What is the default encryption method for both of the IKE phases when configuring a VPN on the firewall?

The default encryption method for both phases of IKE (Internet Key Exchange) when configuring a VPN on a SonicWall firewall is AES 128. This choice is considered standard because AES (Advanced Encryption Standard) provides a good balance between security and performance. AES is widely recognized for its robustness against various attacks and is a modern encryption method that has become the preferred choice for secure communications.

Specifically, while SHA (Secure Hash Algorithm) options like SHA-1 or SHA-256 are often utilized for hashing in the IKE process, they are not encryption methods. Thus, while they might play a role in the overall security context, they do not fulfill the role of the encryption standard stipulated in the question.

AES 128, in particular, is favored due to its efficiency in processing and the adequate level of security it provides, making it suitable for a variety of applications within VPN technology. This choice reflects the best practices in network security when establishing secure connections over potentially insecure channels.