Transaction device security

A method of a manufacturing a transaction device, the method comprising:

• storing account information and a reference code associated with a user account in a chip (308);
• positioning the chip (308) on a chip enclosure;
• embedding the chip (308) in the chip enclosure;
• applying the reference code to a reference code portion of the chip enclosure in a readable format, the reference code portion being separate from the chip,
• wherein the chip (308) is configured to generate a cryptographically signed version of the reference code stored in the chip (308) upon receipt of a request message by encrypting the reference code with a public key of a third party service provider and then digitally signing the reference code using a private key, such that the reference code is retrieved from the cryptographically signed version of the reference code of the chip (308) using the public key of the third party service provider and is sent to the third party service provider to decrypt the retrieved reference code with the private key of the third party service provider for comparison with the readable reference code of the reference code portion (326).