PostGuard is a free platform is for securely sending emails and files. These are two separate services. They both offer confidentiality: protection against reading by the wrong person(s). PostGuard encrypts your emails and files in such a way that only the recipient that you choose can decrypt, and then read them. This works via the free Yivi app for attribute-based authentication: you, as sender choose certain personal attributes of the intended receiver (such as email address, phone number or name). The receiver must then prove, via the Yivi app, to be in possession of these attributes, before the mail/file can be decrypted and read. This is the essence of PostGuard: it reduces confidentiality to authentication. PostGuard is offered for free, as a social service, to make encrypted mail and file sharing easy for everyone. PostGuard is developed with support from NWO and SIDN fonds.

PostGuard is operated by the iHub team at Radboud University (RU) in The Netherlands. As explained in more detail below, iHub/RU is the data controller, in the sense of Europe's General Data Protection Regulation (GDPR): it determines the purposes and means. iHub/RU is also a PostGuard data processor. For PostGuard file sharing iHub/RU is a data processor jointly with the company ProcoliX. Only data that is necessary for the PostGuard service is processed.

Both email and file encryption make use of Identity-Based-Encryption (IBE) via a Key Generation Service (KGS) that is run by iHub/RU. A receiver of an email or file can obtain a decryption key from the KGS after proper authentication (via Yivi). The disclosed attributes are processed very briefly by iHub/RU in order to check if they match the requirements, so that a decryption key can be generated. Immediately after key generation, or after a failed disclosure, the relevant attributes (and associated timestamped IP-addresses) are deleted. iHub/RU does not maintain a log of these data in such disclosures. iHub/RU does count the number of disclosures and the rough location (at country level) of their origin. These data are used only for usage statistics and service improvements.

• When you use PostGuard to send encrypted emails, these emails follow their usual routes via email servers and do not pass through iHub/RU, either as plaintext or encrypted. Hence iHub/RU does not process your emails. If you use the PostGuard browser-based decryption service for decrypting your emails, the actual decryption takes place in your own webbrowser. Hence, also in this case, iHub/RU does not process your emails.
• Transferring files via PostGuard happens via a website hosted by iHub/RU. Via this website iHub/RU processes only the email addresses of the sender and the recipient. These are needed to send notifications about the transfer. The receiver's email address is also used as (standard) attribute to enable encryption and decryption via PostGuard. Sent emails and email addresses are not stored longer than strictly necessary, that is, at most 2 weeks. When you use PostGuard to transfer files, the encrypted files will be stored temporarily at ProcoliX. ProcoliX cannot see the contents of these files because they are encrypted. Each file is accompanied by some basic metadata, like the type of attribute used for encryption and a timestamp. The attribute values are purged. The encrypted files plus these metadata are kept for a maximum of 2 weeks and are then are automatically deleted. Other technical personal data, such as IP addresses, are stored and deleted according to ProcoliX's general policy. When everything is running normally, this data is deleted after two days. ProcoliX temporarily stores the encrypted files but does not have access to the cryptographic keys (private keys) required for decryption. iHub/RU generates the private keys but does not have access to the encrypted files. ProcoliX and iHub/RU do not conspire to jointly decrypt files behind the backs of users.

Technical changes to the PostGuard system, or any new services, may result in modification of this privacy policy. iHub/RU and ProcoliX reserve the right to make such changes and will announce the new privacy policy as soon as possible via this page. For any questions, comments, or complaints about this processing by iHub/RU and/or ProcoliX for PostGuard, please contact the PostGuard team at our contact address. For complaints about the processing of data by iHub/RU or ProcoliX, the Dutch Authority for the Protection of Personal Data (Autoriteit Persoonsgegevens) can also be contacted.