Hashes detect changes by producing a fixed-size output (the hash value) from an input of any size. When the input data changes, even slightly, the resulting hash value will change significantly due to the properties of hash functions. This is known as the "avalanche effect."
Here’s how it works:
- Input Data: You start with some data (e.g., a file, a string).
- Hash Function: You apply a hash function (like SHA256) to this data, which generates a unique hash value.
- Comparison: If the input data changes (even a single bit), the hash function will produce a completely different hash value.
- Integrity Check: By comparing the original hash value with a newly computed hash value of the modified data, you can easily detect any changes. If the hashes are different, the data has been altered.
This mechanism is widely used in data integrity verification, digital signatures, and cryptographic applications.
