How does end-to-end encryption work in ProtonURL?

When you create a ProtonURL, encryption happens entirely in your browser using AES-256-GCM. The server only ever receives and stores encrypted ciphertext. The decryption key never leaves your browser and is never stored on our servers.

What encryption standard does ProtonURL use?

ProtonURL uses AES-256-GCM, a military-grade symmetric encryption algorithm. AES-256 is the same standard used by governments, banks, and security organizations worldwide. GCM mode provides both confidentiality and integrity.

Can I add a password to an encrypted link?

Yes. ProtonURL supports optional passphrase protection. This adds an additional layer of encryption — even if someone guesses the URL, they cannot read the content without the passphrase.

End-to-end encryption · Zero-knowledge

Create an Encrypted Link That Only Your Recipient Can Read

Your content is encrypted in your browser before it ever reaches our servers. Only someone with the link can read it — we cannot.

AES-256-GCM encryption
Zero-knowledge architecture
One-time read
Optional passphrase

Create an encrypted link — free View pricing

How ProtonURL encryption works

Encryption happens entirely in your browser. Our servers never see your plaintext content.

You enter content

Your secret text or file is processed entirely in your browser.

Browser encrypts

AES-256-GCM encrypts your content using a key generated in your browser.

Only ciphertext stored

We store only the encrypted ciphertext. The decryption key stays in your browser.

Recipient decrypts

The recipient opens the link, decrypts in their browser, reads once, and it's gone.

Enterprise-grade encryption standards

AES-256-GCM

The gold standard in symmetric encryption. Used by governments, banks, and military organizations worldwide. ProtonURL uses AES-256 in GCM mode for authenticated encryption.

PBKDF2 Key Derivation

Keys are derived using PBKDF2 with 310,000 iterations per OWASP recommendations, making brute-force attacks computationally infeasible.

Zero-Knowledge

The decryption key is stored only in the URL fragment (#k=...), which is never sent to our servers. We cannot decrypt your content even if we wanted to.

Authenticated Encryption

GCM mode provides both confidentiality and integrity. Any tampering with the ciphertext is detected and prevents decryption.

Secure Random IVs

Every encryption uses a cryptographically random initialization vector (IV), ensuring identical plaintexts produce different ciphertexts.

File Encryption

Files are encrypted using the same AES-256-GCM standard, chunk by chunk, ensuring the same security for large attachments.

Frequently asked questions

Create your first encrypted link

End-to-end encrypted, zero-knowledge, one-time read. Free, no account required.

Create an encrypted link — free