How to verify the modulus of the CSR,Private Key and Certificate

To verify that a private key matches its certificate we need to compare their modulus.

First move to the directory,where you placed your SSL certificate.

ls

How to convert PPK file to ssh remote server in ubuntu

To convert the ppk file into openssh standard, we need to install the puttygen tool:

sudo apt-get install putty

Here is the ppk key that we want to convert:

Public-Key Authentication in SecureCRT

Public-key authentication is a proven, it’s better then allowing password authentication.As long as you keep your private key file safe, you’re less likely to encounter a break-in of your Unix/Linux servers. In this tutorial, I’ll try to show you the steps that you need to create public/private key using SecureCRT and use it with Ubuntu Server.

To create a public/private key pair in SecureCRT, open up SecureCRT, click on “Quick Connect“, from there click on the “Properties“:

Note: Uncheck all other options

Click “Create Identity File…” and the key generation wizard starts:

 Click “Next” to get started:

Select RSA as the Key Type and click “Next“:

Next, you are prompted to enter a passphrase twice (I leave it blank, but you should use something pretty long phrase, that you’re going to remember):

Next, it will ask you for your desired key length in bits. Take the default “1024” and click “Next“:

Now, you need to move your mouse randomly to generate some data to encrypt the key pairs:

Once it has been generated, click “Next” then you will need to save the public key and private key to your computer. Save it in a safe place!

Click “Finish” When asked whether or not you want to upload the following key, say NO!

Copy the public key into your home directory using WinSCP:

Login to your Linux server with your username and password and cat the content of the public key:

cat Identity.pub

First you need to format the public key properly, for this you need to delete the first four lines as well as delete the last line, and get JUST the key on a single line with “ssh-rsa” in front:

cat Identity.pub

Note: Open the file with “nano <public key filename>” and you will be able to edit it properly.

Create the “authorized_keys” file inside .ssh folder and set the permission on it:

touch .ssh/authorized_keys
chmod 750 .ssh/authorized_keys

Important Note: If .ssh folder doesn’t exist then you can use these command to create it!

mkdir ~/.ssh
chmod 700 ~/.ssh

Now that the RSA key is properly formatted, you can add it to the “authorized_keys” file.

cat Identity.pub >> .ssh/authorized_keys

Remove the public key (In this case, it is Identity.pub):

rm Identity.pub

Connecting via SecureCRT using your key pair:

If this is the same session you were already working with above, your identity file should already be filled in…if not, just click the browse button “…” and find your private key. Click “OK“. (You can also refer this link for more help):

It will not ask for the username and password

Hope this will help you!

Please Remember me in your prayers!

Enjoy 🙂

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Key-based ssh logins with PuTTY

Open your PuTTY Key Generator, it was installed when you installed PuTTY!

Click Generate:

You will need to move your mouse randomly to generate some data to encrypt the key pairs:

When the private/public key pair has been generated then you will need to save the public key and private key to your computer. Save it in a safe place!

Login to your Linux server with your username and password and enter the following commands:

mkdir ~/.ssh
chmod 700 ~/.ssh
nano ~/.ssh/authorized_keys2 

Paste the public key into your file. It may paste over in 3 lines, make sure its on a single line, this is very important!

Now to make that file accessible by only the user:

chmod 600 ~/.ssh/authorized_keys2

Now we shall create & save the session in PuTTY:

Select the Data and fill in the Auto-login username field, with the username for which you created the key:

We need to tell PuTTY to use a Private Key File. Select SSH->Auth-> Browse and point it to your private key:

Now we shall try to connecting via PuTTY using the saved session:

It will not ask for the username and password 🙂

Hope this will help you!

Please Remember me in your prayers!

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