I tried to verify the authenticity of my end-to-end encryption with a friend. However, neither the QR code nor secret codes are visible.
The QR code and the secret codes are a visual representation of the encryption keys used between you and your friend. This set of keys is unique for each friend and it will expire after a certain time period.
As a result, if you have not chatted with a friend for a long time, your encryption keys will not be available. This is done to protect your security and privacy.
Once you send or receive a message with this friend, your QR code and secret codes will reappear.