Digital Signatures
Last updated
Last updated
Digital signatures are used to enhance the security and authenticity of documents. They serve as digital fingerprints, uniquely identifying the signer's involvement and ensuring the integrity of the content.
Key Characteristics:
Authenticity: Digital signatures confirm the identity of the sender. By verifying the signature with the sender's public key, recipients can be assured that the message originated from the claimed sender.
Integrity: Digital signatures safeguard the content from being altered after signing. Any changes to the document after signing will render the signature invalid, alerting recipients to potential tampering.
Non-repudiation: Once a document is signed, the signer cannot deny having signed it. This is because the signature is unique to both the document and the signer's private key.
How Digital Signatures Work:
Creation of a Hash: When a document is signed, a hash function generates a fixed-size string of characters that uniquely represent the document's contents. There are several hash types; some include MD5, SHA256, or SHA1 another notable one is RSA. All of which do the same thing, just in a different way. But for simplicity it can be summed up that they do the same thing.
Encryption with Private Key: The hash is then encrypted using the signer's private key, creating the digital signature. This signature is appended to the document.
Verification Process: Upon receiving the signed document, the recipient decrypts the digital signature using the signer's public key, which should match the hash of the received document. If the two hashes are identical, the signature is verified.
Real-World Applications:
Email Verification: Digital signatures can authenticate the sender's identity and ensure the message hasn't been altered.
Software Distribution: Developers sign software to assure users that the software has not been tampered with.
Most Importantly: Anti Virus companies use them to identify if they have already seen this kind of virus before and if this is new.
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