DPAPI fails with CryptographicException when trying to decrypt Chrome cookies

Question

i am trying to get session from my Chrome browser. i can see 2 cookie files in Developer Tools. but this is inconvenient for the user to get cookie values from browser, i wo

Answer 1

I finally figured it out. according to Chromium sources, two methods are used to decrypt the cookie value.

1. if the cookie value starts with v10 chars, we use AES_256_GCM
2. otherwise, DPAPI is used

for the first method we need key and nonce. key is located in Google Chrome files and nonce is located in encrypted cookie value.

it remains unclear for me - what determines which method is used