Signature Does Not Match Error when sending to S3 from an AWS IoT client.

I'm working on an embedded device that will send logs to an S3 bucket. It uses an MQTT client to publish a link request and receive a generated URL on a subscribed topic. It then uses the URL to upload a log file to S3. My code base is the AWS embedded C SDK.

The code successfully connects to the AWS endpoint to request and receive the URL. It then uses libcurl to upload the file with HTTPS.

When the code attempts to upload the file to S3, the it gets back a 403 error with this message: "The request signature we calculated does not match the signature you provided. Check your key and signing method."

I'm confused since those keys were used for the AWS IoT request with no issues.

I searched online for this error but nothing I saw applied to this use case. Has anybody else had a similar issue where device keys work for the AWS IoT side but not the S3 side?

Thanks in advance for help on this.

SOLVED

Bit by the newline in the MD5 file. Used a different utility and got through.

Edited by: GaryKB on Aug 19, 2020 5:19 AM