Covert QR Codes: How to Hide in the Crowd

Abstract

This paper investigates a novel approach of distributing a hidden message via public channels. The proposed approach employs visual subterfuge to conceal secret information within a QR code. Using a QR code reader, any individual can decode the public information contained in the QR code. However, only authorized users who have the necessary credentials will be able to obtain the secret message, which is encoded in the form of a secret QR code. We call this a Covert QR (CQR) code scheme. To embed the secret information, this approach exploits the error correction mechanism inherent in the QR code structure. By using QR codes to conceal information, the proposed scheme has the advantage of reducing the likelihood of attracting the attention of potential adversaries. In addition, the information in QR codes can be scanned and decoded through the visual channel. As such, the secret information can be distributed on printed media and is not restricted to an electronic form. Abstract. This paper investigates a novel approach of distributing a hidden message via public channels. The proposed approach employs visual subterfuge to conceal secret information within a QR code. Using a QR code reader, any individual can decode the public information contained in the QR code. However, only authorized users who have the necessary credentials will be able to obtain the secret message, which is encoded in the form of a secret QR code. We call this a Covert QR (CQR) code scheme. To embed the secret information, this approach exploits the error correction mechanism inherent in the QR code structure. By using QR codes to conceal information, the proposed scheme has the advantage of reducing the likelihood of attracting the attention of potential adversaries. In addition, the information in QR codes can be scanned and decoded through the visual channel. As such, the secret information can be distributed on printed media and is not restricted to an electronic form. Disciplines Engineering | Science and Technology Studies

Cooperative Secret Sharing Using QR Codes and Symmetric Keys

“…In previous work, a method of hiding a QR code, which contained concealed information, within a public QR code was examined in Chow et al [14]. This approach was named covert QR codes.…”

“…The covert QR code approach described in Chow et al [14] is a method that can be used to hide the shares. This approach has the advantage that the hidden information itself uses a QR code, which means that both the hidden QR code and the cover QR code have error correction redundancy.…”

“…Unlike our previous work in Chow et al [14], in which the purpose was to use a single non-suspicious QR code to broadcast a secret to a group of authorized participants where each participant can obtain the secret themselves, the protocol proposed in this paper provides a mechanism for a shared secret using QR codes. This means that each participant can only obtain his/her respective share, which does not reveal the secret, and must cooperate with other participants before the secret can be recovered.…”