Have you ever used SSH key yeah I'm sure you have used while using Git or while
accessing the network but do you really know how SSH key works. so let's explain
this with an easy example but before going to the SSH key working let's first
see what is SSH? SSH stands for Secure SHell and what it is ? it is a
cryptographic Network protocol but what is that mean? protocol-> think about
protocol as rules of transferring encoded data over the network
that's why cryptographic network protocol that's okay
but where this SSH used for? it is best used for accessing the remote servers
when you use this SSH key and you will get the command-line interface of
the server it's just like you sitting in front of the server which is situated
far apart you. So how this SSH key created. Actually SSH uses Asymmetric
cipher and what is Cipher? Cipher is a algorithm for performing encryption and
decryption that means a function which perform encryption and decryption that's
okay but why we need this SSH yaa we have the username password to log into
server but why SSH key because username and password can be stolen in the middle
the symmetrical encryption cannot be done on the remote server if you not
familiar with the symmetrical encryption let's first understand this because SSH
key uses Asymmetrical so we must have the knowledge of Asymmetrical and
symmetrical so symmetrical encryption is simply a one function which is shared
between two people and that function is single capable of encrypting and
decrypting the data sent along this means suppose
if I want to say ABC and that meaning is ZYX
then as sent to you this means you get the point okay you just have to reverse
the alphabetical order so if I send you ZYX you will
probably know that the function that the data actually is ABC but to perform this
action you and me both have the same cipher same algorithm or the same
function which is simply reversing the alphabetical order but here comes the
great problem because SSH key used for accessing the server which is remotely
placed placed far far apart from you and then problem comes with the symmetry
that how will you even share that function share that's safer because even
that cipher can be stolen and can be used by someone else in between so here
comes the great solution for symmetrical the Asymmetrical encryption our
symmetrical encryption uses a pair of key that means the public key and the
private key as the name suggests private key is a private we will not going to
share with anyone even not going to touch it
and the public key is accessible to anyone we share this with anyone we say
ok get this public keys you have this public key and if you want to contact
with me just encrypt your data with my public key and then anything which is
encrypted via your public key can only be decrypted by a private key remember
this this is very important and there are many encryption method RSA DSA ed25519
but in whole Asymmetric encryption one function is for encrypting the data and
another for decrypting so we share but public one as a encrypter and we keep
the private one as the Decrypter so now comes how SSH key works so you have a
private key and you have a public key and you want to access the server
so how you will perform this action so let's see from your local computer you
want to access the server but firstly you have to verify yourself so what you
do you will pass all the public key you have on your system to the server ok
because public key can be shared with anyone so there is no problem sharing
the public key - server then on these public Keys server identify if server
already has your public key registered then if it found then servers say ok now
let's verify yourself and after that server creates a new key it's a top
secret and now server encrypt that key with your public key remember you have
given the public key and with that public key server encrypted the top
secret key and then pass over to you again then because you have the private
key and you can unlock this you unlock that data and you got that top secret
and pass again over to server server know that yeah and this is the same
thing I have sent to you via your public key encrypted form and then
server says great you are verified and after that the ssh system creates a
tunnel between the local computer and the server and we can easily pass our
encrypted data along this tunnel this is a system but how this system can be used
so we have various ssh clients on our various type of machines like on mac OS
or linux they have built in terminal for Windows users you can use putty and
Android juice as a search and iOS has the prompt in it but you know every
great thing has some problem and SSH key has also because it's a service so it
cannot be available until you start the system so that's the great problem but
if you by mistake misconfigure or of any kind of access then you can't login
back one more problem is that if you forgot or if you delete it by mistake
the private key what the purpose of sending the public key to anyone because
you cannot decrypt any data so these are the things you have to keep in mind
while using SSH key but SSH key is a great help in passing data over the
networks and I think you have easily understand SSH key and it's working so
if you have any doubt feel free to message me and they don't follow to
share this video to everyone so that everyone get what SSH key and how it
performs the encryptions over the network so don't forget subscribe and
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