How Digital Signatures are Verified
The verification process involves several steps:
Signature Creation: When a signer signs a document, a cryptographic hash (a unique digital fingerprint) of the document is created using a hashing algorithm. This hash is then encrypted with the signer’s private key to create the digital signature.
Signature Transmission: The signed document, along with the digital signature, is sent to the recipient.
Signature Verification: Upon receiving the document, the recipient’s software uses the signer’s public key to decrypt the digital signature, retrieving the original hash value.
Hash Comparison: The recipient’s software generates a new hash value from the received document using the same hashing algorithm. It then compares this new hash value with the decrypted hash value from the digital signature.
Verification Result: If the hash values match, the digital signature is verified as authentic, and the document’s integrity is confirmed. If they do not match, the signature is invalid, indicating that the document has been altered or the signature is not genuine.