What is SHA-256?
SHA-256 is a cryptographic algorithm that transforms any digital file into a unique sequence of 64 hexadecimal characters. Think of it as a mathematical "fingerprint": just as each person has a unique fingerprint, each digital file has a unique SHA-256 hash.
How does it work in practice?
When you certify digital evidence, the SHA-256 algorithm:
- Reads the entire content of the file (image, PDF, video, etc.)
- Applies a series of complex mathematical operations
- Generates a 64-character code that is unique to that exact content
If someone alters a single pixel of an image or a single letter of a document, the resulting hash will be completely different.
Why does this matter for lawyers?
The integrity of digital evidence is fundamental in any proceeding. The SHA-256 hash allows you to:
- Prove that the file has not been altered since certification
- Verify authenticity independently
- Ensure the digital chain of custody
Practical example
Imagine you certified a WhatsApp screenshot. The generated hash was:
a7ffc6f8bf1ed76651c14756a061d662f580ff4de43b49fa82d80a4b80f8434a
If the opposing party claims the screenshot was manipulated, simply recalculate the hash of the original file. If the result is identical, the evidence is intact.
Conclusion
SHA-256 is the technological foundation that ensures the reliability of certified digital evidence. Understanding its basic operation helps lawyers argue more confidently about the validity of digital evidence.