Trust in the correct operation (“bona fide”) of a transaction is sometimes required in order to trust the validity of exchanged data. Authentication of users/subjects does give some trust in the intent of a transaction, but not in its conduct. Malware may cause the other end to send corrupted data or misbehave in other ways. This paper discusses different mechanisms through which nodes can prove to each other that their software stack is clean from unwarranted modifications, called integrity attestation. For IoT applications, integrity assurance can lead to higher trust in the exchanged data, e.g., sensor readings.