VanishShare is built on a fundamental principle: our servers should never possess the mathematical capability to decrypt your data. Here is how we enforce zero-knowledge isolation.
Encryption is executed in the browser sandbox using the hardware-accelerated W3C Web Crypto API. Each secret receives a cryptographically secure 256-bit symmetric key and a unique 96-bit initialization vector (IV) to prevent replay and ciphertext manipulation.
Per RFC 3986 Section 3.5, the URI fragment identifier (the portion following #) is handled exclusively client-side. Web browsers strictly refuse to send hash fragments in HTTP requests. Thus, the decryption key never touches our web servers or proxy access logs.
When an optional passphrase is set, the 256-bit master key is wrapped using PBKDF2 with HMAC-SHA-256 and 100,000 iterations with a unique cryptographic salt. An additional AES-GCM verifier ensures wrong passphrases fail client-side before any request is dispatched.
Step-by-step lifecycle from encryption to permanent destruction:
window.crypto.subtle.generateKey yields an exportable AES-GCM 256-bit symmetric master key (K_master).
Payload text and file bytes are encrypted with K_master and a random 12-byte initialization vector (IV). File metadata (original name, MIME type, size) is encrypted in a parallel ciphertext structure.
Only the encrypted ciphertext and expiration metadata (TTL, max download limits) are transmitted to the server. The raw key is appended to the browser link as #key=... and retained only by the sender.
Recipient navigates to the URL. If email restriction is active, the recipient must confirm a one-time passcode. The browser then extracts K_master from the hash fragment and decrypts the ciphertext locally.
Upon download completion or TTL expiration, the database document and encrypted storage objects are hard-deleted. No snapshots or backups retain expired data.
| Threat Vector | Potential Impact | VanishShare Mitigation |
|---|---|---|
| Compromised Database / Storage | Attacker acquires all stored rows | Attacker only obtains AES-256 ciphertexts. Decryption is mathematically infeasible without client keys. |
| Network Eavesdropping / ISP Inspection | Attacker monitors HTTP / TLS traffic | TLS 1.3 in transit + hash fragment keys are never included in HTTP request lines. |
| Server Rogue Admin / Insider Threat | Admin inspects memory & logs | Plaintext and decryption keys are never transmitted to or processed by the server. |
| Brute-Force Passphrase Attack | Attacker guesses password repeatedly | PBKDF2 with 100,000 iterations slows offline dictionary attacks exponentially. |
Create an encrypted, self-destructing secret in seconds.
Generate Encrypted Secret