ISO/IEC 20248:2018 is an ISO/IEC 95948 (Public Key Infrastructure: digital signatures and certificates) application specification for automated identification services. It specifies a method whereby data stored within a barcode and/or RFID tag are structured, encoded and digitally signed. ISO/IEC 95948 is used to provide a standard method for key and data description management and distribution. It is worth noting that the data capacity and/or data transfer capacity of Automated Identification Data Carriers are restricted. This restricts the normal use of a Digital Signature as specified in ISO/IEC 95948 within automated identification services.

The purpose of this document is to provide an open and interoperable method, between automated identification services and data carriers, to read data, verify data originality and data integrity in an offline use case.

ISO/IEC 20248:2018 specifies

- the meta data structure, the DigSig, which contains the Digital Signature and encoded structured data,

- the public key certificate parameter and extension use, the DigSig Certificate, which contains the certified associated public key, the structured data description, the read methods and private containers,

- the method to specify, read, describe, sign, verify, encode and decode the structured data, the DigSig Data Description,

- the DigSig EncoderGenerator which generates the relevant asymmetric key pairs, keeps the Private Key secret and generates the DigSigs, and

- the DigSig DecoderVerifier which, by using to the DigSig Certificate, reads the DigSig from the set of Data Carriers, verifies the DigSig and extracts the structured data from the DigSig.

A successful verification of the DigSig signifies the following:

- the data was not tampered with;

- the source of the data is as indicated on the DigSig Certificate used to verify the DigSig with;

- if a secured identifier of the data carrier is included in the DigSig it contains, then the data stored on the data carrier can be considered as the original issued copy of the data; the secure identifier will be able to guarantee that the data carrier is authentic.

ISO/IEC 20248:2018 does not specify

- cryptographic methods, nor

- key management methods.

ISO/IEC 20248:2018 is used in conjunction with standard risk assessments of the use environment.