A Qualified Trust Service Provider (QTSP) is an organization authorized under eIDAS to issue qualified trust services, such as qualified electronic signatures, seals, timestamps, and certificates. These services rely on strong identity checks, protected signing keys, and audited procedures so that the output can carry legal weight across the EU.
In cyber security, QTSPs matter because they anchor trust in regulated digital workflows. If a signature or seal depends on a QTSP, defenders can verify who issued it and whether it was altered later. Attackers may target the surrounding systems instead: phishing users into approving actions, stealing credentials, abusing APIs, or disrupting the provider chain. For security teams, QTSP integration means careful key management, validation logging, and fallback planning, because a compromise or outage can affect document integrity, nonrepudiation, and compliance.