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Kryptos vs Salty: catalog facts
Kryptos	Salty
Best for: Adding encryption to conversations in messengers you do not trust	Best for: Sending occasional secrets over an untrusted messaging channel
Free Free and open source under the AGPL-3.0 licence.	Free Free and open source under the MIT licence.
Android, iOS	Android
Adds end-to-end encryption on top of any messaging app or SMS Uses the Signal Protocol with keys stored on the device All 4 strengths for Kryptos Adds end-to-end encryption on top of any messaging app or SMS Uses the Signal Protocol with keys stored on the device No accounts or servers; works offline Works between iPhone and Android	AES-256-GCM encryption with PBKDF2 key derivation Works offline and keeps history on the device All 3 strengths for Salty AES-256-GCM encryption with PBKDF2 key derivation Works offline and keeps history on the device Works alongside any messaging app
Not in the App Store; iOS install requires sideloading or signing Both people need Kryptos to read the messages All 3 limitations for Kryptos Not in the App Store; iOS install requires sideloading or signing Both people need Kryptos to read the messages Messenger still sees who you talk to and when	Both sides must exchange the shared key securely beforehand Android only All 3 limitations for Salty Both sides must exchange the shared key securely beforehand Android only Small project without an independent security audit mentioned
Downloadable app	Downloadable app
Open source	Open source
License: AGPL-3.0-only	License: MIT
No account needed	No account needed
Offline features available	Offline features available
Official website Full listing and sources Sources for Kryptos datakeeper.pages.dev/kryptos github.com/swisslite/Kryptos Catalog checked October 2, 2026	Official website Full listing and sources Sources for Salty github.com/vauth/salty-app f-droid.org/packages/com.vauth.salty Catalog checked October 2, 2026

“Not stated” means we have not confirmed it. Features can vary by device and plan.