The hash value of Bitcoin is a mathematical process that converts data into a unique fixed-length string. For example, the phrase "Hello, World!" is passed through a hash function and converted into a unique value like "2ef7bde608ce5404e97d5f042f95f89f1c232871."
This hash value has no direct relation to the original data but serves as a "fingerprint" to identify it. In the Bitcoin blockchain, each block includes the hash value of the previous block, so if one block is altered, all subsequent block hashes change as well.
This makes data tampering extremely difficult. Hash values create significant differences even with small changes, ensuring the integrity of transactions. Through this process, the blockchain prevents tampering and maintains security.