Blog
Yoroi Wallet: How the SecondFi Recovery Tool Returns Funds
Redacción CardumenEducation
What you knew as Yoroi wallet was renamed SecondFi in April 2026 and is no longer operating today. The team decided not to resume operations, and its current job is to return the funds of the people who were affected. The useful question is no longer what to do with your money, but how far along the refund is.
Two figures that must not be mixed. The official statement describes four draining events: three were carried out by external attackers and took 16.1M ADA from 374 addresses; the fourth is attributed to white-hats, and the company reports those funds as accessible and safeguarded. Separately, the emergency rescue measures secured around 129M ADA, directed to an independent custodian (a Fetch on-chain analysis puts the scope at close to 2,850 wallets). This article covers that second phase.
Who is who in the SecondFi recovery
| Actor | What it is | Why it matters |
|---|---|---|
| SecondFi | The wallet you knew as Yoroi, by EMURGO | It stopped operating; today it is the recovery team |
| zkSecurity | Independent audit firm | It audited the code of the recovery tool |
gnark |
Third-party cryptography library (Consensys) | That is where the two serious flaws were, not in the SecondFi code |
| CIP-1852 | Cardano’s credential derivation standard | It is the basis of the ZK proof |
What is ready and what is still missing in the recovery
The official update of September 15 splits the work into three fronts, and only one remains open:
- Platform: vulnerability patched and independent code reviews completed.
- Migration: tool v2 is live; it supports staked balances and covers the network fees of wallets without ADA.
- Asset recovery: the tool with ZK proofs is the pending piece, and it is precisely the one that will make it possible to recover funds.
The technical milestones already published: the ZK proof audit on September 9, the smart contract audit on September 11, and the refunds review started on September 14.
The official timeline, with a time-zone caveat
Mind the chart in the tweet: its dates are in Singapore time (SGT, UTC+8), so they do not match Chile time exactly.
| Date | Milestone (recovery block) | Status |
|---|---|---|
| 29 Jun | EMURGO recovery fund announced | ✅ Complete |
| 2 Jul | Checker for affected wallets | ✅ Complete |
| 9 Sep | Zero-knowledge proof audit finalised | ✅ Complete |
| 11 Sep | Smart contract audit finalised | ✅ Complete |
| 14 Sep | Refund review begins | 🟡 Under review |
| End of Sep | Tool launch (expected) | ⏳ Pending |
When the tool launches and what to do meanwhile
The published date is the end of September 2026, subject to the final review and the production checks. There is no specific day yet, and the team promised step-by-step guides before launch.
Meanwhile you can move your funds with tool v2, inside the official app or its extension: the step-by-step guide to migrate from Yoroi to SecondFi covers that process. The team recommends using a hardware wallet and comparing the full destination address, character by character, before confirming, because transfers cannot be reversed. If you are unsure whether your wallet is on the list, the official checker answers that first.
How funds are recovered without handing over your seed
A zero-knowledge proof (or ZK) lets you prove that you know something without revealing it. Here it serves one concrete purpose: proving that you control your Cardano wallet credential without exposing the private key or the derivation path.
The tool is user-initiated, meaning you decide when to start your Recovery Request, and it never asks for your seed phrase. Instead, a circuit proves that you know the master extended private key from which your credential is derived.
Cardano derives credentials under the CIP-1852 standard, along the path m/1852’/1815’/account’/role/index. The circuit takes the master key and the account, role and index values as private inputs (those never leave the browser), derives the credential, computes its hash and compares it against the only public input of the proof. If it matches, the proof validates without revealing keys or the derivation path.
Why the challenge was proving it in the browser
The system is Groth16: cheap to verify, expensive to prove. Its proving key weighs around 1.2 GiB, which is why the project includes seven patches to gnark and gnark-crypto. The goal is for you to generate the proof in your own browser, with your keys never travelling to a server.
What the zkSecurity audit found
zkSecurity was engaged on August 3, 2026, to audit Emurgo/proof-tool (commit ba065e6), with two consultants over two weeks. The zkSecurity audit report is free to read. Result: two high-severity findings and two low-severity findings.
The two serious ones were not in the SecondFi code
Both high findings were in the upstream code of the gnark library (v0.15.0), not in the project’s own repository: missing range checks in the carries of emulated field multiplication and at the output of operations used in Blake2b/SHA-512. In plain terms, a malicious prover could have claimed a victim’s public key from its own seed. Both were fixed by updating gnark to v0.16.3, via proof-tool PR#7, and the auditors reviewed it, tested it again and confirmed the fix.
The two open ones are not practically exploitable
Both low findings are in the project’s own repository and remain open, but the auditors assessed them as not practically exploitable. The overall conclusion is that the serious issues were in a third-party dependency and are now closed, while the open ones sit in the project’s own code with no practical impact. No high-severity finding remains pending.
What the community asks for and the company does not mention
In a sample of 24 reactions to the official tweets of September 9, 12 and 14, the most repeated topic is not the one the company communicates: nine are about NIGHT / Midnight tokens, and three more about the fees to redeem them. None of the three official tweets mentions NIGHT even once.
NIGHT and Midnight: airdrops 3 and 4 and the pending thaws
@midu97647902 (Sep 9) bundles three unanswered questions: “What about NIGHT token redeem? […] As I know we need some ADA to cover fees to redeem. There is still thaw 3 and 4!”. And @YUBYEONGCHAN (Sep 14) adds a concrete data point: the third unfreezing has already finished and its airdrop has not appeared.
The crux of the problem is that the tokens keep unlocking after the incident, so anyone migrating their ADA today may have future airdrops pointing at the old wallet.
The fee asymmetry
@yeck_ryan (Sep 9): “Why are you not covering the network fees for the night redemptions that can be claimed right now […] from compromised wallets with insufficient funds?” There is support for this in the announcements themselves: tool v2 does cover the network fees of the migration, and that same coverage is not announced for redemption. Redeeming requires ADA for the fee, and there are compromised wallets whose balance was left at zero.
The emotional summary came from @Chuntingkw95978 (Sep 9): “We just want the Ada back as promised.” The “99%” it mentions is rhetorical, not a measured figure.
How to spot scams at this stage
- Nobody will ask you for your seed or your private key. SecondFi states it explicitly: it never will. If they ask by DM, email or support chat, it is fraud.
- There is no separate migration app and no new site. Everything happens inside the app you already have or its extension.
- Urgency is the most telling signal. Official channels spoke of the end of September and of prior guides, and nobody legitimate will rush you.
Official channels: @secondfiapp and @secondfi_jp on X, the knowledge base and ticket support.
Open questions about the SecondFi refund
How much does the refund cover, and what does it include?
It is still unknown whether it covers only ADA or also tokens and NFTs, and how the amount per wallet is calculated. Everything points to the June 26 balance snapshot, but the team has not confirmed it.
Who pays the fees of the recovery?
Tool v2 does cover the network fees of the migration; that same coverage is not announced for the recovery. It is one of the questions the community repeats most.
What happens with NIGHT, Midnight and airdrops 3 and 4?
The tokens keep thawing: the schedule is published in the official Midnight FAQ — four equal installments of 25% spread over 360 days, with the first thaw falling on a random date between day 1 and day 90, and the redemption portal open for 450 days. What remains unanswered is who covers the fee for that redemption from the compromised wallets: SecondFi covered the network fees of the migration, but did not announce the same for NIGHT.
What role does Intersect play with the ~129M ADA recovered?
The custody of the secured funds remains under discussion, and it is also unclear how wallets with several accounts are handled.
About the Groom Lake report (engaged on June 27, results on July 20): it describes “potential indicators consistent with a state actor” and possible links to Lazarus. It is an unconfirmed finding, under evaluation, cited as it was published.
For the earlier context, review what happened in the SecondFi and Yoroi incident. And for the rest of your setup: Cardano wallet comparison and how to delegate your ADA.
Sources
- @secondfiapp — Recovery Progress and Timeline (Sep 15, 2026)
- @secondfiapp — Security Audit Update: Asset Recovery Tool (Sep 14, 2026)
- @secondfiapp — Migration Tool Update v2 (Sep 9, 2026)
- zkSecurity — Audit of SecondFi’s proof-tool circuits and gnark patches
- Emurgo/proof-tool — PR#7 (gnark v0.16.3)
- Official knowledge base · Wallet checker · Support
Sample of 24 comments under the official announcements of September 9, 12 and 14, 2026: this is not a survey.