A concrete example
Changing one letter will overwhelmingly likely change its SHA-256 fingerprint; collisions are possible in principle.
In context
Hashing is not encryption. Encryption conceals a message until it is decrypted; a hash helps check integrity. Matching a fingerprint establishes consistency with particular data, not that the underlying statement is true. Hashing a false invoice does not make it genuine.
The related mechanism, visually
- 01Message + context
- 02Private-key signature
- 03Public-key verification
- 04Authorization, not truth
Read these as connected concepts, not necessarily consecutive steps.
Read the explanation
A private key is used to produce signatures; the corresponding public key lets others verify them. Verification binds a signature to a particular message. The message must also specify its intended context, such as the network and contract: otherwise an authorization may be accepted somewhere it was not intended. Replay protection is an application rule, often involving a nonce; readable formatting alone does not provide it. A wallet can request a transfer, a contract call or a structured message. Read that request, not just the description on the website.
Put the mechanism into context
In this fictional direct transfer, the signed message includes the network, recipient and amount: “send 25 units to Bob”. After signing, someone changes the recipient to Carol but keeps the amount and signature. Compare the original message with the changed message before deciding whether verification can succeed.
Apply it in the workshop →What this mechanism does not guarantee
A recovery phrase can derive many keys. It is not a password that customer support can reset. A hash is not encryption: there is normally no decryption key that recovers the input. For predictable inputs, an attacker can try guesses and compare hashes. Hashing a phone number therefore does not automatically make it anonymous. A verified signature also says nothing about whether the key was stolen or whether its owner understood the request.
Explore the full explanation
Hashes, keys and signatures
A cryptographic hash maps data to a fixed-length fingerprint.