TLS vs DTLS

Both TLS (Transport Layer Security) and DTLS (Datagram Transport Layer Security) provide encryption and security for network communication, but they are designed for different transport protocols.

Feature	TLS (Transport Layer Security)	DTLS (Datagram Transport Layer Security)
Protocol Type	Reliable (TCP-based)	Unreliable (UDP-based)
Transport Layer	Works over TCP	Works over UDP
Reliability	Uses TCP for error correction and retransmission	Uses UDP, adds its own mechanisms for handling packet loss
Latency	Higher due to TCP's retransmission and ordering	Lower because it avoids TCP overhead
Use Cases	Web browsing (HTTPS), Email (IMAP/POP3 over TLS), VoIP over TCP	VoIP, Video Streaming, Online Gaming, VPN (DTLS for OpenVPN, Cisco AnyConnect)
Security	Provides strong encryption and authentication	Provides similar security but with extra protection against packet loss/reordering
Packet Loss Handling	TCP handles retransmission automatically	Uses sequence numbers and retransmission timers to handle dropped packets
Order of Messages	Enforces strict ordering (packets must arrive in sequence)	Does not strictly enforce order, making it better for real-time applications
Overhead	Higher (due to TCP's acknowledgment and retransmission)	Lower (UDP has no built-in retransmission overhead)
Handshake Speed	Slower (requires multiple round trips)	Faster (reduces round trips, optimized for real-time)
Best for	Secure web communication, email security, financial transactions	Secure real-time apps, low-latency VoIP/video, gaming, VPN