To ensure confidentiality and security when working with accounting services, law firms should establish clear protocols and policies regarding data protection and privacy. This may include requiring the accounting services provider to sign a non-disclosure agreement (NDA) and implementing secure communication channels, such as encrypted email or secure file transfer. Law firms should also consider the physical security of their financial records and ensure that only authorized personnel have access to them. Additionally, it is important to choose accounting services providers with a proven record of accomplishment of confidentiality and data security, and to regularly review and assess their security measures.