Since the advent of artificial intelligence, the increase in fake creations has made it difficult to assess the authenticity of digital evidence in legal proceedings. In addition to the crucial work of the forensic expert, the immutability and traceability features of blockchain technology make it possible to provide security in the chain of custody of digital evidence.

The emergence of artificial intelligence has changed paradigms in several fields, but it has marked a milestone, especially in terms of evidence in judicial processes. We have entered the era of zero trust, that is, absolute and widespread doubt about the authenticity of the digital evidence presented in the proceedings. However, in this scenario, the advances being made in blockchain have emerged as a possible solution.

What is digital evidence?

When we refer to digital evidence, we are talking about information or data that is useful for an investigation that has been stored electronically, whose ultimate purpose is to be a source of evidence in legal proceedings. However, in order for its validity to be undeniable, it is essential to take care of the chain of custody of the information and thus guarantee its integrity and traceability.

In fact, digital evidence is admitted as evidence, as long as it meets three essential criteria:

• Authenticity: it must be proven that the material has not been manipulated or changed, through technical analysis that confirms the fidelity of the file.
• Importance: the content must be relevant to the case, effectively contributing to its clarification.
• Legality: obtaining the material must be legal, respecting fundamental rights such as privacy.

AA's challenges in terms of digital evidence

The introduction of artificial intelligence has complicated the evaluation of digital evidence, especially with the emergence of 'deepfakes', digital manipulations capable of altering images, videos or audio, creating false representations that seem incredibly real. The challenge presented by 'Deepfakes' is significant, as they can distort reality to the point of creating false evidence that seems indistinguishable from real evidence.

The levels to which some 'deepfakes' are reaching to impersonate identities and falsify facts present a real risk of convictions based on altered evidence.

The Role of Blockchain in the Chain of Custody of Digital Evidence

The immutability and traceability features of blockchain technology become important in the field of digital evidence. Specifically, blockchain can facilitate the traceability of evidence, contributing to the security and transparency of the judicial process.

When digital evidence (i.e. video, image or audio) is obtained, one of the first actions usually taken by forensic computer experts or, as the case may be, the Organic Unit of the Judicial Police, is to create a duplicate, which is analyzed by subsequent experts. This copy will have a hass -alphanumeric code-, made by cryptography, which corresponds to the original file, since its content is the same in both files. Any further manipulation of the file will give a different hass. This is one of the mechanisms currently used to prove whether evidence has been tampered with. In addition, blockchain projects are being developed that allow the hash generated to be secured by linking it with a time stamp. Therefore, it is also possible to know when a specific hass has been created.

So does blocking solve all evidence tampering problems? EDJ director Lara Novis says: "it will often remain the key. However, the characteristics of blockchain technology make it possible to at least identify manipulations of digital evidence after the initial collection and registration on the blockchain."

In fact, the use of blockchain in criminal investigations is already being promoted in some countries. The UK Ministry of Justice already recognized the potential of blockchain in 2017 to secure and verify digital evidence, noting that it allows for data summaries and metadata that ensure the authenticity of evidence from its inception.

Conclusion

The intersection of blockchain technology and digital evidence management offers a promising solution to the challenges posed by advances in AA and the emergence of 'deepfakes'. While the role of IT experts in verifying the authenticity of digital evidence is critical, through education, regulation, and the implementation of advanced technologies such as blockchain, it is possible to achieve a higher level of verification of the integrity and authenticity of evidence.

Faced with this challenge, it is essential to educate legal and other professionals, such as members of the Security Forces and Corps who have duties and powers in the field of criminal investigations.

Head of technical architecture at the British Ministry of Justice Elder, Alistair Davidson, stated that Blockchain or distributed ledger technology (DLT) has great potential as a tool for securing and verifying digital evidence in a criminal investigation. He specifically mentioned the use of technology to create records of body camera footage used by officers.

In a blog post published in early November 2017, Davidson detailed how Blockchain could be used in law enforcement, particularly to establish records of footage captured by body cameras used by police officers.

"This trust-distributing property could be truly transformative in situations where public trust in government is not taken for granted."