Scenario: – I have a widows desktop application that need to upload images for every x minutes.

My Approach:
– I have created an IAM User with only access to
GetAccessKeyLastUsed
CreateAccessKey
UpdateAccessKey
ListAccessKeys

– In my backend with user having these permission i will handling the keys like this
– My wpf at regular interval makes call to my backend and expires the existing access key and creates a new one and deactivates old one and delete old one and sends the new access key and secret id this is to make sure that even if some one gets the creds they wont be able to damage for long time
– I have restricted that user’s permission with these secret key and access id to only upload the object into S3

Problem:
– Is it safe to send the secret key and access id from the backend to wpf application. I cannot use presigned urls as i will be sending 1000’s of images from my windows application to s3 and generating presigned url for each image might cause overhead(in my opinion) . Is there any better way to do this

Please suggest a secure way to connect end to end