What is TSP (Trust Service Provider)?
An EU-recognized organization that issues digital certificates and timestamp tokens used in Advanced and Qualified eSignatures.
Under eIDAS, a Trust Service Provider (TSP) is an organization that creates and maintains the cryptographic trust infrastructure for electronic signatures: issuing signing certificates, providing timestamp tokens, and operating the technical systems behind AdES and QES. A Qualified TSP (QTSP) meets additional requirements and is listed on the EU Trusted List — only QTSPs can issue Qualified Certificates that back Qualified Electronic Signatures (QES).
What a TSP does
TSPs verify the signer's identity (typically via video-ID or in-person), issue an X.509 certificate that binds the signer to a key pair, store the private key in a secure HSM (or on a smart card the signer holds), and operate a timestamping service that anchors each signature to a verifiable time. The signed document carries the TSP's embedded certificate so any verifier can confirm authenticity.
TSP vs CA
A Certificate Authority (CA) is a TSP that specifically issues certificates. TSPs cover the broader set: timestamping, long-term validation (LTV), eSignature creation services. All CAs are TSPs but not all TSPs are CAs.
Choosing a TSP
PDF Verified integrates with an EU QTSP for AdES/QES signing on Business Plus and Enterprise. The TSP appears on the audit certificate as the issuing authority for the signer's certificate.