GitHub - swisslite/Kryptos: Encrypt right inside any messenger: the keyboard encrypts, the screen decrypts, no jumping between apps. iOS and Android, Signal Protocol, fully offline.
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Encrypt right inside any messenger: the keyboard encrypts, the screen decrypts, no jumping between apps. iOS and Android, Signal Protocol, fully offline. - swisslite/Kryptos

Kryptos is an end-to-end encryption app for iOS and Android that works through any messenger or SMS. You encrypt a message inside Kryptos (or on its keyboard), paste the resulting code into WhatsApp / Telegram / iMessage / Signal / VK / SMS / anything, and your correspondent decrypts it with Kryptos on their side. The messenger only ever carries what looks like random noise — the plaintext never touches it.