Cross-Account S3 Access Still Fails. Just Open It Up?
A partner account still gets AccessDenied on your encrypted S3 objects after you added a bucket policy. A teammate wants to make the bucket and key public. Defend the right fix.
the decision you defend
You granted a partner account access to your S3 bucket with a bucket policy, but their role still gets AccessDenied reading the objects, which are encrypted with a customer-managed KMS key. A teammate says just make the bucket public and let the key allow everyone. What do you do?
the situation
A partner in another AWS account needs to read objects from one of your S3 buckets. You added a bucket policy that allows their role, but their requests still come back as AccessDenied.
context
The objects are encrypted with a customer-managed KMS key in your account. The partner role has IAM permissions on their side to call S3. Nobody has touched the KMS key policy. A teammate, frustrated after trying bucket policy tweaks, suggests turning off Block Public Access, making the bucket public, and setting the KMS key policy to allow all principals so the partner can finally read the data.
How this challenge works
Take a position on the decision above and defend it. A senior-engineer AI will push back over up to 5 rounds. When you are done, you are scored against a verified rubric so you can see exactly what a complete answer covers - these are learning prompts, not gotchas.