

Denis Firsov, Henri Lakk, Sven Laur, and Ahto Truu



We propose a new digital signature scheme based on combining cryptographic timestamping with an endorsement scheme, both of which can be constructed from one-way and collision-resistant hash functions. The signature scheme is efficient and allows balancing of key generation and signing time for signature size and verification time. The security analysis is based on a realistic model of timestamping. As part of our construction, we introduce the novel concept of endorsements, which may be of independent interest.