Any type of Ardor blockchain transaction can optionally have a message attachment. It can be text or binary, plain or encrypted. Messages can be used to indicate the purpose of the transaction, referring to an invoice or account number, or just contain any information useful for the sender or recipient. When a message is sent encrypted, a unique encryption key is used for every new message, allowing its content to be safely revealed to a third party if needed.
Messaging is a feature on the public blockchain Ignis and available to all child chains on the Ardor Platform