If you want just to obtain public key from PFK file then directly go to the command lines far below.

Public key is used by unit test to access internal classes or properties from other assembly. The assembly to be accessed must add the following code in project AssemblyInfo.cs file:

[assembly: InternalsVisibleTo("VideoBrowser.Test, PublicKey=00240000048000009400000006020000002400005253413100040000010001003d454c10e8118a" +
    "f6e3ae8b517e05c1ad188b072aafdd4b131e3984e5fca8ebda5793ef5aac6a16d210883d806f2d" +
    "23c27a01896da983941821c6d639be111795ff4ea57f2de9bd5790a52554cba2bcc9446d53e55d" +
    "696f5e37904f79e6750dac1a0676a1cf2a73f7ea9c0418f1bca7fabc1be09df2fdd283b58f8539" +
    "8a79f8b1")]

VideoBrowser.Test is the name of the unit test or other project which want an access for this project or assembly like the unit test.
PublicKey is the public key of the project to be accessed, it is in the SNK file, but sometime we get PFX key instead from Visual Studio.
Therefore we must obtain the public key from PFK file by:

  1. Converting PFK file it to snk.
  2. Get public key from snk file by producing txt file from snk

Command Lines

You can use full path of sn.exe or set the path of sn.exe in your Path of System Environment Variable Path in Window settings.
In my computer it is installed by Visual Studio in: C:\Program Files (x86)\Microsoft SDKs\Windows\v10.0A\bin\NETFX 4.7.2 Tools\x64.
In this example, the PFX file name is key.pfx.

Convert PFX to SNK file

sn.exe -i  key.pfx Personal

The following question will appear:

Microsoft (R) .NET Framework Strong Name Utility Version 4.0.30319.0
Copyright (c) Microsoft Corporation. All rights reserved.

Enter the password for the PKCS#12 key file:

Enter the PFX password which is given when you created it.
If correct then will show a message: Key pair installed into ‘Personal’.

Type the following code to producekey. snk file.

sn.exe -pc Personal key.snk

Microsoft (R) .NET Framework Strong Name Utility Version 4.0.30319.0 Copyright (c) Microsoft Corporation. All rights reserved.

Public key written to key.snk

A key.snk file will be created.

Show or extract the public key of key.snk file to a file text key.txt

sn.exe -tp key.snk > key.txt

or the following to show the public key without creating a text file.

sn.exe -tp key.snk

The key.txt contains public key token:

Microsoft (R) .NET Framework Strong Name Utility Version 4.0.30319.0 Copyright (c) Microsoft Corporation. All rights reserved.

Public key (hash algorithm: sha1): 00240000048000009400000006020000002400005253413100040000010001003d454c10e8118a f6e3ae8b517e05c1ad188b072aafdd4b131e3984e5fca8ebda5793ef5aac6a16d210883d806f2d 23c27a01896da983941821c6d639be111795ff4ea57f2de9bd5790a52554cba2bcc9446d53e55d 696f5e37904f79e6750dac1a0676a1cf2a73f7ea9c0418f1bca7fabc1be09df2fdd283b58f8539 8a79f8b1

Public key token is 52664285ede97425

And we can put the Public key, but not the public key token in the InternalsVisibleTo command like above.
After recompiling VideoBrowser and VideoBrowser.Test then VideoBrowser.Test project classes can access internal member of VideoBrowser.