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Solved: How do I decrypt SSL/TLS traffic using a Windows machine?

This article describes how to decrypt SSL/TLS traffic using a Windows machine.

Solution

Step 1: Go to This PC, right-click on an empty space then select Properties from the context menu.

Go to This PC, right-click on an empty space then select Properties.

Step 2: Click on the Advanced system settings link on the left side.

Click on the Advanced system settings link on the left side.

Step 3: Click on the Environment Variables button.

Click on the Environment Variables button.

Step 4: Click on the New button.

Step 5: Type SSLKEYLOGFILE in the Variable name field.

Step 6: For Variable value, click on the Browse File button and choose the file where to save the TLS/SSL keys. In this example, tlskey.txt has been created.

Click on the New button. Type SSLKEYLOGFILE in the Variable name field. For Variable value, click on the Browse File button and choose the file where to save the TLS/SSL keys. In this example, tlskey.txt has been created.

Step 7: Click on the OK button until all recent window prompts have been closed.

Step 8: Start capture and enable filters in GUI > Network > Packet Capture.

Step 9: Generate TLS/SSL traffic then download the capture and open it on Wireshark.

Step 10: After opening the capture on Wireshark, go to Edit > Preferences.

After opening the capture on Wireshark, go to Edit > Preferences.

Step 11: Under Protocols, check and then select TLS (Transport Layer Security).

Step 12: Under (Pre)-Master-Secret log filename, click on the Browse button then choose the TLS key file.

Step 13: Click on the OK button.

Under (Pre)-Master-Secret log filename, click on the Browse button then choose the TLS key file. Click on the OK button.

Step 14: Decryption of TLS/SSL traffic is completed now.

Decryption of TLS/SSL traffic is completed now.

Alex Lim is a certified IT Technical Support Architect with over 15 years of experience in designing, implementing, and troubleshooting complex IT systems and networks. He has worked for leading IT companies, such as Microsoft, IBM, and Cisco, providing technical support and solutions to clients across various industries and sectors. Alex has a bachelor’s degree in computer science from the National University of Singapore and a master’s degree in information security from the Massachusetts Institute of Technology. He is also the author of several best-selling books on IT technical support, such as The IT Technical Support Handbook and Troubleshooting IT Systems and Networks. Alex lives in Bandar, Johore, Malaysia with his wife and two chilrdren. You can reach him at [email protected] or follow him on Website | Twitter | Facebook

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