A security camera records someone entering an office after business hours. The next morning, a video clip appears to show a different person entering the building. Both recordings look convincing, and ordinary visual inspection reveals no obvious signs of editing. With modern artificial intelligence, replacing faces, removing objects or modifying individual frames has become increasingly accessible. This creates a problem for businesses, investigators and anyone who relies on surveillance footage as evidence.
One response is to authenticate video when it is recorded, rather than attempting to identify manipulation afterward. Cryptographic digital signatures can establish which device produced a recording and whether its protected data has changed. In August 2026, ONVIF introduced a release candidate for its Media Signing Add-on, bringing a standardized approach to this process. The technology does not prevent every form of deception, but it provides a way to examine the integrity of camera footage without depending on visual clues alone.
Digital Signatures and the Integrity of Video Frames
A digital signature is not a visible watermark or a manufacturer’s logo placed over a recording. It is cryptographic information associated with digital content. A compatible verification tool uses this information to determine whether the protected data matches what was originally signed.
The process relies on cryptographic hashes and a pair of related keys. A hash is a mathematical fingerprint calculated from digital data. If the protected data changes, its calculated fingerprint will generally change too. The recording device uses a private key to sign information derived from these hashes. A corresponding public key allows another system to check the signature without revealing the private key.
This distinction matters when examining manipulated footage. Imagine that someone uses generative AI to replace a person’s face in several frames of a warehouse recording. The edited frames may look natural, but their encoded data no longer matches the original signed material. A compatible verifier can identify that the video fails the integrity check.
The same principle applies to unauthorized frame replacement or deletion, although the precise result depends on how the recording is packaged and which signed information remains available. Digital signatures make alterations detectable under the verification system’s rules; they do not physically prevent someone from editing a file.
The ONVIF Media Signing Standard
ONVIF develops interoperability specifications for IP cameras, video management systems and related security equipment. Its Media Signing Add-on is intended to let products from different manufacturers use a common method of video authentication.
The release candidate announced on August 26, 2026, supports encoded H.264 and H.265 video. Compatible cameras and encoders add signing information while producing the video stream. The ONVIF implementation calculates hashes associated with encoded frames and periodically generates cryptographic signatures covering those hashes. Signing information is carried inside the video stream, without visibly changing the picture.
Verification can take place later, after the recording has passed through a network video recorder, storage platform or export process. Software supporting the specification checks the signatures and determines whether the protected recording remains valid. The process also uses device identity information and certificates to establish whether the signing key belongs to a trusted source.
An important feature is the ability to export a selected interval of footage without automatically losing verification. This requires preserving the original signed encoded video data and the metadata needed to validate it. Simply converting a recording into another video format may change that data and prevent the original signature from being verified.
ONVIF published open-source signing and verification code to help manufacturers and software developers implement the technology. As of October 2026, the Media Signing Add-on remains at the Release Candidate stage, with finalization expected before the end of the year. It should not yet be treated as a universally available feature of ONVIF-compatible cameras.
Protecting Surveillance Evidence Against AI Manipulation
The greatest practical value of signed video appears when recordings leave the organization that created them. A security clip might travel from a store’s recording system to an insurance company, an investigator and eventually a legal representative. Each transfer introduces opportunities for accidental modification, missing metadata or deliberate interference.
Consider a collision recorded by a parking garage camera. One party submits footage showing a vehicle entering the scene, while another claims that several seconds were removed before the impact. If the original recording was cryptographically signed, investigators can examine whether the submitted material corresponds to the signed video sequence. They still need to establish whether the selected excerpt provides enough context to understand the incident.
AI-based editing introduces additional concerns. Modern software can generate realistic faces, alter license plates or remove individuals from selected frames. Traditional detection methods may examine unusual lighting, inconsistent movement or image artifacts. Such clues are not always reliable, particularly after compression or deliberate processing intended to hide evidence of manipulation.
Cryptographic verification approaches the problem differently. Instead of guessing whether the scene looks artificial, it checks whether the recording matches data signed by the originating device. This makes it useful alongside forensic analysis, rather than a replacement for it.
Signed recordings can also support chain-of-custody procedures, which document who obtained, stored and handled evidence. A valid signature does not establish who accessed a file or explain every subsequent action. Investigators therefore still need secure storage, access records, documented exports and reliable procedures for preserving original footage.
Technical Limitations and Future Adoption
A valid digital signature does not prove that everything visible in a recording actually happened as it appears. For example, a genuine camera could record an artificial scene displayed on a screen. The resulting footage might be signed correctly even though the underlying event was staged.
Device security creates another limitation. If attackers compromise a camera or obtain its private signing key, they may undermine the reliability of its signatures. Trusted certificates, protected key storage, secure firmware and controlled device access remain essential parts of a dependable system. Similarly, cryptographic verification cannot automatically establish that a camera’s internal clock was accurate.
The current ONVIF add-on also covers video rather than audio. A system that requires authenticated sound recordings needs additional mechanisms, since the video signature alone does not protect the accompanying audio track.
Compatibility deserves attention when planning upgrades. Organizations should verify whether cameras can produce signed streams, whether recording software preserves the required metadata and whether exported clips can be checked independently. Existing support for an ONVIF profile does not automatically establish support for the Media Signing Add-on.
Another development involves the Coalition for Content Provenance and Authenticity (C2PA). ONVIF and C2PA announced a collaboration in June 2025 to promote compatible approaches to digital media provenance. C2PA Content Credentials can document the origin and editing history of media, while ONVIF Media Signing focuses on protecting surveillance video from modification after signing. The approaches are related but not interchangeable.
For businesses replacing security equipment, the immediate priority is understanding which authenticity features are supported and whether they work across the complete recording workflow. A signed stream is of limited use if the recording system discards its verification data during export.
The wider significance of digital signatures is the shift from trusting video because it looks convincing to checking its technical provenance. As synthetic footage becomes harder to distinguish visually, the ability to verify an original recording will become increasingly important. Reliable camera security will still depend on protected devices, properly maintained systems and careful evidence handling, but cryptographic signatures can provide an additional layer of accountability.