Hide AES-256-encrypted messages inside ordinary JPEGs. 100% client-side, free, open-source. Ghost mode (J-UNIWARD + STC) for stealth, Armor mode's Fortress sub-mode round-trips through WhatsApp. Shadow messages for plausible deniability. Web + iOS + Android.

Hey PH 👋 Christoph here, maker of Phasm. Steganography has been niche academic territory for decades — hiding messages inside images so no one knows they exist — but the tools are all desktop apps last updated before smartphones. We built Phasm because hiding in plain sight should be as simple as sending a photo. Two modes: Ghost uses J-UNIWARD + syndrome-trellis coding from recent steganography research (stealth-first — resists detection). Armor is robust — its Fortress sub-mode is the only stego I know of that survives WhatsApp's standard recompression end-to-end. Everything runs in your browser or on your device — no uploads, no accounts, no servers. The Rust engine (phasmcore) is open-source under GPL-3.0, and we've published https://phasm.app/blog/ walking through the algorithms, math, and trade-offs. Would love feedback — especially from privacy researchers, journalists, and folks who've played with steganography before. Happy to answer questions!

Refreshing to see a security product that clearly states its cryptographic choices instead of hiding behind vague claims.

AES-256-GCM-SIV, Argon2id, open-source Rust core, and fully on-device operation check a lot of boxes for people who actually care about threat models.

The fact that it survives WhatsApp recompression is what really caught my attention. That's solving a practical problem rather than just a theoretical one.

Great work and congrats on the launch.

Refreshing to see a security product that clearly states its cryptographic choices instead of hiding behind vague claims.

AES-256-GCM-SIV, Argon2id, open-source Rust core, and fully on-device operation check a lot of boxes for people who actually care about threat models.

The fact that it survives WhatsApp recompression is what really caught my attention. That's solving a practical problem rather than just a theoretical one.

Great work and congrats on the launch.

Phasm

Hide encrypted messages inside ordinary photos

Hide encrypted messages inside ordinary photos

What's great

What's great