I need help for my bachelor thesis. I have a general question regarding hybrid encryption in different ransomware. The hybrid encryption often uses symmetric and asymmetric encryption techniques.
During an infection the symmetric key will be generated on the system. This symmetric key will be encrypted with the public key of the asymmetric key pair. The public key can be hardcoded in the source code of the ransomware. Now I read an article that says this is an bad approach, because if one victim will pay the ransom he can share the private key. That is right, but is it possible that the victim send me his encrypted symmetric key and I will send the decrypted key back?
Have I overlook something?
I hope someone could help me to clarify this understanding problem.