ADFS RADIUS Authentication Provider v1.1

The Authentication Provider I wrote for ADFS to make use of RADIUS (for use with something like SAFENET) has been updated to v1.1.

Changes include the NL localisation and support for differing claim types. Thanks to Dave Liefbroer for his work on these bits.

Custom identify claims make use of the IdentityClaims registry key, which will default to ttp:// for User PrincipalNames. samAccountName etc can be used.

Updated binaries are available, but please do build this yourself.

Download: ADFS Authentication Adapter v1.1


Active Directory Federation Services, AD-FS, is the de facto identity provider in a Microsoft environment. Many organizations will be using it to authenticate Office 365 users to an on-premise Active Directory. Support amongst cloud service providers is growing, allowing you to authenticate not just O365 users but users of a variety of business applications.

In certain circumstances, you may want to require multi-factor authentication (MFA). Out the box, AD-FS only provides support for X.509 certificates. Thankfully there’s the concept of Authentication Adapters, allowing you to develop your own MFA plug-in. I’ve developed a quick RADIUS plugin that allows you to prompt users to enter a one-time PIN and send the response to a RADIUS server, along with the accounts userPrincipalName, for validation.

RADIUS Authentication Adapter

The software is open-source and licensed under the GPL and relies on the excellent Radius.Net library.


I strongly recommend compiling your own version rather than downloading a DLL and installing it into your AD FS servers. If you’re comfortable with the risks of that, you can download it from the links below.

Download Sourcecode (C#, 4.5)
Download Binaries (Version 1.0).


The below instructions cover installation into AD FS and make no attempt to document any RADIUS/NPS configuration.

  1. Extract the zip file to a convenient location and open install.ps1 in your favorite editor;
  2. Ammend the variables in install.ps1 to match your RADIUS server, shared key and any ports needed;
  3. From an elevated PowerShell prompt, run install.ps1
  4. Restart the AD FS service to complete registration
  5. If you have multiple AD FS servers in your farm, repeat the process on each but press CTRL-C when promtped to register the authentication adapter

Extract private key from Cisco private-config

This blog post discusses extracting a private key from Cisco IOS’s private-config file. I recently generated a keypair on an IOS router and had forgot to flag it as “exportable”, making it difficult to backup. As the key-pair was used for IPSec authentication it was an important key to backup.

The first step is to recover private-config from the device, which I’m not going to cover in this post. Opening the file in a text editor, locate the section that begins “crypto RSA-key-pair” and save the hexadecimal values to a text file, the section will look like this:

crypto RSA-key-pair MyKey 0 1440004978
308204BC 02010030 0D06092A 864886F7 0D010101 05000482 04A63082 04A20201
00028201 0100DE8D 63241465 57356A77 57FC2C3D BBDD8454 F25B6B1A DB487C6D
AA0C1157 F665AF18 08EFC785 C23D3185 06F3D51A 42C94F06 5A97756A C83693C6

When saving to a text file, omit the section beginning “crypto RSA-key-pair”, only the hexadecimal values are required.
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