We are working on SNS to HTTPS API integration between 2 teams. So, another team has SNS topic configured in `us-east-1` region and our HTTPS API is running in `us-west-2` region. 

Just wanted to check if we can process SNS messages generated from `us-east-1` and a **different AWS account** in `us-west-2` region.

I read somewhere (can't remember the blog post link now), that if SNS messages are generated in `us-east-1`, they have to be processed in `us-east-1` only. If we try to process in `us-east-2`, message signature verification will fail and throws an invalid TopicArn exception.

Please guide if this is correct.