This advisory addresses an issue when a DynamoDB Set attribute is marked as SIGN_ONLY in the AWS Database Encryption SDK (DB-ESDK) for DynamoDB. This also includes when a Set is part of a List or a Map. DB-ESDK for DynamoDB supports "SIGN_ONLY" and "ENCRYPT_AND_SIGN" attribute actions. In version 3.1.0 and below, when a Set type is assigned a "SIGN_ONLY" attribute action, there is a chance that signature validation of the record containing a Set will fail on read, even if the Set attributes contain the same values. The probability of a failure depends on the order of the elements in the Set combined with how DynamoDB returns this data, which is undefined. This update addresses the issue by ensuring that any Set values are canonicalized in the same order while written to DynamoDB as when read back from DynamoDB.