End-to-end encryption

Turn on encryption for a survey in its settings, and responses are encrypted in the respondent's browser with RSA-OAEP + AES-GCM before they're ever sent to our servers — we store only ciphertext.

Because of this, encrypted surveys can't be exported as PDF (we'd need the plaintext to render one); CSV export of encrypted responses still works from within the editor, where decryption happens client-side.