Kudos protects the card numbers in your Kudos Wallet with zero-knowledge encryption. Your card details are encrypted and decrypted only on your own devices, never on our servers.
That means:
Your card numbers are never stored on our systems in a readable form
Encryption and decryption happen only on your device
Kudos does not have the keys to decrypt your card data, so our engineers and administrators can't see your card numbers
Your encryption key is unique to you and works only for your data
How it works
1. A secret key is created on your device. The first time you use Kudos, a unique encryption key is generated directly on your device. It never leaves your device in a form we can read.
2. Your card is encrypted before it's sent. When you add a card to your Kudos Wallet, your card details are encrypted on your device before they reach our servers.
3. We store only the encrypted version. Our servers hold your card data only in encrypted form.
4. Your other devices get access securely. When you log in to Kudos on a new device, it requests your key from one of your existing devices through an encrypted transfer that only your devices can read.
5. Decryption happens only on your device. When Kudos uses your card details, for example to autofill at checkout, they're decrypted on your device. Your unencrypted card numbers are never sent back to our servers.
The technology behind it
Zero-knowledge encryption is the same security model used by leading password managers and end-to-end encrypted messaging apps. Kudos uses:
AES-GCM 256-bit encryption
PBKDF2 with 650,000 iterations to create secure keys
SHA-256 hashing
Public key and private key cryptography, the same technology that secures HTTPS websites
Unique salts for each user
Frequently asked questions
How is this different from regular encryption?
With regular encryption, a company can still decrypt your data on its servers. With zero-knowledge encryption, only your devices can decrypt your card data. Kudos can't.
Will this slow down Kudos?
No. Encryption runs in the background and doesn't affect autofill or checkout speed.
What if I lose access to all my devices?
Kudos has a secure account recovery process that lets you regain access to your encrypted data while keeping the zero-knowledge protections in place. If you need help, contact us at support@joinkudos.com.
Where can I learn more?
Read the full announcement on our blog: Zero-Knowledge Encryption: How Kudos Protects Your Credit Card Data. For how Kudos handles all of your data, see How does Kudos keep my data secure? and our Privacy Policy.