The liar's dividend and digital provenance

The "liar's dividend" is a concept formulated by the legal scholars Robert Chesney and Danielle Citron in the California Law Review (2019). The idea: as the public learns that anything can be faked, those caught out can dismiss genuine evidence by declaring it fabricated. The paradox is cruel: the more people are educated about deepfakes, the more the liar's argument is reinforced. The dividend grows, they write, "perversely", in proportion to the success achieved in raising public awareness of fakes. The threat is not only the fake that circulates; it is the generalised suspicion that it licenses.

The driver of the dividend is an asymmetry of cost. Accusing is free, instant and understood by all: "it's a fake" is said in a second. Proving authenticity is slow, costly and hard to read: it takes forensic expertise, tools, technical vocabulary, and the verdict always arrives after the doubt has spread. This asymmetry is not specific to deepfakes: it is a particular case of "Brandolini's law" (Alberto Brandolini, 2013), according to which "The amount of energy needed to refute bullshit is an order of magnitude bigger than that needed to produce it". The cause is also cognitive: a false but simple and appealing claim is adopted effortlessly, where a nuanced truth requires one to pause. Refuting will always cost more than asserting.

Since detecting every fake is a losing race, another path is to certify the real at the source: this is "digital provenance". It attaches to a media file, from the moment of its creation, a cryptographic certificate attesting where it comes from and how it has been modified. The open C2PA standard and its "Content Credentials" layer brought together more than 5,000 members in 2025; Google has watermarked more than 10 billion pieces of content with SynthID; cameras sign the image at the moment of capture (Leica, Sony, Samsung). The aim is not to prove that a file is fake, but to prove that a file is what it claims to be.

Provenance is no silver bullet. Watermarks can be removed or imitated: researchers have shown as much. Above all, a signature attests to an origin, not to a truth: a genuinely captured image can show a deceptive scene. As Sam Gregory, of the NGO WITNESS, sums it up, provenance "provides signals but does not prove truth". And a trap lurks: if we grow used to demanding a certificate, the absence of a certificate will end up passing for proof of a fake, even though the vast majority of genuine content carries none. Finally, the dividend's effect remains debated: it is real but bounded, mediated by partisanship and tempered by verification.