Hardy Index Quantum readiness benchmark

Why it moved · Why it moved

IOTA moved down after a search for layer-1 quantum work came up empty

Stated intent is no longer enough to hold the Debating floor, and IOTA's shipped post-quantum work protects credentials rather than coins.

The Hardy Index · Published 20 August 2026 · Every dated event below carries a primary source.

The short answer

IOTA now sits at Tier 5 in the index. On 15 August a search of the iotaledger improvement-proposal and node repositories returned no quantum-related item aimed at layer-1 signatures, so the deployment dimension fell by one point. Nothing about IOTA's code changed then. Only our reading of the evidence did.

What moved and why

IOTA previously held the Debating band on a stated intention to adopt quantum-resistant standards once they mature. Under the v1.2 rubric, intent alone no longer clears that floor. Debating asks for something you can point at: a proposal filed in the chain's own improvement process, or a public research programme, aimed at the signatures that protect mainnet funds.

We searched the iotaledger improvement-proposal and node repositories and found no quantum-related issue at all. IOTA's layer 1 has signed with Ed25519 since Chrysalis replaced the older Winternitz one-time signatures in 2021. Ed25519 is an elliptic-curve scheme, and elliptic-curve signatures are the exact thing a large fault-tolerant quantum computer would break.

Only the deployment dimension moves, from 2 to 1. The signature and standards readings are unchanged. Here is where the chain sits now:

Where this stands today

  • IOTA 5 Exposed Hardy 18.5 of 100

As rated by the Hardy Index, current as of 2 October 2026. Ratings change when the evidence does, and every change is recorded in the changelog.

The layer-1 signature scheme in IOTA's own words

  1. TIP-0009 specifies Ed25519 as the signature scheme for IOTA layer-1 transactions, replacing the earlier Winternitz one-time signature design. source

What this does not mean

It does not mean IOTA has done no post-quantum work. It has, and the work is real. IOTA Identity v1.7 supports ML-DSA, SLH-DSA and Falcon, three of the lattice- and hash-based schemes coming out of the NIST standards process, including hybrid combinations with EdDSA.

But IOTA Identity secures verifiable credentials: digital attestations about who someone is or what they are entitled to. It does not sign token transfers. A credential signed with ML-DSA and a transaction signed with Ed25519 live in different parts of the stack. Protecting the first does not protect the second.

  • No IOTA mainnet funds are moved by a post-quantum signature today.
  • No known machine can break Ed25519 today. This is about the direction of travel, not an active exploit.
  • Nothing in IOTA's code changed. Our evidence bar changed, and IOTA no longer clears it.
  • A downgrade is reversible. A filed proposal aimed at layer-1 signatures would move it back.

Declared judgement callThis is a close placement. A reader who counts the Foundation's demonstrated post-quantum capability in Identity as evidence of intent toward layer 1 would reasonably leave IOTA in the Debating band. We record the disagreement rather than hide it.

If you hold IOTA

Nothing here asks you to do anything today. Your coins are secured by the same scheme they were secured by last week.

What to watch is narrow and checkable: a quantum-related item appearing in the iotaledger improvement-proposal repository that names layer-1 signatures. That is the single signal that would move this rating back up. Announcements about IOTA Identity, however substantial, will not, because they address a different layer.

If you want the longer history of why the market's "quantum-safe IOTA" label stopped matching the code, we covered it in why we rate IOTA the way we do. For the general question of what breaks and when, see Q-Day: when will quantum break crypto. The full entry is in the changelog.

Where to go next

  • IOTA: the full rating Every dimension score, with the source behind each one, and what the rating means if you hold it.
  • Is my crypto safe from quantum computers? If you have seen the scary headlines about quantum computers and crypto, here is the calm version. What is true, what it means for the coins you hold, and what is worth doing about it.
  • Which crypto is quantum proof? Plenty of projects call themselves quantum proof. Here is the independently checked version, and why the phrase itself is worth handling carefully.
  • Which is the most quantum-resistant blockchain? One question, one answer, with the working shown. This page is a summary of the Hardy Index, which is the live ranking behind it.

Sources

Every dated event above carries its own primary source. These are those sources, each checked on the date shown.

  1. iotaledger/tips issue tracker IOTA Foundation on GitHub · primary · checked 20 August 2026
  2. TIP-0009: Ed25519 Signature Scheme IOTA Foundation on GitHub · primary · checked 20 August 2026
  3. IOTA Identity: post-quantum signatures how-to IOTA documentation · primary · checked 20 August 2026

This is a security-readiness assessment, not investment advice.