What is digital signature?
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- Опубликовано: 19 окт 2024
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A digital signature is equivalent to a handwritten signature in paper, and a digital signature serves three basic purposes. Digital signature is commonly used for software distribution, financial transactions and other cases where it is important to detect forgery. Digital signatures are very popular with e-mail users.
In this video, I will talk about the digital, uses, and the whole process of creating and sending digitally signed document over the Internet.
Keep in mind, digital signature is not about encrypting document, just like paper-based signature.
Playlist: Basic Cryptography
• Private Key Encryption...
Advanced Cryptography:
• What is digital signat...
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Sunny Classroom
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the entire semester i did not understand this but only 5 min i got it, thank you Sunny
Sunny, I just wanted you to know that today I provisionally passed SSCP and I would have not achieved it without your youtube lessons. You are the best teacher any student could hope for!
congratulations! I am so glad to hear it.
share your experience while achieving SSCP
Great explanation! Thank you! I only want to add that the reason we use a hashing algorithm before encrypting a digest, is to make the digital signature small. Because if the plain text message was 10GB in size, then using a hashing algorithm on it creates a small string of only a few bytes. But we if created the digital signature from the entire 10GB text message, then we would have to send 20GB worth of data - 10GB for the original message, and another 10GB for the digital signature used to verify that it was signed by Bob. In case anyone else was wondering why we use a hash algorithm to create a digest, before encrypting it with the private key to create a small digital signature. Remember, if any small change was made to the original message, the digest would be completely different, and that's why we can use this method to decrease the size of the digital signature.
Good to know!
I was so confused and I was exactly looking for an answer of that question in the comments section. Thank you, you are a legend.
ruclips.net/video/0F7Z7LXsR0g/видео.html
Do you have Digital Signature ????
I can’t believe I didn’t stumble upon your videos earlier while studying for the CISA. Domain 5 has had some difficult concepts to understand and taking even 30 min to watch a few of your videos has finally made concepts click. Thank you so much, you’re a wonderful teacher!
You explain this better than anyone, Sunny. We are so blessed that you are on RUclips. There are ones that talk for 1 hour and don't explain it as well as you have in 5 minutes. Thanks for explaining it so well!!!!
Wow, thank you!
Woah my book fails to explain this in 5 pages, what you did in just a few minutes.
The same here, his explanation make the subject very ease.
exactly!!
Exactly
@Matias Gatlin Since she is your girlfriends & you know in & out about her , then what made it necessary to hack her account
bro can u send me yr book and help me do my thesis if u don't mind?
Sunny, your explanations are spot on.
In your Public key video, you made clear, that the process starts with the receiver. Here you pointed out, that digital signature and encrypting the message are two distinct things.
I watched a ton of videos to understand those concepts. No one made these differentiations. Hence, they are critical for the understanding.
Thank you very much for your work.
Thank you Sunny! I was preparing myself on your channel for the cryptography exam for my dream job. I got the job and I explained digital signature, hash functions and PKI exactly the way you do on your channel. Thanks to you I had the best written exam among all the participants. Keep doing the great job!
I am happy for you and congrats on your new job. I will do my best. Come back to channel sometimes and suggest new topics for me. Congrats again.
@@sunnyclassroom24 I certainly will. As you asked me for a suggestion, I would love to see you explain how some of the cryptographic primitives reside in the crypto asset world. i.e. how did Bitcoin protocol made use of digital signature, or explanation of some more advanced techniques like ZKP and how the zkSNARKs are made and their components or cryptography behind Mimblewimble protocol. Have a nice day sunny and please don't forget to enjoy yourself!
interesting that 5 mins in a free video from someone who speaks english as a second language is more helpful than a $500 textbook and a lecture from an expensive institution..
Thanks Sunny, you're awesome
I am reading from the book, it took me hour to barely understand, five minutes video goes directly to the point, thanks Sunny!
Great to hear!
you explain it very well - the logic is sound and easy to follow unlike some people that gets trapped in the technical details before explaining the basic steps
At 4.20, he debunks one of the digest confusion peoples are running into - a digital signature is NOT used to encrypt application data. Great job Sir!
You are welcome !
Sunny, you are a treasure! I'm so grateful I stumbled upon your channel. Your explanations and visuals break the topics down so that it's so understandable. Thank you, thank you, thank you!! 🙏🏻
I love this guy's videos. Simple and clear.
It's embarrassing how little I understood about this, and remarkable how clear this video makes the subject. Well done.
You can explain the most complex concepts so that anyone can understand. Thank you very much
You are welcome.
After watching tons of videos... finally I was able to understand the concept after watching your video..thanks alot sir
You are welcome! I am glad that it helped.
today there was my ppt i was very upset how to explain. Then i pray O Allah help me and finally i watch your video . Thanks to my Allah ..
Thanku sunny everything is crystal clear..
You are amongst the best teachers who had in my whole life; you are the best best. GOD Bless you, Sir.👏👏👏👏
It took me several years to understand this simple process. Thanks, Sunny.
It was a very elaborative with example which i struggled a lot studying books and youtube it to clear my confusion. I appreciate the way you explain straightforward and simple.
I have understood a lot.tqsm sir.today I have my exam.it helped me a lot
bob and alice using cryptography techniques again!!! they are amazing lol
You make any topic so simple yet clear. Thank you very much Sunny, I have always referred to your videos when in doubt.
Sunny, I hope you the best cause you are the best teacher on Earth. Thank you!
Mostly i never comment the videos i see, really worth for watching and got full concept in just 5 mins. Really it's useful
Would like to appreciate few things
1. Very nice pace and clear explanation
2. Using Diagrams
3. Talking about confusion at last
4. Using "Namaste" symbol at end :-) . I am Indian and it is in our culture to say goodbye or hello. Cheers!!!
Dear Mr. Sunny. You are amazing at explaining things. FANTASTIC job, a million thanks!!!
You are very welcome
This is what our newbie need,
Im studying Network+ and those materials im using just lead me to a very frustrated situation ,
but your explination really straight forward and newbie friendly .
Thanks you Sunny,
pls keep your channel updating and introducing more ,
i have subscrbed .
Thank you for sub!
I must thank you sunny for wrapping up the whole topic meant for 1 and half hours in just 5 minutes. It was really educational and useful.
Your videos make such complex stuff so damn easy to understand!
Your explanations answer questions which even whole of the web can't.
Thank you very much for your encouraging words. I will try my best to live up to your kind words.
okay, third video today, I'm officially addicted to your channel :)
Thank you very much! I appreciate it!
I think you have just literally saved my life. Your demonstration and explanation have helped me so much in understanding these ALIEN computer language. I mean, English is my second language already and these computer languages were too hard for me to comprehend....Until viewing your videos. Thank you so much sunny.
You are very welcome! I am glad I could help. English is my second language too and thus pictures and diagrams always help to understand better than just words. That is why I do this to help others.
Sunny Classroom your language is Perfect to me and the pronunciation is very clear. Your explanation is straight to the point. It is done well constructed and very logical. Concise and clear. Just what I want. Keep up the great work.
The world is better with your contribution💚
Many thanks for your encouragement. Best wishes, sunny classroom.
Excellent Illustration on Digital Signature !!. it is like Juicing an orange and giving everyone an Orange Juice which is a solid understanding of digital signature. Appreciate sharing your know how Sunny !!. Thanks again. Mat.
Clear! Correct! And to the point! Very pleasant and educational to watch.
Many thanks for your encouragement.
Finally I've managed to find a youtube video on this topic which makes complete sense thank you. The graphics explained this very well and now i understand at last
this guy is really good at explaining everything
amazing video, better explained than almost all books that i read about it
simplest explanation of complex topics salute!
Thank you for watching!
Sunny, you are my favorite. You are making it easier for me to understand things.
Bob, I agree with the other positive comments. This is the absolute best explanation of digital signatures with email or memo that I have seen. Great job and thank you for this. 👍🙌
Fantastic short and concise videos descriping very complex concepts ;)
You got my subscription!
Many thanks , Casper, for your great comment and your subscription.
Mine as well 😊
Sunny, this is explained very clear and crisp. And common confusion is best explained. Thank you.
I am glad to found out your channel. You really explain the complex topics in a simple, clear and concise manner. Your videos helped me understand the Assymetric encryption topic well. Thank you so much :)
You are welcome! I am glad it helped.
Professor Messor,David L.Prowse, Darril Gibson and Jason Dion couldn`t break it down like you just did. Thank you.
Mr. Sunny, the contents of your youtube account are valuable. It was nice to find you. Please keep doing what you have been doing.
Many thanks.
Thanks for explaining this and other topics so clearly! I have watched lots of other videos by professors, experts and students but they all miss the point. You explain this and other topics so logically and clearly that it's a pleasure to watch. Thank you so much!
Somewhat simple concept, but hard to understand just by reading textbooks. Thanks for this vid.
Very good explanation. Also the last remark about data encryption is very clear.
Thanks a lot for your feedback.
Great video which will explain the functionality of digital signature without any complexity
WOW, what an awesome explanation and diagram........and you anticipate the confusion some can have with the message vs signature encryptian
Thanks a lot.
I bought a class on Udemy teaching this, but you're explaining it way better!
Thank you for your time! Check out my other videos please!
@@sunnyclassroom24 of course! I like to use your channel as a cross reference for any topics that Udemy confuses me with, but with your presentations I understand it a lot more, thank you :]
@@andrewalonsi You are welcome!
Simple, clear and very easy to understand. Very effective presentation. Thank you
You are welcome! And thank you for your comment.
OMG! I DON"T BELIEVE THAT I"VE FOUND THE GREATEST EXPLANATION! THANK YOU SO MUCH!
Glad it helped!
There is a problem that I could not understand until I watched your video about why the receiver can recognize who the sender is while everyone can have a public key. Thank you so much.
Good stuff man! You made this concept crystal clear
This is amazing, didn't know cryptography was so beautiful
Thank you for watching!
Your explanations are incredibly easy
It couldn't be more clear. Great explanation.
Thank you!
2 hours of my professors lecture could not explain me so easily as a 5 minute video!
A very good, clear, and simple explanation. Thank you very much.
Thank you so much Sunny for the time you put in creating these awesome educational material. God bless you.
My pleasure!
Mr.Sunny I have a question.In Public key Asymmetric method the receiver(ALICE) is the one who has to create keys and share them to Sender correct, in this i see you mention that BOB is sharing both keys, i am bit confused.
Finally understood digital signature after many videos. This is the best .
Thanks a lot for your nice comment. I am glad it helped.
Your lessons are more than perfect... thank you from all my heart.
Keep going on.
almost 100's of video are there in you tube. Your explanation was so great.
120 videos by now.
I would say an excellent explanation. Neat and clean with visuals
Many thanks, Tariq for your watching and leaving comments.
Great video mate. The video covers all the key points and is quite easy to understand.
Thank you Sunny! This cleared up some confusion I had about this topic, so glad to have found this explanation.
Your way to explain is best till found in youtube , Thank You Sunny Class Room
You are welcome, Abad.
Thank you for explaining this. I could understand this clearly after watching your video.
very simply explained! thanks Sunny !
You are welcome Vikram! And thank you for leaving comments.
This guy is good at teaching!
Thank you for watching!
Man, I really liked this video and I instantly subscribed to watch more later. I guess what I am hung up on is thinking about where all of this hash comparing is taking place. It must be done behind the scenes.
thanks for your kind words. Yes, you are correct. A lot of things are happening without user's knowledge.
That was an awesome ,simple & vivid explanation !
Thank you for leaving nice comment.
@@sunnyclassroom24 I've questions, what is your email ?
Awesome, well done my friend Sunny! This video will be full recomended to my friends.
Thank you very much for your kind words and encouragement. I hope your friends would also like it.
One of the few videos that properly explains digital signatures; good stuff..
Only question I have is at 2.35 you state that bob encrypts using his own private key.
is this best practice ??
If bob encrypts using his private key then by design, the decryption key would be public (his own public key).
Surely you would not want a decryption key to be public... decryption keys must be kept secret...?
Unless this is the method used for signing...
I am thinking that Bob should actually encrypt using Alice's public key...and Alice would then decrypt using her own secret private key..
Private key is used for Non-repudiate property so that Bob can't refuse it doesn't send the message to Alice. This is the reason to use Private Key at sender side.
Hi, my friend, many thanks for your comment and question. You are correct in terms of public key encryption.
In this video, Bob uses his private key just for signing the document. The document itself is still in plain text. Thus, as you said, it is not a best practice.
Suppose they want the document encrypted. Alice( the receiver) would generate a separate pair of keys. She keeps her private key and sends Bob the public key and he would use it to encrypt his document
Thus, digital signature and public key encryption are just "opposite" in terms of private key and public key.
To encrypt the document, the receiver generates a pair of keys: public key and private key. The receiver keeps her private key and public key is used by the sender. The sender uses public key to encrypt the document and the receiver uses her own private key to decode the document.
To sign the document (digital signature), the sender generates a pair of keys. He keeps his own private key and the public key is sent to the receiver.
In this video, we only focus on digital signature. Thus, the document is still in plaintext. I have another video: public key encryption explaining how it works.
Many thanks again. I hope I could be helpful in explaining two different cases.
Hi, thanks so much for explaining, really helpful. I hope your channel grows fast because it is great!!!.
@@sunnyclassroom24 Thank you . Well explained.
Sunny Classroom ... so in other words, Are you not allowed to use this same pair of keys for encryption and for digital signature ?
The best description of this topic I have found, very helpful, thanks very much!
Really great, concise explanation and was great in combination with your video on Public Key Encryption to wrap my head around this concept better
Hours of lectures this teacher explained the digital signature in 5 minutes. I don't know why im going to college
you never ever disappoint. always the best explenation. You pointing out the common confusion also helped a lot.
Crystal clear now. Many thanks, you are a great teacher.
A very precise and simple explanation...thank you!
thanks.
Very simple and concise explanations thank you very much
Thank you Sunny for this vivid explanation . I have two questions: (1) Alice could decrypts Bob's digest . This means anything Bob's encrypts with his private key is not safe because his public key is available to attackers, right? (2) How can we be sure both Bob and and Alice are using the same hash algorithm? a digital certificate?
Hi, my friend. Thanks a lot for taking time to ask these two questions. these two questions are excellent because you really touch two very important questions. 1) difference between digital signature and public key encryption; 2) hash algorithm.
Question 1: Yes, indeed, anyone can get Bob's public key, and can use his public key to verify one fact: the signature is Bob's signature. However, what harms does it cause? An analogy in life: I send you a letter through the US post office, you get my letter and you knows it comes from me simply because you know for sure it is my signature at the end of the letter.
What you really concern is actually the document itself because the document is still in plain text in my video.
Suppose they want the document encrypted. Alice( the receiver) would generate a separate pair of keys. She keeps her private key and sends Bob the public key and he would use it to encrypt his document.
Thus, digital signature and public key encryption are just "opposite" in terms of private key and public key.
To encrypt the document, the receiver generates a pair of keys: public key and private key. The receiver keeps her private key and public key is used by the sender. The sender uses public key to encrypt the document and the receiver uses her own private key to decode the document.
I hope my answer would be a little bit helpful or cause more confusion.
2) the second question. It is very technical. I am afraid at this point that I could not be able to explain. There are some common hash algorithms, like MD5, MD6, SHA-1, SHA-224, SHA-256, SHA-384, SHA-512, Wirlpool, and many others. When mail servers communicate with each other in terms of using digital signature, there must be a mechanism to know what type of hash algorithm is used. The analogy is like meta-data for HTML. The web browser knows what version is used by reading document type.
I would definitely get back to you once I find the correct answer.
I would appreciate your questions, which would definitely motivate me to research in this area.
wow, beautiful illustrations and explanation....very simple
Thank you for the terrific video. Great job Sunny!
You are welcome!
best video in the history of youtube thanks
Best explanation for Digital signature!!
This channel is amazing. I subscribed right away!!!
Thanks. Beautiful and slow explaine made it easy to understand.
Glad it was helpful!
Hi, this is really really helpful. I can't tell you how much this video helped me.
I am glad it is helpful. Thanks a lot for taking time to leave comment.
Nice one I'm about to get in Information System Security Exam in an hour, I really do appreciate.
I hope everything goes well.
Very nice channel. Clear and short videos - you can mix it for understanding what you want. Thanks!
thanks for explaining this concept in such a concise way.
authenticity - the recipient can verify the identity of the sender
integrity - the recipient is unable to invent or modify a document signed by someone else.
non-repudiation - the sender can not deny that he signed a document (non-repudiation)
This guy makes my day..nicely explained ...thanks dude
You are welcome
Sir explained too good my exams are near of final year and this helps😊
Happy to help
Very easy to understand, sir. Thank you very much.
you are welcome
Today, I want to clarify my lesson on hash function, and I am now referring another of your video. What school do you teach, sir? I am a freshman in Software Engineering and wanting to be an ethical hacker. Do you teach ethical hacking or do you have any suggestion so that I can improve more in that field? You teach very well, sir. And I am glad to know you.
I am teaching Computer Information Systems with University of Saint Mary, Leavenworth, Kansas. I don't teach ethical hacking. In RUclips or Udemy (paid) there are many lessons about ethical hacking. Lessons are not expensive, normally about $10.
Extra ordinary Teaching style you have !