if credElements[2] != string(stype) {
		if stype == serviceSTS {
			return ch, ErrInvalidServiceSTS
		}
		return ch, ErrInvalidServiceS3
	}
	cred.scope.service = credElements[2]
	if credElements[3] != "aws4_request" {
		return ch, ErrInvalidRequestVersion
	}
	cred.scope.request = credElements[3]
	return cred, ErrNone
}

// Parse signature from signature tag.

    "account": "minio",
    "groups": null,
    "action": "s3:ListBucket",
    "bucket": "test",
    "conditions": {
      "Authorization": [
        "AWS4-HMAC-SHA256 Credential=minio/20220507/us-east-1/s3/aws4_request, SignedHeaders=host;x-amz-content-sha256;x-amz-date, Signature=62012db6c47d697620cf6c68f0f45f6e34894589a53ab1faf6dc94338468c78a"
      ],
      "CurrentTime": [
        "2022-05-07T18:31:41Z"
      ],
      "Delimiter": [

```
curl -v $(go run presigned.go)
...
...
> GET /functionbucket/testobject?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=minioadmin%2F20230205%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20230205T173023Z&X-Amz-Expires=1000&X-Amz-SignedHeaders=host&lambdaArn=arn%3Aminio%3As3-object-lambda%3A%3Atoupper%3Awebhook&X-Amz-Signature=d7e343f0da9d4fa2bc822c12ad2f54300ff16796a1edaa6d31f1313c8e94d5b2 HTTP/1.1