Hill Cipher (Decryption)
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- čas přidán 28. 06. 2021
- Network Security: Hill Cipher (Decryption)
Topics discussed:
1) Classical encryption techniques: Substitution and Transposition techniques.
2) Introduction to the basics of Hill cipher.
3) Mathematical concepts to be known in order to deal with Hill cipher encryption and decryption problems.
4) The Hill Algorithm - Encryption and Decryption process of Hill cipher with expressions.
5) Formula for finding the key inverse matrix and explanation of all the parameters involved.
6) Example - Decryption using Hill cipher for the plaintext “RRLMWBKASPDH” with a 3x3 Key Inverse matrix.
7) Finding the determinant of a 3x3 matrix using a short-cut approach.
8) Finding the adjoint of a 3x3 matrix using a short-cut approach.
9) Finding the multiplicative inverse of a number with modulus.
10) Verifying the key inverse matrix.
11) Information about square matrix and unit/identity matrix.
12) Various ways of doing Hill cipher encryption and decryption using Row Vector approach and Column vector approach.
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Music:
Axol x Alex Skrindo - You [NCS Release]
#NetworkSecurityByNeso #Cryptography #NetworkSecurity #HillCipher
Making this video requires more hard work and dedication then the whole playlists available for various subjects on CZcams.
Thanks a lot sir.
At the end of the video, I believe L should be set to "11" rather than 14 in the decryption of RRL to PAY. I spent a bit of time questioning this, as I calculated with (17 17 14) as is written, which failed to produce P. It is written/solved correctly in the calculations, but the formula at this point has (17 17 14). Hope this helps anyone like me who felt like they couldn't do basic multiplication :)
Thanks alot bro was trying to figure it out. Saved me time!!!
Le me : after wasting my 30 mint to figure out how it will be 14 instead of 11 after wasting time my mind figure out let's check comment section now I'm here lol
Btw thanks bro Appreciated 😊
659 mod 26
i felt stupid.
OMG!! I'd been watching a lot of videos and websites but this video explained all very clear!!
That you even explained the linear algebra part in details step by step is admirable!
i am very thankful to you sir for explaining it so transparently ,hats off sir
You are a genius...even for a movement you dint let me confuse thanks a lot !!! Professor
Gosh! Despite my extensive web browsing, this video provided very clear explanations of everything!
That was 3 days of cryptography. Thanks a lot Sir!
i am very happy u r uploading so many lectures
helped me with my maths investigation, thanks a lot.
22:00 I love the way the sir is teaching explaining each and every step 😘😘😍
i have an exam today and this is so helpful, i'll come to say thanks on the reply after the exam...
@27:56 RRL = [17 17 11] but on the calculation took it as 11 so no problem
Nice video overall with detailed explanation. One thing that confused me was the way you wrote the equations in the table at 20:09. on the right side of the equation, it is written 1 * 23 = 23 mod 26, 2 * 23 = 20 mod 26, etc... which can be interpreted as the value of the left side and right side are the same which is not the case in your explanation. Rather according to your explanation it would make more sense to write them as (1 * 23) mod 26 = 23, (2 * 23) mod 26 = 20 etc... and an overall formula of finding the value of inverse of any given number x where there is mod y could be z given x^-1 mod y = (z * x) mod y= 1.
Edit: I feel like the way I wrote the formula could be misleading. I think it would be better if described as:
- an overall formula for finding the inverse of any given number where there is a mod could be
(z * x) mod y= 1, where
x is the original number, y is the mod number and z is the inverse.
nope what he write is correct,
@@kartikforwork My reply also had an some issues which I corrected but how is what he wrote correct?
23 Inverse mod 26 can be found by gcd.
Such a good explanation sir 👏thanks a lot
How ..can you explain please
You really saved me, thanks sir🙏🏻🙏🏻
Really easy and understandable awesome way...
Thanks! Can you do a video on finding the key with a Plain-text and Cipher only for a 3x3 matrix?
thanks a lot , helped me so much❤❤
gr8 sir hope u will upload soon all videos
One question, when I got the determinant of the matrix I got 1154 mod 26 which results in 10 mod 26. how do I get the multiplcaitve inverse since it always end in 0, what do I do?
Thank for ur. Good.teaching 😊
My question is for 26:28
I understand the K x K inverse. But do you multiply these matrices as a whole or each numbers?
Also, how did it end up being the result matrix before you use the mod 26?
Thankyou very much sir ❤🎉
at 21:10 , WHAT WLL BE THE INPUT IF WE PERFORM EEA? I mean, for EEA, the format we do that in is, " a mod b ". So, what will be the values of the 'a' and 'b' respectively for this quetion we are solving in the video?
nothing but the right way of using technology.
what will i do if the multiplicative inverse is not available in modulo 26 ? what is the multiplicative inverse of 4 in modulo 26?
Thank you sir
thx it really helps me
Well done🎉
Thank you!
In some sources and videos encryption formula for hill cipher is given as C=k*Pmod26 and some sources C=P*kmod26, since its a matrix multiplication both the answers are different.. so what should we follow🥺?
c=k*pmod 26 is right one
Sir may I know the 13 inverse of mod 26???? If no multicative ..then how will solve this problem sir ??? Please tell because my internal qstn the qstn mtrx 19 is differ in 9 ..so using this method u guide 13 I get detk ...so what can I do sir ????
Thank a lot sir!
Thank you❤
why we need to take the modulo while finding determinant and adjoint, we are taking modulo at the end?
I have a doubt why we need to take mod 26 always after adjoint and u also took mod 26 after determinant and also again after inverse plz clarify my doubt
I think its because we have 26 letters in English alphabet
Once we complete 26 alphabets, we go back to the beginning.
Thats the reason for that i guess.
did you understand it? pls explain if you did?
Be cause of total number of alphabet is 26
Is there any shortcut to find multiplicative inverse of a number
Sir kindly upload rest of the videos as soon as possible
there is a little mistake in 27:54 RRL --> (17 17 11 ) not (17 17 14 ) and thank you very much sir
hi bro nice teaching ,but i have one doubt that is in inverse is odd(20:29) instead of even ,what we can do bro? how to find that value??
I'm stuck in my calculation, can you help me out, My determinant is 8 and its multiplicative inverse does not exist under mod 26, What should I do?
Thanks genius.
While it is 3×3 matrix you just copied 2more columns & 2more rows, but what if its 2×2 matrix then how to do sir
plz upload whole syllabus
@ Neso academy we are getting different cipher text when we use KP approach ..
does that mean we cant find multiplicative inverse mod 26 of even numbers? because whatever is multiplied with even number can't result in odd number and hence 1 as the remainder.
I do not know the particilarities of mod26, but in mod 6 you have the matrix [ 2, 3; 3 2 ]. Even though no element is inversable in mod 6, the matrix itself is inversable.
Maybe same matrices can be found in mod 26.
thanks
16:40
There is a big deffrence acording what you explan
awesome
Sir in ist row instead of 17 there is 7 at 2nd place in ist row plz correct this becoz key is same for encryption and decryption
12:20 what if its 2X2 matrix or some other
what if i cant calculate the multiplicative inverse? i got K^-1= 24^(-1) * matrix * mod 26
OMG, maths 🤯. got me confused, what is all this modulo modulo going on
Sir upload the video of control system ✅
Sure. The next lecture is coming soon.
@@nesoacademy your videos are very helpful but can you please tell name of application you use for java ?
😊😊😊😊 very happy
Hello, please help explain to me how the 23 became 17 more simply. 🙇♂🙇♂ Thank you!
adjoint of k could be calculated in calculator.
if any one knows the steps pls paste the link.
VALUE OF L = 11 DURING THE DECRYPTION OF RRL NOT 14 🤣 and funny part is my faculty also do the same mistake but her total somehow match's the correct total 🤣🤣
great
What if the total letters is not a multiple off matrix size .??
i.e if text was neso academy and matrix size was 3x3 then how to breaj the letters??
Insert a filler character X
nes oac ade myx
@@tamillenin2276 Something like padding?
sir why you put mod 26 after calulating mod,it should go off ryt?? ,that make me confuse,
It is taking everytime so that the result cannot exceed 25.
There are 26 letters in english language.
sir if the key value matrix is not given in the question ,how to find the key matrix sir.reply soon.
Key must be provided.
Why including mod function while doing diterminant
Isnt the formula C= K*P mod 26 not P*K mod 26??
There is the small mistake in place of 14 there must be 11 I hope everyone can see that.
L=11 at 28.02 mistaken
how to get a reminder sir?
Easy to learn but difficult to do
❤️
Thalaiva , you are great 👌
The ending part was not explaind properly
I am once again asking for the code, please
By mistakely it written as 14 instead of 11
why do you mod everytime. can't we find 1/det(k) and adj(k) [without mod by 26]. Multiply 1/det(K) and adj(k) then mod by 26.
we applied mod 26 on det k and now we have also applied mod 26 on adj k. since applying mod 26 on both detk and adj k, how will mod 26 still remain to be used in the k inverse equation ? Please tell if you have understood coz i dont understand it.
Op🔥
YALLAH Y AJ PAPER MA NA AYE.AMEEN
How did you get multiplcative inverse of 23 as 17? Shouldn't it be 1/23? I am very confused. Someone pls help.
Sir -936 mod 26 =0
Bro is that wrong I am also getting the same reminder .what did you do ?
it'd take 10 mins in the exam just to find the inverse
😮
gottcha.
First view first Comment
bhai ye tera adjint kaise nikala hai vo bilkul bhi samajh mai nahi aaya.
Make new video to understand the concept
End of brain
billa
9:48 -936 mod 26 = 0 @nesoacademy
But we get -939 mod 26 okay it's mod value is-3 and it is in negative so we add 26 then 26-3=23😅