RPost RMail Email Encryption is an email security service that encrypts sensitive email messages and attachments for security and regulatory compliance purposes. The service automatically detects and selects the optimal encryption delivery method for each recipient to provide the simplest user experience without requiring registration or link retrieval. The product supports multiple encryption approaches including secure Transmission Encryption and Message Level Encryption with AES 256-bit encrypted PDF. It includes dynamic encryption that attempts secure transmission first and reverts to message-level encryption if security requirements are not met. The service provides outbox-to-inbox protection with configurable password delivery options. RMail includes predictive technologies that automatically encrypt messages based on content or structure, and adapts transmission methods based on message size thresholds. Recipients receive a one-click encrypted reply option that allows them to respond and upload up to 200 MB of attachments using the same encryption method. Each encrypted message generates a Registered Receipt email record that serves as auditable proof of privacy compliance for regulations including GDPR and HIPAA. The service offers various encryption methods, policy rules, compliance tracking, delivery tracking, and branding options. Developers can integrate RMail encryption services into applications using email routing rules or the REST API, and retrieve message delivery status and proof records through the same methods.