How Tathastu protects your data

Everything about how we handle encryption, passphrase management, and message delivery.

Passphrase Management

Recovery options

You choose how your passphrase is managed. Both options keep your messages fully encrypted.

User-Managed Passphrase

You keep your passphrase. Document it in your will or a trusted location. When the time comes, your executor provides it to decrypt and deliver your messages.

  • We never have your passphrase
  • True zero-knowledge architecture
  • Works with your existing estate planning
Recommended

Passphrase Escrow

Opt in to have Tathastu securely store an encrypted copy of your passphrase. Good if you want a backup in case your will is lost. When enabled, Tathastu has the technical ability to recover your passphrase under controlled conditions.

  • Passphrase recoverable if will is lost
  • Recovered only by the Tathastu founder, after Life Status Verification
  • Recovery key held in secure offline custody
  • All access attempts are logged and audited

You can switch anytime. Both options keep your messages encrypted with the same AES-256 standard. The difference is who can recover your passphrase: without escrow, nobody can — including Tathastu. With escrow, the Tathastu founder can recover it, but only after Life Status Verification, using a key held in secure offline custody, and solely to deliver your messages.

Technical Details

Under the hood

For those who want to know exactly what's running.

Encryption

AES-GCM-256 authenticated encryption with a random 12-byte IV per message. All encryption and decryption happens client-side in your browser using the Web Crypto API. We store ciphertext. We never see plaintext.

Key Derivation

PBKDF2-SHA256 with 100,000 iterations turns your passphrase into a cryptographic key. Each user gets a unique 16-byte salt. This makes brute-force and rainbow table attacks impractical.

Passphrase Escrow

Optional asymmetric encryption (RSA-OAEP-4096) stores your passphrase under a public key. The matching private key is held by the Tathastu founder in secure offline custody and never lives on any internet-connected system. It is used only after Life Status Verification, solely to deliver your messages.

Access Verification

Nominee access uses time-limited JWT tokens (7-day expiry) and one-time-password verification via email or SMS. Every access attempt is logged in an immutable audit trail that nobody can edit or delete.