How we guarantee your privacy
Not a promise — a mathematical guarantee. Our architecture makes it technically impossible for us to read your data.
Client-Side AES-256-GCM Encryption
All encryption and decryption happens exclusively in your browser using the Web Crypto API (SubtleCrypto). We use AES-256-GCM — the same algorithm used by the NSA for Top Secret information. A unique 256-bit key is generated per secret using crypto.getRandomValues(), which provides cryptographically strong randomness. The IV (initialization vector) is randomly generated and prepended to the ciphertext.
Zero-Knowledge Architecture
The decryption key is embedded in the URL fragment — the part after the # symbol. Per the HTTP specification, URL fragments are never transmitted to servers. Our infrastructure receives only the encrypted ciphertext. Even if our entire database were seized, every record would be meaningless without keys that were never sent to us.
HMAC Key Commitment
Before storing ciphertext, we compute HMAC-SHA256 over the ciphertext using the encryption key. This HMAC is stored alongside the ciphertext. Before decryption, the client verifies the HMAC. If a server-side attacker replaced the ciphertext with a malicious payload, the HMAC check would fail — protecting against key commitment attacks.
Atomic Burn-and-Return
We use Cloudflare Durable Objects to enforce single-read guarantees. A distributed lock prevents race conditions: if 100 users click the same link simultaneously, exactly one gets the data and the other 99 receive a 410 Gone response. The deletion occurs in the same atomic operation as the read — there is no window between 'read' and 'delete'.
Bot Detection Gateway
Slack, Telegram, Discord, and WhatsApp send crawlers to generate link previews. These bots would burn one-time secrets before humans open them. Our edge gateway detects bots by User-Agent patterns and IP ASN ranges. Bots receive a safe OG preview page — without triggering the burn. Only interactive human browser sessions can reveal secrets.
Compliance frameworks
We process zero personal data inside secrets (zero-knowledge). No personal data means no GDPR Article 32 breach exposure for secret content. Audit logs (Team+) satisfy Article 5(2) accountability requirements.
AES-256-GCM client-side encryption satisfies HIPAA Security Rule §164.312(e)(2)(ii) encryption addressable specification. BAA available on Enterprise plan for covered entities.
Audit logs create immutable records satisfying CC6.1 (access controls) and CC6.7 (encryption in transit). One-click compliance export on Team+ plans.
Zero plaintext storage means cardholder data never transits our infrastructure. AES-256 satisfies Requirement 4 strong cryptography mandate.
Found a security vulnerability?
We take security disclosures seriously. Responsible disclosure is rewarded.
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