The former combined with the authentication aspect enables the latter.
1. plain-text code gets loaded into enclave
2. enclave generates a keypair
3. enclave authenticates itself against a 3rd party (the DRM/malware mothership) and sends it the pubkey
4. mothership sends additional secrets / code, only decryptable by the enclave
5. you now have uninspectable code running on your machine
And since the enclave can persist itself with the sealing key the handshake only has to happen once, e.g. during the installation phase which often happens with elevated privileges, i.e. also includes network access.
Oh, and the enclave also has access to the rest of the process memory, i.e. the system is not shielded from the actions of said uninspectable code.
1. plain-text code gets loaded into enclave
2. enclave generates a keypair
3. enclave authenticates itself against a 3rd party (the DRM/malware mothership) and sends it the pubkey
4. mothership sends additional secrets / code, only decryptable by the enclave
5. you now have uninspectable code running on your machine
And since the enclave can persist itself with the sealing key the handshake only has to happen once, e.g. during the installation phase which often happens with elevated privileges, i.e. also includes network access.
Oh, and the enclave also has access to the rest of the process memory, i.e. the system is not shielded from the actions of said uninspectable code.