Question

What is the relationship between asymmetric encryption and digital certificates? Discuss the implications.

Answer 1

Asymmetric cryptography, which is often known as public key cryptography, it uses both public keys and private keys for encrypting and decrypting the data. The keys are very large numbers that are paired and aren't identical. One key is shared with everyone(public) and the other is kept hidden(private). Any one key will be used to encrypt the data and on the other side the other key will be used to decrypt the data providing security to the encrypted data. Many protocols like SSL, OpenPGP, etc. use this method to encrypt and decrypt the data and for digital signatures.

For asymmetric encryption to provide confidentiality, integrity, authenticity and non-repudiation, users and systems must be sure that the public key is authentic, and that it belongs to the person or entity claimed and it has not been falsified or replaced by a public key by a malicious third person. A very common approach is  public key infrastructure (PKI) where the trusted certificate authorities certify ownership of key pairs and certificates.

The benefits of asymmetric cryptography are:

• The distribution of keys problem is eliminated by this as there's no need of exchange of keys.
• Security is increased as the private keys aren't exchanged  
• The use of digital certificates helps receiver verify that the message has come from a valid sender.

There are some disadvantages too:

• It is slow compared to the symmetric cryptography.
• If anyone loses the private key, he can't decrypt the message anymore.
• If a hacker gets the private key, then he can decrypt all the messages.