ecsgo doesn't appear to support KMS encrypted sessions, so I changed the command to use aws cli instead.
✗ ecsgo
? Select a task:
Cluster: redacted | Service: api | Task: 12345308b064a4a911c205c63e0bbbf
Connecting to container redactedi
Starting session with SessionId: ecs-execute-command-12345
SessionId: ecs-execute-command-12345 :
----------ERROR-------
Encountered error while initiating handshake. Fetching data key failed: Unable to retrieve data key, Error when decrypting data key InvalidCiphertextException:```
As per https://github.com/tedsmitt/ecsgo/pull/11: