DEEP DIVE

Your Keys, Your Choice: Introducing Selectable Encryption on Sryptos

Sryptos Engineering
Sryptos Engineering
November 5, 2025

At Sryptos, our foundational promise is to give you absolute control over your privacy. Today, we're taking that promise a step further by introducing Selectable Encryption. You can now choose the perfect balance of security and convenience for each of your conversations. This is a powerful new feature, and this post will break down what it means, how it works, and how to choose the right mode for you.

Abstract visualization of digital encryption

The Two Choices: E2EE vs. Synced AES

Until now, all Sryptos chats used our highest security mode: End-to-End Encryption (E2EE). We've now added a second option, Synced AES-256, which offers robust encryption with the convenience of multi-device chat history. Let's compare them.

End-to-End Encryption (E2EE)

The digital vault. Maximum security, single-device focus.

Maximum possible security; keys never leave your device.
No one, not even Sryptos, can ever access your message content.
Complete control over your data's lifecycle.
Chat history does not sync across multiple devices.
Losing access to your device can mean losing your chat history permanently.
Requires re-establishing trust when logging in on a new device.

Synced AES-256

The secure sync. Strong encryption that follows you.

Seamlessly syncs chat history across all your logged-in devices.
Conveniently restore your chats when you log in on a new device.
Maintains strong AES-256-GCM encryption at all times.
Slightly lower theoretical security compared to pure E2EE.
Relies on a master key for decryption which must be securely managed.
Sryptos can technically access the encrypted data blobs (though not the keys to decrypt them).

How It Works: A Look Under the Hood

Both methods use industry-standard, battle-tested cryptography (AES-GCM), but they differ in how the encryption keys are managed. Our commitment to open standards is a core part of our philosophy at BHK Vision Labs.

End-to-End Encryption (E2EE)

This is the gold standard for private communication. Your device generates a unique private/public key pair for each conversation. The private key never leaves your device. Your public key is shared with your contact via our Firestore backend, and you receive theirs. A shared secret key is then derived using Elliptic-curve Diffie-Hellman (ECDH). This shared key is what encrypts and decrypts your messages. Because only the two participating devices have the keys, no one in the middle—not even Sryptos servers—can read the content.

Synced AES-256 (AES-GCM)

This mode is designed for convenience without sacrificing strong encryption. Instead of a key pair per chat, this mode uses a single, powerful master key derived from your account credentials. When you send a message, it's encrypted on your device using this key with AES-256-GCM. The encrypted message is sent to our server and then to your recipient. If you log in on another device, that device also gets access to your master key, allowing it to decrypt your entire chat history. While Sryptos servers temporarily handle the encrypted "blobs" of data, we never have access to the master key needed to decrypt them.

Which Mode Should You Choose?

Choose E2EE if...Choose Synced AES if...
You prioritize maximum possible security above all else.You frequently switch between a phone and a computer and need your chats to be there.
Your conversations are highly sensitive (e.g., journalism, activism).Convenience and ease-of-use are your primary concerns.
You primarily use one device for Sryptos.You are comfortable with a security model similar to other major messengers, but with stronger privacy guarantees.

How to Change Your Settings

You can set your default preference for all new chats by going to Settings > Encryption. When you create a new chat, it will automatically use your chosen default. You can also override this setting for any individual chat in that chat's info panel. Remember, changing the mode only affects new messages; old messages remain encrypted with the previous method. The user-centric design of our tools is a hallmark of BHK Vision Labs.

Our Commitment to Your Privacy

By offering this choice, we are reaffirming our core belief: you should be in control. Whether you need the impenetrable fortress of E2EE or the secure convenience of Synced AES, Sryptos provides the tools to communicate freely and privately, on your terms. We will continue to build features that empower you, not us.