واژهنامه
Digital Signature
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A digital signature is a cryptographic mechanism that proves a piece of data (such as a transaction) was authorized by a specific party and has not been altered. It is the blockchain equivalent of a handwritten signature — but mathematically unforgeable.
How it works
- The sender creates a hash of the transaction data
- The hash is encrypted with the sender's private key — this is the signature
- The signature is attached to the transaction and broadcast
- Anyone can verify the signature using the sender's public key, confirming:
- The transaction was signed by the private key owner
- The data has not been modified since signing
Transaction data → Hash → [Sign with private key] → Digital signature
Signature + data → [Verify with public key] → Valid / Invalid
Why it matters in blockchain
Every transaction on Bitcoin, Ethereum, and virtually all blockchains is protected by a digital signature. Without a valid signature:
- The network rejects the transaction
- No one can spend funds from an address they don't control
This is what makes "not your keys, not your coins" true — only the private key holder can produce a valid signature for that address.
