Help Me With Encrypt eSignature Document

How To Encrypt Sign Document

hello friends welcome to my channel on cryptography and digital security part 2 so in my previous video we saw some basics on cryptography keys digital keys what keys are what are the different types of keys symmetric keys asymmetric keys and then we saw how Keys get packaged into something called certificates we saw X dot fireman certificates and GPG certs and we also saw some commands open SSL commands to create keys and package them into certificates so in this second video I intend to cover some advanced topics on digital signatures so we will see how to use keys to generate digital signatures before going on to digital signatures we need to quickly go through some basics on hashing and encryption so we will see these two techniques and how these two techniques we are used to generate digital signatures and at the end of the video we'll see a dump of what a digital signature typically contains alright so let's start with before starting on digital signatures we need to understand two of the techniques which is hashing and encryption so what is hashing hashing is nothing but a mechanism of taking some random input of a free length text and running it through engine churning the data such as so that you generate a fixed length key now the trick is this generation of the key should be consistent so if I give you same texture again and again the hashing function should generate the same key consistently that is one requirement and thus acquire second requirement is any minor change in input should get reflected in the key I mean there should be a drastic change in the output key even if there is a small change in input key good data sorry and third requirement is the hashing should not be reversible in the sense nobody should be able to get the key and from that key do a reverse engineering and get back the data so if you see here in this diagram I have an input data which is a huge amount of text on the right side so so I pass it through a hashing algorithm hashing algorithms are our tools like say sha sha Rifai 2056 our md5 sum so these take input data and generate a consistent output key now we will see it some examples so that things get clear so I have my plaintext so this is my plane takes I generate to generate a hash of this iron say md5 some plain text so this is my hash 80 b-17 $1 habla d7 1e Wi-Fi read on this I get the same ash again and again so let me tweak this file and let me add so let me remove this dot you see this last dot and end I'll just remove it there is a small change which I've done in the file now let me regenerate the hash of this so we have...