The hash value is a digital fingerprint of the memory card data. This verifies the integrity of the data. This value changes when the data changes, which indicates tampering. It is used for forensic investigation and authenticity of evidence.
Tech News: In many cases we have heard the term ‘Hash Value’ in relation to memory cards. The hash value is the digital fingerprint of the data present in the memory card. Therefore, if there is even the slightest change in the data on the memory card, the hash value changes completely. Let us know in detail what is hash value.
To put it in simple words…
- A file/data → using a hash algorithm (MD5, SHA-1, SHA-256) → a code is created
- the same code is the hash value
- Later, when the same data is examined again, if the hash value remains the same, it is confirmed that there has been no change in the data.
Reasons for using hash value in memory card
1. To check that the data has not been corrupted (e.g. no error occurred while copying the card).
2. To find out whether there has been any tampering with the data – such as in CCTV, dashcam, body cam and forensic investigation.
3. To be accepted as evidence in courts. If the hash values match, it proves that the data is genuine.
4. In secure devices – like ATMs, POS machines and smart cards.
Example
Hash value of file in memory card: ABC123
Hash value after copying to computer: ABC123
✔️ No change in data
• If the hash value changes
❌ So the data is corrupt or changed.
Commonly Used Hash Algorithms
MD5 – fast, but less security
SHA-1 – old
SHA-256 – Strong and most commonly used today.
In short, the hash value is a security code that is used to ensure that the data in the memory card has not been changed.