Your browser does not allow storing cookies. We recommend enabling them.


Host Key

Enabling Elliptic Curve Host Keys

Add the ECDSA host-key algorithms (remove any key sizes you do not wish to allow) within the <connection> section of your ssh-server-config.xml:

<hostkey-algorithm name="ecdsa-sha2-nistp256" />
<hostkey-algorithm name="ecdsa-sha2-nistp384" />
<hostkey-algorithm name="ecdsa-sha2-nistp521" />
<hostkey-algorithm name="ssh-dss" />
<hostkey-algorithm name="ssh-rsa" />
<hostkey-algorithm name="" />
<hostkey-algorithm name="" />
<hostkey-algorithm name="x509v3-sign-dss" />
<hostkey-algorithm name="x509v3-sign-rsa" />
<hostkey-algorithm name="" />
<hostkey-algorithm name="" />

To enable ECDSA host keys for X.509, add also the following hostkey-algorithm names: x509v3-ecdsa-sha2-nistp256, x509v3-ecdsa-sha2-nistp384, x509v3-ecdsa-sha2-nistp521.

Once the configuration has been amended to use the ECDSA host-key algorithms you can create the ECDSA host key.

Creating ECDSA Host Key

Create the ECDSA host key using ssh-keygen-g3. For more information on ssh-keygen-g3, refer to the Tectia Server Administrator Manual.


You must ensure your SSH client can accept an ECDSA host key.

The following command will add an ECDSA host key to your SSH Server. By default, a 256-bit key is generated. (The -b option can be used to define the size of the key.)

Using ssh-keygen-g3 with –t (type), –H (host key) and –P (no passphrase):

[root@host ~]# ssh-keygen-g3 -t ecdsa -H -P
Generating 256 bits ECDSA key on nistp256 curve

Key generated.
256-bit ecdsa,, Wed Aug 26 2015 10:00:00 +0100
Private key saved to /etc/ssh2/hostkey
Public key saved to /etc/ssh2/

After you have made the changes, you must stop and start the server to take the new configuration into use:

# /etc/init.d/ssh-server-g3 stop
# /etc/init.d/ssh-server-g3 start


Highlights from the SSH.COM blog:

  • Cryptomining with the SSH protocol: what big enterprises need to know about it

    Cryptomining malware is primarily thought of as targeting desktops and laptops and is used to hijack system resources to mine cryptocurrency.
    Read more
  • SLAM the door shut on traditional privileged access management

    Did you know that something as trivial-sounding as granting access for your developers or third parties to a product development environment can throw a gorilla-sized monkey wrench into your operations and productivity?
    Read more
  • We broke the IT security perimeter

    Everyone understands the concept of a security perimeter. You only gain access if you are identified and authorized to do so.
    Read more