Jan 26, 2018 Secure Shell Version 2 Enhancements for RSA Keys. Cisco IOS 15.0(1)M Cisco IOS 15.1(1)S The Secure Shell Version 2 Enhancements for RSA Keys feature includes a number of additional capabilities to support RSA key-based user authentication for SSH and SSH server host key. Oct 05, 2007 Generating public keys for authentication is the basic and most often used feature of ssh-keygen. Ssh-keygen can generate both RSA and DSA keys. RSA keys have a minimum key length of 768 bits and the default length is 2048. Sep 26, 2019 Generating an SSH key. To generate an SSH key with PuTTYgen, follow these steps: Open the PuTTYgen program. For Type of key to generate, select SSH-2 RSA. Click the Generate button. Move your mouse in the area below the progress bar. When the progress bar is full, PuTTYgen generates your key pair. Type a passphrase in the Key passphrase field.
- October 2, 2015
- Posted by: Syed Shujaat
- Category: Cisco, Networking Solutions
Use this command to generate RSA key pairs for your Cisco device (such as a router). keys are generated in pairs–one public RSA key and one private RSA key.
If your router already has RSA keys when you issue this command, you will be warned and prompted to replace the existing keys with new keys.
NOTE: Before issuing this command, ensure that your router has a hostname and IP domain name configured (with the hostname and ipdomain-name commands).
You will be unable to complete the cryptokeygeneratersacommand without a hostname and IP domain name. (This situation is not true when you generate only a named key pair.)
Here are the steps to Enable SSH and Crypto Key setup : 2 config must requried for SSH
1 Setup Local VTY line User ID and password
router (Config) # Line VTY 0 15
router (Config-line)# login local
router (Config-line)# Exit
!!! create local login ID/Pass
router (Config)# username [loginid] password [cisco]
router (Config)# username loginid1 password cisco1
2. router (Config)# ip domain-name example.com
router (Config)# crypto key generate rsa
how many bits in the modulus [512] :1024
![Ssh generate key pair Ssh generate key pair](/uploads/1/2/6/4/126427168/724624615.png)
router (Config)# ip ssh version2
router (Config)# CTRL Z
Note | Secure Shell (SSH) may generate an additional RSA key pair if you generate a key pair on a router having no RSA keys. The additional key pair is used only by SSH and will have a name such as {router_FQDN }.server. For example, if a router name is “router1.cisco.com,” the key name is “router1.cisco.com.server.” |
This command is not saved in the router configuration; however, the RSA keys generated by this command are saved in the private configuration in NVRAM (which is never displayed to the user or backed up to another device) the next time the configuration is written to NVRAM.
Modulus Length
When you generate RSA keys, you will be prompted to enter a modulus length. The longer the modulus, the stronger the security. However, a longer modules take longer to generate (see the table below for sample times) and takes longer to use.
The size of Key Modulus range from 360 to 2048. Choosing modulus greater than 512 will take longer time.
Router | 360 bits | 512 bits | 1024 bits | 2048 bits (maximum) |
---|---|---|---|---|
Cisco 2500 | 11 seconds | 20 seconds | 4 minutes, 38 seconds | More than 1 hour |
Cisco 4700 | Less than 1 second | 1 second | 4 seconds | 50 seconds |
Cisco IOS software does not support a modulus greater than 4096 bits. A length of less than 512 bits is normally not recommended. In certain situations, the shorter modulus may not function properly with IKE, so we recommend using a minimum modulus of 2048 bits.
Syntax Description : Optional Strings to embed with SSH Crypto key
general-keys | (Optional) Specifies that a general-purpose key pair will be generated, which is the default. | ||
usage-keys | (Optional) Specifies that two RSA special-usage key pairs, one encryption pair and one signature pair, will be generated. | ||
signature | (Optional) Specifies that the RSA public key generated will be a signature special usage key. | ||
encryption | (Optional) Specifies that the RSA public key generated will be an encryption special usage key. | ||
labelkey-label | (Optional) Specifies the name that is used for an RSA key pair when they are being exported.If a key label is not specified, the fully qualified domain name (FQDN) of the router is used. | ||
exportable | (Optional) Specifies that the RSA key pair can be exported to another Cisco device, such as a router. | ||
modulusmodulus-size | (Optional) Specifies the IP size of the key modulus.By default, the modulus of a certification authority (CA) key is 1024 bits. The recommended modulus for a CA key is 2048 bits. The range of a CA key modulus is from 350 to 4096 bits.
| ||
storagedevicename: | (Optional) Specifies the key storage location. The name of the storage device is followed by a colon (:). | ||
redundancy | (Optional) Specifies that the key should be synchronized to the standby CA. | ||
ondevicename: | (Optional) Specifies that the RSA key pair will be created on the specified device, including a Universal Serial Bus (USB) token, local disk, or NVRAM. The name of the device is followed by a colon (:).Keys created on a USB token must be 2048 bits or less. |
Command | Description |
---|---|
copy | Copies any file from a source to a destination, use the copy command in privileged EXEC mode. |
cryptokeystorage | Sets the default storage location for RSA key pairs. |
debugcryptoengine | Displays debug messages about crypto engines. |
hostname | Specifies or modifies the hostname for the network server. |
ipdomain-name | Defines a default domain name to complete unqualified hostnames (names without a dotted-decimal domain name). |
showcryptokeymypubkeyrsa | Displays the RSA public keys of your router. |
show crypto pki certificates | Displays information about your PKI certificate, certification authority, and any registration authority certificates. |
On Windows, you can create SSH keys in many ways. This document explains how to use two SSH applications, PuTTY and Git Bash.
Joyent recommends RSA keys because the node-manta CLI programs work with RSA keys both locally and with the ssh agent. DSA keys will work only if the private key is on the same system as the CLI, and not password-protected.
PuTTY
PuTTY is an SSH client for Windows. You can use PuTTY to generate SSH keys. PuTTY is a free open-source terminal emulator that functions much like the Terminal application in macOS in a Windows environment. This section shows you how to manually generate and upload an SSH key when working with PuTTY in the Windows environment.
About PuTTY
PuTTY is an SSH client for Windows that you will use to generate your SSH keys. You can download PuTTY from www.chiark.greenend.org.uk.
When you install the PuTTY client, you also install the PuTTYgen utility. PuTTYgen is what you will use to generate your SSH key for a Windows VM.
This page gives you basic information about using PuTTY and PuTTYgen to log in to your provisioned machine. For more information on PuTTY, see the PuTTY documentation |
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Generating an SSH key
To generate an SSH key with PuTTYgen, follow these steps:
- Open the PuTTYgen program.
- For Type of key to generate, select SSH-2 RSA.
- Click the Generate button.
- Move your mouse in the area below the progress bar. When the progress bar is full, PuTTYgen generates your key pair.
- Type a passphrase in the Key passphrase field. Type the same passphrase in the Confirm passphrase field. You can use a key without a passphrase, but this is not recommended.
- Click the Save private key button to save the private key. You must save the private key. You will need it to connect to your machine.
- Right-click in the text field labeled Public key for pasting into OpenSSH authorized_keys file and choose Select All.
- Right-click again in the same text field and choose Copy.
Importing your SSH key
Now you must import the copied SSH key to the portal.
- After you copy the SSH key to the clipboard, return to your account page.
- Choose to Import Public Key and paste your SSH key into the Public Key field.
- In the Key Name field, provide a name for the key. Note: although providing a key name is optional, it is a best practice for ease of managing multiple SSH keys.
- Add the key. It will now appear in your table of keys under SSH.
PuTTY and OpenSSH use different formats of public SSH keys. If the text you pasted in the SSH Key starts with
—— BEGIN SSH2 PUBLIC KEY
, it is in the wrong format. Be sure to follow the instructions carefully. Your key should start with ssh-rsa AAAA…
.Once you upload your SSH key to the portal, you can connect to your virtual machine from Windows through a PuTTY session.
Git Bash
The Git installation package comes with SSH. Using Git Bash, which is the Git command line tool, you can generate SSH key pairs. Git Bash has an SSH client that enables you to connect to and interact with Triton containers on Windows.
To install Git:
- (Download and initiate the Git installer](https://git-scm.com/download/win).
- When prompted, accept the default components by clicking Next.
- Choose the default text editor. If you have Notepad++ installed, select Notepad++ and click Next.
- Select to Use Git from the Windows Command Prompt and click Next.
- Select to Use OpenSSL library and click Next.
- Select to Checkout Windows-style, commit Unix-style line endings and click Next.
- Select to Use MinTTY (The default terminal of mYSYS2) and click Next.
- Accept the default extra option configuration by clicking Install.
When the installation completes, you may need to restart Windows.
Launching GitBash
To open Git Bash, we recommend launching the application from the Windows command prompt:
- In Windows, press Start+R to launch the Run dialog.
- Type
C:Program FilesGitbinbash.exe
and press Enter.
Generating SSH keys
First, create the SSH directory and then generate the SSH key pair.
One assumption is that the Windows profile you are using is set up with administrative privileges. Given this, you will be creating the SSH directory at the root of your profile, for example:
- At the Git Bash command line, change into your root directory and type.
- Change into the .ssh directory
C:Usersjoetest.ssh
- To create the keys, type:
- When prompted for a password, type apassword to complete the process. When finished, the output looks similar to:
Uploading an SSH key
To upload the public SSH key to your Triton account:
Ssh2
- Open Triton Service portal, select Account to open the Account Summary page.
- From the SSH section, select Import Public Key.
- Enter a Key Name. Although naming a key is optional, labels are a best practice for managing multiple SSH keys.
- Add your public SSH key.
When Triton finishes the adding or uploading process, the public SSH key appears in the list of SSH keys.
What are my next steps?
Ssh Generate Key Pair
- Adding SSH keys to agent.
- Set up the Triton CLI and CloudAPI on Windows.
- Set up the Triton CLI and CloudAPI.
- Create an instance in the Triton Service Portal.
- Set up the
triton-docker
command line tool. - Visit PuTTYgen to learn more about the PuTTYgen and to seethe complete installation and usage guide.