Table 1 Performance and security comparison of OTS schemes
Average size | Average timing (evaluation times of underlying hash function) | Security level | |||||
|---|---|---|---|---|---|---|---|
Scheme | Signature key | Verification key | Signature | Gen | Sig | Ver | |
Lampot OTS | 2nk | 2nk | nk | 2Â k | 0 | k | n |
Merkle OTS | \(\left( {k + \left\lfloor {\log \,k} \right\rfloor + 1} \right)n\) | \(\left( {k + \left\lfloor {\log \,k} \right\rfloor + 1} \right)n\) | \(\left( {\frac{k}{2} + \left\lfloor {\log \,k} \right\rfloor + 1} \right)n\) | \(k + \left\lfloor {\log \,k} \right\rfloor + 1\) | 0 | \(\frac{k}{2} + \left\lfloor {\log \,k} \right\rfloor + 1\) | n |
Winternitz OTS | ln | ln | ln | l(w–1) | \(\frac{{l\left( {w{-}1} \right)}}{2}\) | \(\frac{{l\left( {w{-}1} \right)}}{2}\) | n–w–1–2log(lw) |
WOTS +  | ln | (l + w–1)n | ln | l(w–1) | \(\frac{{l\left( {w{-}1} \right)}}{2}\) | \(\frac{{l\left( {w{-}1} \right)}}{2}\) | n–log(w2l + w) |