Datagram Transport Layer Security

Datagram Transport Layer Security (DTLS) is a communications protocol that provides security for datagram-based applications by allowing them to communicate in a way that is designed[1][2] to prevent eavesdropping, tampering, or message forgery. The DTLS protocol is based on the stream-oriented Transport Layer Security (TLS) protocol and is intended to provide similar security guarantees. The DTLS protocol datagram preserves the semantics of the underlying transport—the application does not suffer from the delays associated with stream protocols, but because it uses UDP, the application has to deal with packet reordering, loss of datagram and data larger than the size of a datagram network packet. Because DTLS uses UDP rather than TCP, it avoids the "TCP meltdown problem",[3][4] when being used to create a VPN tunnel.

Not to be confused with TDLS.

Definition

The following documents define DTLS:

• RFC 6347 for use with User Datagram Protocol (UDP),
• RFC 5238 for use with Datagram Congestion Control Protocol (DCCP),
• RFC 5415 for use with Control And Provisioning of Wireless Access Points (CAPWAP),
• RFC 6083 for use with Stream Control Transmission Protocol (SCTP) encapsulation,
• RFC 5764 for use with Secure Real-time Transport Protocol (SRTP) subsequently called DTLS-SRTP in a draft with Secure Real-Time Transport Control Protocol (SRTCP).[5]

DTLS 1.0 is based on TLS 1.1, and DTLS 1.2 is based on TLS 1.2. There is no DTLS 1.1; that version number was skipped in order to harmonize version numbers with TLS.[2]

Implementations

Libraries

Main article: Comparison of TLS implementations § Protocol support

Library support for DTLS

Implementation	DTLS 1.0[1]	DTLS 1.2[2]
Botan	Yes	Yes
cryptlib	No	No
GnuTLS	Yes	Yes
Java Secure Socket Extension	Yes	Yes
LibreSSL	Yes	No
libsystools[6]	Yes	No
MatrixSSL	Yes	Yes
mbed TLS (previously PolarSSL)	Yes[7]	Yes[7]
Network Security Services	Yes[8]	Yes[9]
OpenSSL	Yes	Yes[10]
PyDTLS[11][12]	Yes	Yes
Python3-dtls[13][14]	Yes	Yes
RSA BSAFE	No	No
s2n	No	No
SChannel XP/2003, Vista/2008	No	No
SChannel 7/2008R2, 8/2012, 8.1/2012R2, 10	Yes[15]	No[15]
SChannel 10 (1607), 2016	Yes	Yes[16]
Secure Transport OS X 10.2–10.7 / iOS 1–4	No	No
Secure Transport OS X 10.8–10.10 / iOS 5–8	Yes[17]	No
SharkSSL	No	No
tinydtls [18]	No	Yes
Waher.Security.DTLS [19]	No	Yes
wolfSSL (previously CyaSSL)	Yes	Yes
@nodertc/dtls [20][21]	No	Yes
java-dtls[22]	Yes	Yes
pion/dtls[23] (Go)	No	Yes
californium/scandium[24] (Java)	No	Yes
SNF4J[25] (Java)	Yes	Yes
Implementation	DTLS 1.0	DTLS 1.2

Applications

• Cisco AnyConnect VPN Client uses TLS and DTLS,[26] as do the AnyConnect-compatible open-source OpenConnect client and ocserv server
• Cisco InterCloud Fabric uses DTLS to form a tunnel between private and public/provider compute environments[27]
• F5 Networks Edge VPN Client uses TLS and DTLS[28]
• Citrix Systems NetScaler uses DTLS to secure UDP[29]
• Web browsers: Google Chrome, Opera and Firefox support DTLS-SRTP[30] for WebRTC

Vulnerabilities

In February 2013 two researchers from Royal Holloway, University of London discovered an attack[31] which allowed them to recover plaintext from a DTLS connection using the OpenSSL implementation of DTLS when Cipher Block Chaining mode encryption was used.

See also

• ZRTP
• Reliable User Datagram Protocol
• QUIC

References

1. Rescorla, Eric; Modadugu, Nagendra (April 2006). Datagram Transport Layer Security. doi:10.17487/RFC4347. RFC 4347.
2. Rescorla, Eric; Modadugu, Nagendra (January 2012). Datagram Transport Layer Security Version 1.2. doi:10.17487/RFC6347. RFC 6347.
3. Titz, Olaf (2001-04-23). "Why TCP Over TCP Is A Bad Idea". Retrieved 2015-10-17.
4. Honda, Osamu; Ohsaki, Hiroyuki; Imase, Makoto; Ishizuka, Mika; Murayama, Junichi (October 2005). Atiquzzaman, Mohammed; Balandin, Sergey I (eds.). "Performance, Quality of Service, and Control of Next-Generation Communication and Sensor Networks III". 6011: 60110H. Bibcode:2005SPIE.6011..138H. CiteSeerX 10.1.1.78.5815. doi:10.1117/12.630496. Cite journal requires |journal= (help); |chapter= ignored (help)
5. Peck, M.; Igoe, K. (2012-09-25). "Suite B Profile for Datagram Transport Layer Security / Secure Real-time Transport Protocol (DTLS-SRTP)". IETF.
6. Julien Kauffmann. "libsystools: A TLS/DTLS open source library for Windows/Linux using OpenSSL". Sourceforge.
7. "mbed TLS 2.0.0 released". ARM. 2015-07-13. Retrieved 2015-08-25.
8. "NSS 3.14 release notes". Mozilla Developer Network. Mozilla. Retrieved 2012-10-27.
9. "NSS 3.16.2 release notes". Mozilla Developer Network. Mozilla. 2014-06-30. Retrieved 2014-06-30.
10. "As of version 1.0.2". The OpenSSL Project. The OpenSSL Project. 2015-01-22. Retrieved 2015-01-26.
11. Ray Brown. "pydtls - Datagram Transport Layer Security for Python". GitHub.
12. Ray Brown. "DTLS for Python". Python Software Foundation.
13. Ray Brown/Mobius Software LTD. "pydtls - Datagram Transport Layer Security for Python". GitHub.
14. Ray Brown/Mobius Software LTD. "DTLS for Python3 Based on PyDTLS". Python Software Foundation.
15. "An update is available that adds support for DTLS in Windows 7 SP1 and Windows Server 2008 R2 SP1". Microsoft. Retrieved 13 November 2012.
16. Justinha. "TLS (Schannel SSP) changes in Windows 10 and Windows Server 2016". docs.microsoft.com. Retrieved 2017-09-01.
17. "Technical Note TN2287: iOS 5 and TLS 1.2 Interoperability Issues". iOS Developer Library. Apple Inc. Retrieved 2012-05-03.
18. Olaf Bergmann. "tinydtls". Eclipse Foundation.
19. Peter Waher. "Waher.Security.DTLS". Waher Data AB.
20. Dmitriy Tsvettsikh. "Secure UDP communications using DTLS in pure js". GitHub.
21. Dmitriy Tsvettsikh. "DTLS in pure js". npm.
22. Mobius Software LTD. "Non blocking Java DTLS Implementation based on BouncyCastle and Netty". Mobius Software LTD.
23. Sean DuBois. "pion/dtls: DTLS 1.2 Server/Client implementation for Go". GitHub.
24. "californium/scandium: DTLS 1.2 Server/Client implementation for java and coap. Includes connection id extension". Eclipse Foundation.
25. SNF4J.ORG. "Simple Network Framework for Java (SNF4J)". GitHub.
26. "AnyConnect FAQ: tunnels, reconnect behavior, and the inactivity timer". Cisco. Retrieved 26 February 2017.
27. "Cisco InterCloud Architectural Overview" (PDF). Cisco Systems.
28. "f5 Datagram Transport Layer Security (DTLS)". f5 Networks.
29. "Configuring a DTLS Virtual Server". Citrix Systems.
30. "WebRTC Interop Notes". Archived from the original on 2013-05-11.
31. Plaintext-Recovery Attacks Against Datagram TLS

External links

• "Transport Layer Security (tls) - Charter". IETF.
• Modadugu, Nagendra; Rescorla, Eric (2003-11-21). "The Design and Implementation of Datagram TLS" (PDF). Stanford Crypto Group. Retrieved 2013-03-17.
• AlFardan, Nadhem J.; Paterson, Kenneth G. "Plaintext-Recovery Attacks Against Datagram TLS" (PDF). Retrieved 2013-11-25.
• Gibson, Steve; Laporte, Leo (2012-11-28). "Datagram Transport Layer Security". Security Now 380. Retrieved 2013-03-17. Skip to 1:07:14.
• Robin Seggelmann's Sample Code: echo, character generator, and discard client/servers.

This article is based on material taken from the Free On-line Dictionary of Computing prior to 1 November 2008 and incorporated under the "relicensing" terms of the GFDL, version 1.3 or later.