Invalid base64: “hello”

Hello,

as part of the lab, I entered the following command:

C:Users****>aws kms encrypt –plaintext "hello" –key-id arn:aws:kms:us-east-1:373903563980:key/09a19e14-f463-4601-bd89-f9a95f138171

Invalid base64: "hello"

this was after running the aws configure command and entering in the access key ID and client secret in the aws configure command.

can you tell me if there is something i’m doing wrong?  is cloud_user given sufficient access to create kms keys via the cli?  I was able to create keys via the portal.

thank  you