Re: [bitcoindev] One Time Signatures as an Advantage?

[Jason Resch <jasonresch@gmail.com>]

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On Thu, May 21, 2026, 5:54 AM Mikhail Kudinov <mkudinov@blockstream.com>
wrote:

> Stateful hash-based schemes have been recommended by NIST. See
> https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-208.pdf
> .
>

Is the intention that these recommendations will eventually lead to full
standardization and FIPS compliance?

Will Bitcoin wait for that do you think, or will it lead in adopting
something like SHRINCS first and then NIST will follow in certifying what
would by then have become a de facto standard?

Also you might be interested to read about SHRINCS:
> https://delvingbitcoin.org/t/shrincs-324-byte-stateful-post-quantum-signatures-with-static-backups/2158
> .
>


I learned of SHRINCS just after making my post. I think it provides the
best of both worlds: short signatures in the general case when state is
available + the flexibility to fall back and sign many times in case state
is lost or the stateful key is used too many times.

In terms of PQC algorithms I'm aware of, this one seems to be among the
best in terms of its conservative security assumptions and compactness, and
the flexibility to sign many times when necessary addresses the problem
with public donation addresses.

Jason



>
> On Wed, May 20, 2026 at 7:44 PM Jason Resch <jasonresch@gmail.com> wrote:
>
>> 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.
>>
>> SLH-DSA (for parameters n=16, w=16) results in signatures that are 7,888
>> bytes long.
>>
>> However, if statelessness isn't required, and this can be reduced to 900
>> bytes for something like XMSS using the same parameters.
>>
>> 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.
>>
>> 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.
>>
>> 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.
>>
>> 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.
>>
>> Jason
>>
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