Symmetric Key Cryptography: The XOR Cipher

This is the fourth in a series about cryptography; an extremely important aspect of computer science and cyber security. It covers the XOR logical operation, that is the exclusive OR operation, explaining how it can be used to encrypt and decrypt a sequence of binary digits. XOR is an important process that is employed by many modern day ciphers. Using a spreadsheet, this video demonstrates how the XOR logical operation can be applied to a single character ASCII code to encrypt and decrypt it using the same symmetric key, and the same method.

[marshall]

coming from a professional procrastinator, this video was very well put together and easy to follow. thanks a lot!

[s.garabet]

This was very well explained. Thank you. It amazes me how some modern textbooks are written by people who likely can't even explain the concepts in person.

[weslaycock]

First time I was able to put the XOR decryption process to practice, feels good thank you.

[joykou]

and you also explained the name of 'XOR' . shouldn't we know the nature of a thing and then learn how to use it.
it's really a good way to learn everything!

[inarisound]

This channel is a goldmine, thank you so much for your extraordinary work!

[joykou]

it's really a wonderful video explaining xor and encryption. compared with all other ones i watched this one just makes everything simple and easy for understanding.
thank you!
and i'm looking forward to more videos from you!!

[estellamariegulles]

Your explanation is unquestionable and I like how clear your voice is, keep it up! I've subscribed :)

[latedeveloper]

2:38 Encryption using the XOR function
2:42 Break down into separate cells
2:50 Any random sequence of 8 bits for the secret key
3:20 Applying the key comparing pairs of bits using XOR operation
3:50 Write 1 if they are different, "1 or the other is a 1", or "exclusively a 1".
7:00 Binary to ASCII in Excel
7:12 ASCII to Letters in Excel.
7:30 Practice exercise

[kayquer]

Thanks for the effort in making this video. It really clarify and thought us how to think about symmetric cryptography. 👏🏻

[hecker]

well summarized and easy to understand, nice video!

Here's the answer (spoiler!)

decrypted binary -> 01111010 01101001 01110000
decrypted ascii -> zip

[belatcradus]

Well done.
Thanks for sharing your knowledge with others.

[billchen]

Beautiful explanation, thank you very much.

[TheRengade]

Simple and easy to understand. Thank you.

[semiileka]

encryption is achieved by the function Y= E(K, X). using this function and given the key 1010011001, encryption the message 0011011 using the AND principle.

[sengi]

btw you make excellent videos! Are you involved in cyber security or computer engineering in any way?

[angrysunshinebandit]

what would happen in a situation in which there is an 8-bit symmetric binary encryption key, but a 16-bit binary value to encrypt using the XOR method.

For example with a credit card number, turning each of the individual digits into 4-bit binary values, then combining every 4 into 16-bit chunks then encrypting them.

[m.alaiady]

if you guys wondering what was the result of encrypt the letter 'z' it was '/'' :)

[xavierarana]

can you do this without using binary digits? Like just with the original ASCII code?

[JohnSmith-eosp]

The Vernam Cipher introduced this concept when it was patented in 1919