Quldra QULDRA

Your messages, secured against tomorrow's threats.

Quldra is a messaging app built with post-quantum cryptography from the ground up. Private keys never leave your device. No phone number required. Just secure, private communication designed to stay that way -- even as computing power advances.

Available now on iOS and Android.

What you can do with Quldra

Everything you need for private messaging, built into a clean, focused experience.

Private conversations, your way

Start direct messages or create group rooms. Manage members with roles, promote admins, and keep your conversations organized the way you want.

Share media securely

Send images, GIFs, videos, and files up to 25 MB. All media is encrypted before it leaves your device, so only the intended recipients can view it.

Stay in control of your messages

Reply in threads, edit or delete your own messages, and see when messages are read. Tag conversations as Work, Fun, High Priority, or Personal to keep things clear.

Invite people on your terms

Generate invite links with optional passwords. Set links to single-use. Require admin approval before new members join. You decide who gets access.

Privacy controls that go further

Lock the app with a passcode. Hide message previews from notifications. Keep sensitive conversations in hidden rooms that stay out of sight until you reveal them.

Recover your identity, not your data

Your cryptographic identity is backed by a 12-word recovery seed. If you lose your device, you can restore your identity on a new one without exposing your private keys to anyone.

Built for real-world use

Transparent bandwidth tracking

See exactly how much data you use. Your monthly allowance and any top-ups are tracked separately, so you always know where you stand. No surprise charges.

Native billing on both platforms

Subscribe and manage your plan directly through the App Store or Google Play. No external payment forms. No friction.

Security you can verify

Quldra uses post-quantum cryptographic algorithms to protect your messages today against both current and future threats. Every cryptographic operation happens on your device. Your private keys never touch our servers.

Adversaries collecting encrypted traffic today may attempt to decrypt it when quantum computers mature. This is known as the harvest-now, decrypt-later threat. Quldra is designed to resist it.

ML-KEM-768 ChaCha20-Poly1305 Ed25519 + ML-DSA-65

On-device cryptography

Encryption and decryption happen entirely on your device. Your private keys are stored in platform-secure storage (Keychain on iOS, Keystore on Android) and are never transmitted.

Post-quantum key exchange

Every session uses ML-KEM-768 for key encapsulation, with Ed25519 and ML-DSA-65 hybrid signatures for identity authentication. These algorithms are designed to withstand both classical and quantum attacks.

Continuous hardening

Security is not a feature we ship once. Protocol improvements, key management hardening, and independent review are ongoing priorities on our roadmap.

This statement reflects the current implementation. For technical details, see our published encryption flow documentation.

How your messages stay private

From the moment you type a message to the moment it appears on the other side, your content is protected. Here is how.

Step 1

Your keys are created on your device

When you install Quldra, your device generates a unique cryptographic identity. Private keys are stored in secure hardware-backed storage and never leave your device.

Step 2

Your message is encrypted before sending

Before anything leaves your device, your message is encrypted using post-quantum algorithms. The plaintext never reaches our servers.

Step 3

Encrypted transit through Quldra relay

Our relay infrastructure transports encrypted payloads, delivery receipts, and session metadata. It cannot read your message content.

Step 4

Decrypted only on the recipient's device

The recipient's app uses its own private keys to decrypt the message locally. Only the intended recipient can read what you sent.

Simple, bandwidth-based pricing

You pay for the data you use, not the number of people in your team. A free tier is included with every install.

Starter

1 GB monthly allowance$3/month

For individuals and small groups with everyday messaging needs.

Pay As You Go

+1 GB blocks$5 per GB

Add bandwidth whenever you need it. No plan changes, no commitments. Top up and keep going.

Enterprise

Custom bandwidth + supportContact us

High-volume plans with dedicated onboarding, tailored support, and custom billing arrangements.

Initial pricing. A free tier is included with every install so you can try Quldra before committing to a plan.

Payments

Subscribe through the App Store or Google Play. Enterprise customers can arrange direct billing.

Contact billing