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Privacy at Herald

Herald was designed from the ground up to ensure your email address is never exposed to Herald’s servers, notification protocols, or any third party.

Client-side encryption

Your email is encrypted entirely in your browser using TweetNaCl.js (NaCl box encryption). The plaintext email never leaves your device — Herald's servers only ever see the encrypted ciphertext.

On-chain identity

Your encrypted email, nonce, SHA-256 hash, and notification preferences are stored in a Solana Program Derived Address (PDA). Only your wallet can authorize changes to this data.

Decryption in a TEE

When a protocol sends you a notification, Herald decrypts your email inside an AWS Nitro Enclave (Trusted Execution Environment). Memory is zeroed immediately after the email is routed — nothing is persisted.

What Herald never stores

  • ✗Your plaintext email address
  • ✗Your wallet public key (we store SHA-256 hashes only)
  • ✗Any association between your email and wallet in our database

ZK receipts

Every email delivery produces a ZK-compressed receipt on Solana via Light Protocol. This gives you verifiable, immutable proof that notifications were delivered — without exposing your identity.

GDPR compliance

You can delete your on-chain identity at any time from the Preferences page. This permanently closes your IdentityAccount PDA and returns the rent to your wallet. All future notifications will be silently dropped.