We consider certificate generation with CA-generated keys. Assume the second transmission of (CertA, kpr,A) takes place over an authenticated but insecure channel, i.e., Oscar can read this message.
1. Show how he can decrypt traffic which is encrypted by means of a Diffie- Hellman key that Alice and Bob generated.
2. Can he also impersonate Alice such that he computes a DH key with Bob without Bob noticing?