Digital signature ensures the authenticity and integrity of information. Digital certificates guarantee the non-repudiation of information.
The sender hashes the electronic document to get a digest, then encrypts the digest with a private key to get a digital signature. The digital signature and the electronic document are sent to the receiver. After receiving the digital signature, the receiver performs Hash calculation on the electronic document to obtain the digest. Then, the digital signature is decrypted with the public key and compared with the digest.
Digital signature can guarantee the authenticity and integrity of documents. It’s real and it hasn’t been tampered with.
The justification for authenticity lies in the fact that the receiver can decrypt it with a public key. Because it’s asymmetric encryption, private key encryption, public key decryption;
The reason of integrity is that the decrypted summary is consistent with the calculated one.
The digital certificate is an auxiliary means of digital signature to ensure the validity of the public key used to decrypt the digital signature and ensure that it is not switched. Because hackers may secretly replace the recipient’s public key, and then send the documents processed with their private key to the recipient, they can also get the verification result.
How to ensure that the public key is your public key?
The certificate center (CA) uses its own private key to encrypt the sender’s public key and some related information to generate a “digital certificate”. The receiver uses the CA’s public key to unlock the digital certificate and retrieve the real public key. Digital certificates can be done by everyone. Only digital certificates produced by authoritative CA can be meaningful.
The connotation of electronic signature and digital signature is not the same, digital signature is one of the electronic signature technology, but the relationship between the two is also very close, the signature mentioned in the current electronic signature method, generally refers to the digital signature.
Reference Article: What is a digital signature?
What is the function of digital signature?
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