On everything you sign, carry and show.
A letter, a label, a badge, a card, a tag. Your mark is a small wavy line with a sixteen-character code under it. The same mark goes on each of these. Anyone can see it, and seeing it gives them nothing. Only a device on your own list can sign with it or answer for it. Someone points a phone's camera at it and asks. You decide what they get.
We are already building most of these, and we have confirmed that every one is technically feasible under our patent-pending design.
Each scene carries one of three labels. Live means it works in SigWave today: at sigwave.id for anyone, and in the SigWave app, which is in testing with a small group. Built in Synap means it works today in Synap, Synaping's personal knowledge system, a separate product from the same company. In development means we are working on it now.
Checking works for anyone at sigwave.id/scan. Answering and signing happen in the SigWave app, which is in testing.
Every photograph on this page is a staged sample: a real mark and real app screens placed into a made-up scene. The people in them are not real.
Know who it is before you open the door.
A ride, a stranger, a knock, a school gate, a call. Each of these works today.
A ride, checked from the back seat
The card on the seat back is signed with the driver's mark. Before the trip starts, you point your phone's camera at it at sigwave.id/scan. It shows the mark the card was signed with and answers Signed, or Changed if a line was altered.
You can also ask the driver a question. Only the driver's own phone can answer it.
Meeting someone new
You meet someone for the first time and would rather not give out your number. You lay your phone on the table showing your mark, and they scan it. From then on they can ask your mark a question, and each time you decide what to send.
A courier at the door
Someone knocks and says they have a delivery. With the chain still on, you scan the mark on their badge and ask a question. Only a phone on that mark's own list can answer, so a copied badge stays silent.
School pickup
An adult at the gate says they are here for a child. The teacher scans the mark on their badge and asks before the child leaves with them. Only the phone that belongs to that mark can answer, and the teacher can compare the mark with the one the family gave the school.
A call you did not expect
A stranger calls, then sends your mark an ask. Your phone shows only what they call themselves, Calls itself Grace Whitfield, and never says that they are. You see their own words and the exact question, and you can decline and send nothing.
A phone call that shows the caller's mark before you pick up is in development.
Sign it once. Anyone can check it.
A letter, a label, a mug, a receipt, a card. Each of these works today.
A letter anyone can check
In our test builds of the iPhone app, you sign a letter with Face ID. The printed page carries your mark and a document code. Anyone can point a phone's camera at the page at sigwave.id/scan, no app needed, and it answers Signed, or Changed if a line differs from what you signed, or Not signed. Robb Dixon did this on September 25, 2026. It is a real letter, not a sample.
A label at the pharmacy
You are the pharmacist. You sign each bottle's label on your phone with Face ID and choose to let anyone holding it check it. A customer at home points a phone's camera at the label at sigwave.id/scan. It shows the mark the label was signed with and holds the label's lines against what you signed: Signed, or Changed if a word differs. You do not answer for each bottle. The label in the picture is a sample from a made-up pharmacist.
A maker's hang tag
You are the potter. You sign the tag for each mug on your phone with Face ID and tie it to the mug. Whoever holds the mug can point a phone's camera at the tag at sigwave.id/scan and see Signed, and the mark it was signed with, because you chose to publish it. They do not sign up for anything, and the picture never leaves their phone; only the code printed on the tag is looked up.
A receipt from a market stall
You sell at the farmers market. You sign your receipts on your phone with Face ID, the same way the potter signs a tag. A customer points a phone's camera at a receipt at sigwave.id/scan and sees Signed, and the mark it was signed with. They do not sign up for anything.
A business card that is an address
Your card carries your mark, and that is all. It does not list your name, your phone number, or where you live. Whoever holds the card can scan it at sigwave.id/scan and ask for your name. Each time, you decide whether to send it.
Show what they need, and nothing more.
The gym, the field trip and the first shift work today. The door, the ticket, the payment and the shop window are in development.
A gym card
Your member card carries your mark. At the front desk they hold a phone over it and ask one thing: over 18? You answer yes with Face ID and sign the gym's form on your phone with the same mark. No license photocopied, and no birth date in the gym's files.
A field-trip badge
You are the chaperone. The badge on your lanyard carries your mark and no name. At the museum door, staff hold a phone over it and ask two things: over 18, and holds a valid photo ID. Your phone shows who is asking. You answer yes to both with Face ID. Both answers are your own word; no office has checked them. Your license stays in your pocket.
A caregiver, before the first shift
You are the caregiver, and a family is about to leave their child with you for the first time. They hold a phone over your mark and ask three things: over 18, holds a photo ID, and your first-aid (CPR) training is up to date. You see who is asking and the three questions, and answer yes to all three with Face ID. Each answer is your own word, and only a device on your own list can give it. Next, the place that taught you CPR can stand behind that answer. The place for such a school to join is built on our service, and none has joined yet.
A badge that opens a door
Your office badge carries your mark instead of a number a reader can copy. At the door, the reader asks your mark and your phone answers. A lost badge, or a copy of one, opens nothing on its own.
A ticket that only works for you
Your ticket carries your mark. At the gate, the scanner asks the mark, and only your phone can answer. A screenshot or a copy gets no one in.
A payment that works once
At the counter you scan the shop's mark and pay with your own mark instead of a card number. The permission says this shop, this amount, this once. A copy of it buys nothing anywhere else, so thieves who broke into the shop's computers would find nothing they could spend.
Reach a shop by its mark
A shop puts its mark in the window instead of a phone number. You scan it and send the shop a question, and the answer comes back signed with the shop's mark. Today every mark belongs to a person. Marks for businesses are what we are building now.
It asks you first.
A service asks before it acts in your name. Next, an assistant carries a mark of its own and asks you the same way.
Was this you?
A service you use sees something start in your name, such as a new computer being added to your account. Before it goes ahead, it asks you. It shows a short code on its own screen and sends your phone the same question in its own words. You check that the codes match and tap Confirm, or tap Not me. The question runs out within five minutes.
Synap is the first service to ask this way: it asks before a new device can approve anything on an account. Our founder has used it once, on a test build.
An assistant with its own mark
An AI assistant works for you inside the systems people already use: a phone line, a counter, a locker, a form, a clinic's front desk. It carries its own mark and acts only within limits you signed. For anything that matters, it asks you first, and you confirm on your phone or your wrist.
Asking first already runs in Synap: what an agent drafts waits until its person approves it from a linked phone, and linking that phone goes through a SigWave confirm, used so far once, by our founder, on a test build. Marks for agents are what we are building now.
Ask your prescription a question
The label on your prescription bottle carries the mark of the doctor's office that prescribed it. Scan the mark with your phone and ask about this prescription: is this what my doctor prescribed, can I take it with food. The answer comes from the prescribing doctor's own AI agent, signed with the doctor's office mark, so you know it is theirs. Anything urgent is routed to the doctor. It answers questions about this prescription and passes the rest on. It does not diagnose.
One piece already runs in Synap, Synaping's personal knowledge system: an AI agent that drafts, and waits for its person to approve before anything goes out. Marks for doctors' offices and their agents, and checking an office's mark against its own public records, are what we are building now. No SigWave mark takes part in this today.
The same mark, everywhere else.
We are working on these now. Where part of one already runs in Synap, the card says so. Each one uses the same mark you can make today, answering only when you say so.
A photo that carries its maker's mark
A photo or a recording carries the mark of the person who made it. Anyone can check whose mark it carries and whether it was changed since. A copy with the mark stripped off cannot be checked at all. Synap already puts a public time stamp on documents that anyone can check without relying on us; photos and recordings are not covered yet.
One person, one vote
You show you are allowed to vote, or to get help you are owed, and no office has to build a file on you to check. The office learns that you may. It does not learn anything else about you. The yes-or-no ask it needs is live in SigWave today; an office that can stand behind the answer has not joined yet.
A new doctor, only the part she needs
You see a new doctor. She gets the part of your medical record the visit needs, for as long as the care lasts. When care ends, the permission ends with it, instead of staying in a file for good.
The share-and-withdraw part runs today in Synap. No medical record or care provider product has been built on it yet.
Your work, on loan to your employer
What you learn and make at a job stays yours. You lend it to the company while you work there, and take it back when you leave. Today you hand it over on the first day.
The lending part runs today in Synap: you share chosen entries with another party and withdraw them, after which their searches find nothing and a receipt records it. It cannot erase a copy someone already saved elsewhere. SigWave marks join it next.
A bank's mark, checked against the bank
Today every mark belongs to a person, and a phone that reads one says only what the mark calls itself. Next, a bank gets a mark of its own, and your phone checks it against the bank's own website and the government's public list of banks. A scam that calls itself a bank would fail that check.