Exchange Encrypted Messages Offline
To use, first click the `Generate New Keypair` button and save or print out (preferred) both QR Codes. Exchange a copy of your "public key" QR Code with a recipient's "public key" QR code.
When you want to send a message, click `Encrypt Message` and follow the prompts provided. Be sure to have your "private key" and the recipient's code on hand when you do. Once you have made an encrypted message, give it to the recipient.
If you have recieved a message, click `Decrypt Message` and follow the prompts provided. Be sure to have your "private key" and the sender's code on hand when you do. Once the message is decrypted, you will be able to view the message until you refresh or leave this page.
As you enter in your keys and messages, you'll notice that hash values (aka checksums) are generated. Hashes are unique, irreversible strings of characters. During the encryption or decryption process, keep note of these so that you and your sender/recipient can verify the integrity of your messages.
This application works offline as well. If you do not want to rely on an internet connection, you can download this webpage - just make sure you download it as a complete webpage (there may be a `Save As` option that says "Webpage, complete").
QR Code Crypto uses the X25519 algorithm, which is only supported by certain browsers (ex. Firefox) at this time. Also, the Barcode Detection API is not supported enough to be implemented in this project yet. Until then, you will have to extract the text from your QR Codes with your mobile device and copy them into the input fields.
If you would like to learn more about how public and private keys work, check out the articles below.
Enjoy! :)
2.0.1 Beta (2/18/25): Updated content and styling.
2.0.0 Beta (2/15/25): Changed the text input interface from JavaScript alerts to HTML and added digest generation for each input field, fixed date comparison for keypair expiration check, and fixed bug with QR Code not displaying after encrypting message.
1.4.0 Beta (2/11/25): Added content + a keypair expiration check.
1.3.0 Beta (2/6/25): Increased the maximum character length allowed for messages by circumventing redundant data from being included in the ciphertext.
1.2.0 Beta (2/4/25): Added error handling for user input + set maximum character length for message.
1.1.1 Beta (2/1/25): Improved and added content to webpage.
1.1.0 Beta (1/25/25): UI fixes + added checksum generation for keypairs and messages.
1.0.0 Beta (1/25/25): The first publication of this tool!