An attestation service is a business that offers a service that confirms that an action was taken by a certain person or group with their involvement. These are mainly used for organizations, events, people and activities. The use cases of an attestation service: Most of the time, they are established to verify specific information like proof of attendance at organizations, events or even people who have participated in activities. But they can also be used for other purposes like verifying performance in government projects or business opportunities.