What is it? Peppol CIP?
Short answer
Peppol CIU (P)ublic Key Infrastructure) is a digital certificate system that ensures that in the network Peppol only trustworthy, certified participants communicated, namely Access Points. It protects the transfer between Access Points (party identity, integrity and encryption), but does not verify the content of invoices or their accounting accuracy.
Not among people
The CIU shall verify the identity of Access Points, not natural persons.
Encryption and integrity
CIP protects communication channel, not content XML.
Different from the eIDAS signature
The electronic signature of the document is a separate mechanism.
Infrastructure layer
CIP works at Access Points level, not billing software.
Conclusion
Peppol the CIU protects the transfer between Access Points identity and encryption; it is not directly related to the content of the invoice or its possible electronic signature under the eIDAS.
Not legal advice. Machine-translated answer, not yet manually reviewed. For the exact wording, see the Slovak original.