Question 1

Is Wispr truly zero-knowledge?

Accepted Answer

Yes. Your messages and files are encrypted locally in your browser using the Web Crypto API before they are uploaded. The decryption key is placed in the URL fragment (the part after the #), which your browser never sends to our servers. We only store encrypted ciphertext.

Question 2

Can you read my messages?

Accepted Answer

No — and not just as a promise. It is physically and mathematically impossible. Without the key — which only exists in the link you possess — the data on our servers is random noise. We cannot decrypt it even if compelled by law.

Question 3

What encryption does Wispr use?

Accepted Answer

AES-256-GCM for symmetric encryption. The key is generated in your browser using the Web Crypto API (CSPRNG). If you set a password, we use PBKDF2 with 100,000 iterations of SHA-256 to derive a wrapping key, then AES-KW to wrap the master key before uploading.

Question 4

Where is my encryption key?

Accepted Answer

In the link — specifically after the # symbol. Browsers never include the fragment in HTTP requests, so it's never transmitted to our servers, never logged, and never visible in server-side request logs. For password-protected secrets, the key is wrapped by your password and the URL contains no raw key.

Question 5

What happens if I lose the link?

Accepted Answer

The secret is unrecoverable. We don't have the key, so we cannot help you access a lost secret. It will remain encrypted in our database until its expiry time, at which point it is deleted.

Question 6

Can Wispr be subpoenaed for my messages?

Accepted Answer

We can be subpoenaed, but we can only produce what we store: encrypted blobs, IVs, and metadata (creation time, expiry, view count). We don't store decryption keys, plaintext content, sender identities, or recipient identities. A subpoena would yield encrypted data that is useless without the key we don't have.

Question 7

What if someone screenshots my secret?

Accepted Answer

Burn-after-reading prevents anyone from loading the secret a second time — but it cannot prevent the recipient from screenshotting or copying what appears on their screen. Wispr protects the secret in transit and at rest; once revealed and read, the content is in the recipient's hands.

Question 8

Can Wispr employees read my data?

Accepted Answer

No. There is no admin panel that decrypts secrets, no privileged server command that reveals plaintext, and no key escrow. Employees have database access to encrypted blobs only — and those blobs are computationally indistinguishable from random data without the key.

Question 9

Is the source code open?

Accepted Answer

Yes. Wispr is fully open-source. You can inspect every line of cryptographic code, audit the server routes, verify the database schema, or host your own instance. Check the footer for the GitHub link.

Question 10

Has Wispr been independently audited?

Accepted Answer

The cryptographic architecture is designed to be auditable — open source, well-documented, and relying entirely on browser-native Web Crypto primitives rather than custom crypto. We welcome independent reviews. If you're a security researcher, reach out.

Question 11

How does burn-after-reading work?

Accepted Answer

When a burn-after-reading link is opened, our server hard-deletes the encrypted row from the database before returning the payload to the browser. The deletion is not a flag — the row is gone. If someone intercepts and opens the link first, the intended recipient sees a 'Not Found' page, which signals interception.

Question 12

What's the file size limit?

Accepted Answer

10 MB for encrypted files. Encryption happens in your browser, so very large files would be slow to process. The 10 MB limit balances practicality with server costs. If you need to share larger files, consider encrypting them with a tool like GPG and sending the Wispr link for the passphrase.

Question 13

Can I send the same message to multiple people?

Accepted Answer

With burn-after-reading enabled, no — it's strictly one view. To send to multiple people, disable burn-after-reading and set a Max Views count equal to the number of recipients. Or generate a separate secret per person, which gives each recipient a unique, individually burnable link.

Question 14

What's the difference between expiry and max views?

Accepted Answer

Expiry is time-based: the secret self-destructs after the time limit regardless of how many times it was viewed. Max views is access-based: the secret self-destructs after N opens regardless of time. A secret is deleted whichever condition triggers first.

Question 15

Does the password go to the server?

Accepted Answer

Never. The password is used entirely within your browser to derive a key via PBKDF2. That derived key wraps (encrypts) the AES master key. The server receives the wrapped key — which is useless without the password — and never sees or stores the password itself.

Question 16

Can I edit a secret after creating it?

Accepted Answer

No. Secrets are immutable once created. The ciphertext is encrypted before upload, and we have no mechanism to modify or re-encrypt it. If you need to change the content, create a new secret and share the updated link.

Question 17

What happens when a secret expires?

Accepted Answer

Expired secrets are deleted lazily — on the next access attempt. When someone opens an expired link, the server checks the expiry timestamp, deletes the row, and returns a 'Not Found' response. There is no background sweep running on a schedule.

Question 18

Can I use Wispr on mobile?

Accepted Answer

Yes. Wispr is a progressive web app that works in any modern mobile browser — Safari on iOS, Chrome on Android, Firefox Mobile. The Web Crypto API is available on all modern mobile browsers. Everything works the same as on desktop.

Question 19

How do I know if my secret was viewed?

Accepted Answer

Currently, Wispr does not send read receipts or notifications when a secret is opened. If burn-after-reading is enabled, you can tell it was viewed if the link no longer works. Notifications and delivery receipts are on our roadmap.

Question 20

Can I use a custom link ID?

Accepted Answer

Yes. When creating a secret, you can set a Custom Link ID (letters, numbers, and hyphens, 3–32 characters). Your secret will be accessible at /s/your-id. If the ID is already taken, you'll see an error and can choose a different one.

Question 21

What QR code options are available?

Accepted Answer

After creating a secret (without password protection), a QR code is generated automatically. You can scan it directly or share it. QR codes encode the full URL including the encryption key fragment, so the recipient scans once and the secret is revealed immediately.

Question 22

Do you log IPs?

Accepted Answer

We maintain standard ephemeral server logs for abuse prevention (DDoS mitigation). These may contain IP addresses but are automatically purged within 30 days. We do not correlate IPs to specific secrets at the application level.

Question 23

Is my IP address logged when I reveal a secret?

Accepted Answer

Your IP may appear in system-level access logs (standard web server behavior), but it is not stored in our application database and is not correlated to the specific secret you revealed. System logs are purged within 30 days.

Question 24

Do you use analytics or cookies?

Accepted Answer

Zero tracking scripts, zero cookies. We use browser localStorage solely to remember UI preferences (e.g., dark mode). There are no analytics, no A/B testing frameworks, no ad networks, and no third-party scripts of any kind.

Question 25

Is Wispr GDPR compliant?

Accepted Answer

Yes. Because we store no plaintext personal data and our design is inherently data-minimizing, we're compliant by default. We don't process personal data in any meaningful sense — we store encrypted blobs that we cannot read.

Question 26

Do you sell or share my data with third parties?

Accepted Answer

No. We have no data to sell — the only things we store are encrypted blobs we cannot read, plus minimal metadata (expiry, view count). We have no advertising relationships, data broker relationships, or data-sharing agreements.

Question 27

What do you do with government requests?

Accepted Answer

We comply with valid legal requests but can only produce what we store: encrypted ciphertext and metadata. We cannot produce keys or plaintext because we don't have them. We publish a warrant canary at /canary that goes dark if we receive a secret order we cannot disclose.

Question 28

Is Wispr available in all countries?

Accepted Answer

Wispr is accessible globally. We don't geo-block any countries or IP ranges, including those using Tor or VPNs. Some restrictive jurisdictions may block access — if you're affected, using Tor or a VPN typically resolves this.

Question 29

What browsers are supported?

Accepted Answer

Any modern browser that supports the Web Crypto API: Chrome 37+, Firefox 34+, Safari 11+, Edge 79+, and their mobile equivalents. If your browser is from the last five years, it works.

Question 30

What happens to my data if Wispr shuts down?

Accepted Answer

All stored secrets are encrypted data we cannot read. On shutdown, all database records would be permanently deleted. Because we have no keys, wiping the database is complete erasure. The open-source code means anyone can self-host their own instance.

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