A visual data transfer channel is established between a mobile device and a computing entity to facilitate a decoupled cryptographic scheme. The mobile device stores a private key. In operation, a first code is received by the mobile device over the channel. The first code encodes a cryptographic value that secures other information that has been received or generated at the computing entity. The mobile device private key is then applied to the cryptographic value to generate a second cryptographic value, which is encoded to generate a second code. The second code is then rendered on the mobile device display, from which it can then be transmitted back over the visual channel to the computing entity. At the computing entity, the second cryptographic value is recovered from the second code.