Disabling RC4 - SSL Certificates - Namecheap.com (2024)

Deactivating RC4 on IIS

RC4 is a stream cipher for bulk encryption that nowadays is considered as practically vulnerable and was officially deprecated by Internet Engineering Task Force.

1. Open registry editor:

   Win + R >> regedit

   See Also

   How to Disable Weak Ciphers in Dell Security Management Server and Virtual ServerHow to disable 3DES and RC4 on Windows Server 2019? - Microsoft Q&ALesson learned: Disabling weak TLS cipher suites without breaking up everything • Soluto Engineering BlogDisable-TlsCipherSuite (TLS)

2. Navigate to:

   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\Schannel\Ciphers

3. Right-click on Ciphers >> New >> Key

   

   See Also

   Apache Disabling SSL v3 Instructions

   Name the key 'RC4 40/128'

4. Right-click on RC4 40/128 >> New >> DWORD (32-bit) Value

   

   Name the value 'Enabled'

5. Double-click the created Enabled value and make sure that there is zero (0) in Value Data: field >> click OK

   

6. Create two more keys with the names 'RC4 56/128' and 'RC4 128/128' in the Ciphers directory. Repeat steps 4 and 5 for each of them.
7. After step 6 is completed, you should have three keys for RC4 in total in Ciphers. Each RC4 key should have the DWORD value named 'Enabled' with zero (0) value data.

   

8. You may need to restart Windows Server to apply the changes.