NIST is standardizing SLH-DSA as a stateless, post-quantum-secure hash-based signature scheme. However, to achieve the stateless feature of being able to sign multiple messages, requires a significant size overhead.<div><br /></div><div>SLH-DSA (for parameters n=16, w=16) results in signatures that are 7,888 bytes long.</div><div><br /></div><div>However, if statelessness isn't required, and this can be reduced to 900 bytes for something like XMSS using the same parameters.</div><div><br /></div><div>Furthermore, if multiple signings per key are dropped as a requirement, and "one time signatures" are used (e.g. WOTS+) then this size reduces further to 560 bytes.</div><div><br /></div><div>This is a ~14× reduction in signature size for a feature that Bitcoin transactions not only don't need, but are strongly discouraged if not harmful. Using the same key more than once is only required if one is reusing the same address (discouraged), or if one is attempting some kind of double-spend attack.</div><div><br /></div><div>This could be seen as a sort of advantage: if one attempts to double-spend, they may expose their private key. This same property was an element of Chaum's digital cash: attempting to double-spend exposed you.</div><div><br /></div><div>Is there any advocacy for NIST to standardize stateful or one-time-use signature algorithms? They seem well-suited to the block-chain use case, where there is always global and persistent state, and keys ought not be re-used. Though this needs to be carefully managed by wallet software: to only expose a one-time-use address to handle a single transaction with a single payer, and never use a OTS address for any kind of public-facing or long-term donation address. Perhaps this complication makes OTS not worth introducing generally, but their space saving properties are attractive.</div><div><br /></div><div>Jason</div>

<p></p>

-- <br />
You received this message because you are subscribed to the Google Groups &quot;Bitcoin Development Mailing List&quot; group.<br />
To unsubscribe from this group and stop receiving emails from it, send an email to <a href="mailto:bitcoindev+unsubscribe@googlegroups.com">bitcoindev+unsubscribe@googlegroups.com</a>.<br />
To view this discussion visit <a href="https://groups.google.com/d/msgid/bitcoindev/d3648bd4-03d3-4b98-92bf-d845302be349n%40googlegroups.com?utm_medium=email&utm_source=footer">https://groups.google.com/d/msgid/bitcoindev/d3648bd4-03d3-4b98-92bf-d845302be349n%40googlegroups.com</a>.<br />