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Secure Quick Response codes are a secure method for encrypting data into a barcode, which then becomes extremely difficult to decode into the original plain text in the absence of the encryption cipher or key. A typical implementation of SQR codes would be to create a one-time use SQR code on a mobile phone's screen to effectively create a highly secure one-time pad type of encryption of, for example, an online account number.
SQR codes, because they can be used on hundreds of millions of phones without adding more hardware, can operate in a similar way to Near Field Communication handsets for secure mobile payments. A typical implementation is to encrypt and use a precursor physical machine readable token such as the card identity number (CID) written in read-only memory (ROM) of a Secure Digital microSD card contained in a mobile telephone or even the international mobile identity number in the event no microSD card is present, as, for example, on an Apple iPhone. SQR codes may be securely read in a retail environment at the point of sale using 2D barcode scanners or even a low cost web camera. Secure Quick Response codes were first developed by Yodo, a company operating in Japan, and are patent pending.