Digital Signatures and Digital Certificates

This video explains the purpose of digital signatures and how they work. It begins by reviewing encryption and decryption using an asymmetric pair of keys, and then explains the significance of this when it comes to digital signatures, namely that it doesn’t matter which of the key pair is made public and which is kept private. The video then illustrates the digital signing process. Specifically, the creation of a hash value for the document (also known as a digest) using a hash algorithm such as SHA256 (which was created by the National Security Agency). It shows how document digest is then encrypted using the sender’s private key before being attached to the document. When the document is received, the recipient decrypts the digest using the sender’s public key. The recipient also recalculates the hash. If the hash values match, the recipient can be confident that document has not been tampered with in transit. The role of a certification authority is also covered. A certification authority issues its customer with a special file called a digital certificate which binds their public key to identifying information. This video also mentions the importance of digital signatures which it comes to cryptocurrencies. A cryptocurrency such as Bitcoin requires a secure mechanism for updating its decentralised ledger.

[kisme]

this is the only video you need to watch if you want a practical understanding of digital signatures

[ramasif]

This is by far the most simple explanation of the presented concepts - in a way that everyone understands it and from then can move on to the more complicated parts. Excellent.

[seetsamolapo]

Wow! This might be the best video on data integrity and data authentication

- digital signatures rely on asymmetric cryptography.

[kadircangulde]

Such an explanation with downgraded complexity, but with an upgraded realization. Exceptionally wonderful.

[mostinho]

Done thanks
0:15 explaining RSA
1:30 digital signatures: it doesn’t matter what key we encrypt with (public or private) the message can only be decrypted with the other key. A message can be digitally signed by encrypting it with the private key and then others can verify the signature by decrypting with public key.
3:58 digital signature example
5:40 sender hashes the message, encrypts the hash with their private key. Receiver decrypts the hash with the sender’s public key, and if it matches the message then receiver knows message came from sender
7:00 why we need digital certificates on top of digital signatures. Someone could be pretending to be the sender, and digitally signs the message. The receiver has no way of verifying the sender’s identity.
Digital certificates is how the receiver can verify that a public key actually belongs to the sender
8:00 how certificate authority works

[saikrishnasunkam]

This is the single best illustration/explanation of this concept on the internet. Keep making these videos man, you've got talent.

[aVa]

Used this video to get my Sec+ a few years back now... Back to refresh myself on this for my SSCP. Awesome video. Thank you so much!

[ashokantony]

Studying for CCNA Cyberops, the Cisco documentation on this is a complete mess. This video is pure gold, incredibly simple and clear. Thank you sir, keep up the great work . On more subscriber for your great channel :)

[soamesphares]

You have talent to explain concepts...Thank you

[reduser]

2 days on the internet trying to understand this subject, your 11 min video made it, thank you alot !

[billchen]

Amazing teaching. After viewing this video, finally I can understand the concept clearly.

[fromdil]

Thank you for simplifying the concept of digital keys and explaining the role of hashing in it. Your explanation has made it easy for anyone to understand these complex theories.

[aaronstones]

This is by far the best explanation i've ever seen of this. Thanks a lot :D.

[morshedulislamriaad]

You deserve an Oscar for that kind of explanation .

[amir_shayesteh_tabar]

10 from 10! so easy to understand, A good lesson for other YouTubers talking about Digital Signature!

[AliShaikh_]

I love the narration, the humour, the analogies and the simple and easily understandable format. Thank you!

[ITTechTipsYou]

Perfect! At 6:19 I first thought you made a mistake but after finnishing the whole video you carefully explain how a CA works. Brilliant. Thank you.

[jyoti]

It's crystal clear the way you explain and demonstrate with animation.

[ShijenN]

This is the best explanation of digital certificates and digital signature i have come across. Thank you :)

[gittesilberglarsen]

wow! that is very well made. direct, clear and no annoying repetitions