Authenticity and responsiveness of evidence (e.g., biometric evidence) may be validated without regard for whether there is direct control over a sensor that acquired the evidence. In some implementations, only a data block containing evidence that is (1) appended with a server-generated challenge (e.g., a nonce) and (2) signed or encrypted by the sensor may validate that the evidence is responsive to a current request and belongs to a current session. In some implementations, trust may be established and/or enhanced due to one or more security features (e.g., anti-spoofing, anti-tampering, and/or other security features) being collocated with the sensor at the actual sampling site.