Jul 06, 2018 ssh-keygen will create a public and private key pair for use in authentication. The private key is stored in /.ssh/identity, whereas the public key is stored in /.ssh/identity.pub. The public key must be placed in /.ssh/authorizedkeys of the remote machine in order for the setup to work.

Simple: It is the fingerprint of a key that is verified when you try to login to a remote computer using SSH. When you log into an SSH server for the first time, you'll see something like that shown in Figure A. You have to accept the fingerprint before the SSH connection can be made. Obtaining host key from PuTTY. If you already have the host key cached in the PuTTY SSH client, you can import a PuTTY stored session to WinSCP, including the cached host keys. Make sure the Import cached host keys for checked sites option is checked when importing the sessions. Because fingerprints are much shorter than public keys, they're also much easier to inspect and compare even through the naked eye. How to use public key fingerprints. The first time a user connects to your SSH/SFTP server, he'll be presented with your server's fingerprint. You can put the server keys fingerprint in DNS (Domain Name System) and get ssh to tell you if what it the two fingerprints match. This is not a guarantee but it makes Mallory's job harder since he needs to spoof DNS as well as ssh, which can be done as few domains yet implement DNSSEC. Ssh-keyscan prints the host key of the SSH server in Base64-encoded format. To convert this to a fingerprint hash, the ssh-keygen utility can be used with its -l option to print the fingerprint of the specified public key. If using Bash, Zsh (or the Korn shell), process substitution can be used for a handy one-liner. Generate SSH Key using PuTTYgen. With PuTTYgen you can generate SSH key pairs (public and private key) that are used by PuTTY to connect to your server from a Windows client. The private key will be stored on your local machine, while the public key has to be uploaded in your dashboard. When connecting with PuTTY.

Several tools exist to generate SSH public/private key pairs. The following sections show how to generate an SSH key pair on UNIX, UNIX-like and Windows platforms.

Generating an SSH Key Pair on UNIX and UNIX-Like Platforms Using the ssh-keygen Utility

UNIX and UNIX-like platforms (including Solaris and Linux) include the ssh-keygen utility to generate SSH key pairs.

1. Navigate to your home directory:
2. Run the ssh-keygen utility, providing as filename your choice of file name for the private key:

   The ssh-keygen utility prompts you for a passphrase for the private key.

3. Enter a passphrase for the private key, or press Enter to create a private key without a passphrase:

   Note:

   While a passphrase is not required, you should specify one as a security measure to protect the private key from unauthorized use. When you specify a passphrase, a user must enter the passphrase every time the private key is used.

   The ssh-keygen utility prompts you to enter the passphrase again.

4. Enter the passphrase again, or press Enter again to continue creating a private key without a passphrase:
5. The ssh-keygen utility displays a message indicating that the private key has been saved as filename and the public key has been saved as filename.pub. It also displays information about the key fingerprint and randomart image.

Generating an SSH Key Pair on Windows Using the PuTTYgen Program

The PuTTYgen program is part of PuTTY, an open source networking client for the Windows platform.

1. Download and install PuTTY or PuTTYgen.

   To download PuTTY or PuTTYgen, go to http://www.putty.org/ and click the You can download PuTTY here link.

2. Run the PuTTYgen program.
3. Set the Type of key to generate option to SSH-2 RSA.
4. In the Number of bits in a generated key box, enter 2048.
5. Click Generate to generate a public/private key pair.

   As the key is being generated, move the mouse around the blank area as directed.

6. (Optional) Enter a passphrase for the private key in the Key passphrase box and reenter it in the Confirm passphrase box.

   Note:

   While a passphrase is not required, you should specify one as a security measure to protect the private key from unauthorized use. When you specify a passphrase, a user must enter the passphrase every time the private key is used.

7. Click Save private key to save the private key to a file. To adhere to file-naming conventions, you should give the private key file an extension of .ppk (PuTTY private key).

   Sims 3 island paradise key code generator. Note:

   The .ppk file extension indicates that the private key is in PuTTY's proprietary format. You must use a key of this format when using PuTTY as your SSH client. It cannot be used with other SSH client tools. Refer to the PuTTY documentation to convert a private key in this format to a different format.
8. Select all of the characters in the Public key for pasting into OpenSSH authorized_keys file box.

   Make sure you select all the characters, not just the ones you can see in the narrow window. If a scroll bar is next to the characters, you aren't seeing all the characters.

9. Right-click somewhere in the selected text and select Copy from the menu.
10. Open a text editor and paste the characters, just as you copied them. Start at the first character in the text editor, and do not insert any line breaks.
11. Save the text file in the same folder where you saved the private key, using the .pub extension to indicate that the file contains a public key.
12. If you or others are going to use an SSH client that requires the OpenSSH format for private keys (such as the ssh utility on Linux), export the private key:
    1. On the Conversions menu, choose Export OpenSSH key.
    2. Save the private key in OpenSSH format in the same folder where you saved the private key in .ppk format, using an extension such as .openssh to indicate the file's content.

A lost SSH public-key or a web service generates an SSH key but does not provide the public-key part to you. What to do now? There is a solution for this situation.

When you have an SSH key you need the public key to setup SSH passwordless login with SSH-key. But if you have lost the public key part but still have the private key, there is a way to regenerate the key.

With the public key missing, the following command will show you that there is no public key for this SSH key.

The -l option instructs to show the fingerprint in the public key while the -f option specifies the file of the key to list the fingerprint for.

To generate the missing public key again from the private key, the following command will generate the public key of the private key provided with the -f option.

The -y option will read a private SSH key file and prints an SSH public key to stdout. The public key part is redirected to the file with the same name as the private key but with the .pub file extension. If the key has a password set, the password will be required to generate the public key.

To check the details of the generated public key execute the following command as shown above.

Private Key Bitcoin

The output of this command shows the key size as the first column, the fingerprint as the second column and after the file name, the type is shown in brackets. In the example above, a 4096 bit RSA key.

Generate Ssh Key

Read more of my posts on my blog at http://blog.tinned-software.net/.

Public Private Key Encryption