SIGIL
Design partners for 2027Know which agent. Know who sent it. Know what it may do.
AI agents are starting to log in, check balances and pay on customers' behalf. SIGIL gives each agent a signed mandate, checks every request against it in milliseconds and keeps a tamper-evident record of what the agent did.
Agents don't click.
Banks have always read intent from a person at a screen: a login, a password, a tap to confirm. An agent does none of that.
When an agent pays, that old proof of intent disappears. The bank is left with a question it cannot yet answer: who authorised this, and for what?
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Major US banks report finding unvetted third-party AI agents inside customer accounts and move to restrict them.
Axios, via Yahoo Finance -
In a BioCatch survey of 1,440 bank fraud, AML and risk leaders in 25 countries, 84% named AI agents the industry's greatest exploitable weakness for the year ahead.
BioCatch press release -
Visa launched its Agentic Ready programme for Europe, including the UK, with 21 card issuers taking part from the start.
Visa press release
A mandate check, step by step.
Pick a request. SIGIL verifies the agent, the customer behind it and the mandate, then decides. Every name and figure here is synthetic.
Mandate M-0193
- Agent
- Trip planner, from Example Travel AI
- Acting for
- Ana Novak, current account ending 4471
- May
- Book travel: rail, flights and hotels
- Limits
- €900 per booking, €2,000 per month
- Used
- €606 this month
- Merchants
- EU and UK
- Valid until
- 31 December 2026
Signed with Ana's passkey on 1 Nov 2026 at 18:42. Agent key ed25519:9f1c…a7.
- ✓IdentitySignature verified against key ed25519:9f1c…a7
- ✓CustomerActing for Ana Novak, current account ending 4471
- ✓ScopeTravel booking with an Austrian rail operator
- ✓Limits€186 is within €900 per booking; month total €606 of €2,000
- ✓ContextUsual device fingerprint and merchant, normal hours
Allowed. Payment sent under mandate M-0193 and recorded.
Black box
How SIGIL works.
Four steps from a customer connecting an agent to a dispute settled on facts.
Connect
The customer connects an agent in the banking app and signs its mandate with a passkey: what it may do, how much, where and until when.
Verify
Agents sign every request. SIGIL matches agent, customer and mandate, then returns allow, ask or deny with the reason.
Record
Every request and outcome goes into an append-only, hash-chained black box with trusted timestamps.
Resolve
When something goes wrong, SIGIL assembles the mandate, the request, the checks and the outcome. Disputes start from facts.
Customers stay in charge.
In the banking app, customers see every agent they have connected, what each one may do and what it did today. Pausing or revoking takes one tap. The bank gets a sanctioned door for agents instead of shared passwords.
Travel bookings, up to €900 each
€606 of €2,000 used this month
Utilities and rent, to saved payees only
Read-only: statements and receipts
Today
- Trip planner asked to book a €1,240 flight. You were asked to confirm.
- Trip planner booked a train, Vienna to Prague, for €186.
- Bill payer paid the energy supplier €64.90.
Built on open standards.
SIGIL plugs into the rails that card networks and AI platforms are building. It adds what only the bank can provide: the customer's authority, and a record that stands up later.
- HTTP Message SignaturesRFC 9421: how agents sign each request
- OAuth 2.0 Token ExchangeRFC 8693: an agent acting for a customer
- PasskeysWebAuthn: signing mandates and approving exceptions
- Card-network agent tokensWe connect to them rather than compete
- Model Context ProtocolA gateway for agents that use tools
- Policy as codeMandate rules your teams can read and test
Why banks will need it.
Banks are not buying agent controls yet. The rails, the rules and the risks are arriving on a timetable, and the bank that can verify a mandate is the bank that can say yes to agents.
- 2026
Card networks open agentic payments to issuers in Europe, the UK and the UAE. Banks start finding unvetted agents in customer accounts.
- 2027
EU anti-money-laundering rules apply from 10 July, with checks on anyone acting on a customer's behalf.
- 2028
The EU Payment Services Regulation is expected to apply, with new rules on fraud and on how payments are authorised.
- Then
Agents become an ordinary channel. Customers expect to connect them the way they connect a payment app today.
Questions banks ask.
Aren't the card networks solving this?
They secure card payments made by agents. SIGIL covers the bank's side: account access, transfers, mandates across payment rails and the evidence a bank needs for disputes and supervisors. We connect to network agent tokens instead of competing with them.
What happens to agents that don't identify themselves?
They get whatever safe treatment the bank chooses, such as read-only access or a block. The customer is invited to connect the agent properly in the app.
Who is liable when an agent goes wrong?
SIGIL does not change the law. It gives the bank and the customer a shared record of the mandate, the request and the decision, so liability is settled on facts.
When can we use it?
We are building SIGIL with a small group of design-partner banks for 2027. Design partners shape the mandate format and get early access.
Shape SIGIL with us.
We are looking for a few banks and payment firms already working on agentic payments. Design partners get early access and a say in the mandate standard.