DTLS Protocol Features | CCIE Security Exam | Cisco

DTLS Protocol Features

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Which three features describe DTLS protocol? (Choose three.)



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A. B. C. D. E. F.


DTLS (Datagram Transport Layer Security) is a protocol that provides security for datagram-based applications, such as UDP. It is similar to TLS (Transport Layer Security), but it is designed to work over an unreliable datagram transport. Here are the three features that describe DTLS protocol:

B. DTLS provides enhanced security, as compared to TLS: DTLS provides the same level of security as TLS, but it adds some extra features to address the challenges of working over an unreliable datagram transport. For example, DTLS uses a sequence number to detect and discard duplicate packets, and it uses a cookie mechanism to prevent denial-of-service attacks.

D. DTLS is designed to prevent man-in-the-middle attacks, message tampering, and message forgery: Like TLS, DTLS provides authentication, confidentiality, and integrity services. DTLS uses a public-key infrastructure (PKI) to authenticate peers, and it uses block cipher encryption and message authentication code (MAC) to provide confidentiality and integrity services.

E. DTLS is used by application layer protocols that use UDP as a transport mechanism: DTLS is commonly used by applications that use UDP as a transport protocol, such as Real-time Transport Protocol (RTP) and Datagram Congestion Control Protocol (DCCP). These protocols require low-latency, loss-tolerant transport, which makes them unsuitable for TCP. DTLS allows these protocols to use a secure transport without sacrificing their performance requirements.

A. DTLS handshake does not support reordering or manage loss packets: This statement is incorrect. DTLS uses a handshake protocol that is similar to the TLS handshake protocol. During the handshake, the peers exchange messages to establish a shared secret key that will be used to encrypt and authenticate datagrams. The handshake protocol is designed to handle reordering and lost packets.

C. DTLS provides block cipher encryption and decryption services: This statement is partially correct. DTLS provides encryption and decryption services, but it does not mandate the use of a specific encryption algorithm. Instead, it allows the application to select an appropriate algorithm based on its security and performance requirements.

F. DTLS does not support replay detection: This statement is incorrect. DTLS provides a replay protection mechanism to prevent an attacker from replaying old messages to the peer. The replay protection mechanism is based on the sequence number, which is included in each message. The receiver maintains a window of acceptable sequence numbers and discards any message that falls outside this window.