1. Introduction ....................................................4
1.1. Requirements Terminology ...................................5
2. Usage Model .....................................................5
3. Overview of DTLS ................................................5
3.1. Loss-Insensitive Messaging .................................6
3.2. Providing Reliability for Handshake ........................6
3.2.1. Packet Loss .........................................6
3.2.2. Reordering ..........................................7
3.2.3. Message Size ........................................7
3.3. Replay Detection ...........................................7
4. Differences from TLS ............................................7
4.1. Record Layer ...............................................8
4.1.1. Transport Layer Mapping ............................10
4.1.1.1. PMTU Issues ...............................10
4.1.2. Record Payload Protection ..........................12
4.1.2.1. MAC .......................................12
4.1.2.2. Null or Standard Stream Cipher ............13
4.1.2.3. Block Cipher ..............................13
4.1.2.4. AEAD Ciphers ..............................13
4.1.2.5. New Cipher Suites .........................13
4.1.2.6. Anti-Replay ...............................13
4.1.2.7. Handling Invalid Records ..................14
4.2. The DTLS Handshake Protocol ...............................14
4.2.1. Denial-of-Service Countermeasures ..................15
4.2.2. Handshake Message Format ...........................18
4.2.3. Handshake Message Fragmentation and Reassembly .....19
4.2.4. Timeout and Retransmission .........................20
4.2.4.1. Timer Values ..............................24
4.2.5. ChangeCipherSpec ...................................25
4.2.6. CertificateVerify and Finished Messages ............25
4.2.7. Alert Messages .....................................25
4.2.8. Establishing New Associations with Existing
Parameters .........................................25
4.3. Summary of New Syntax .....................................26
4.3.1. Record Layer .......................................26
4.3.2. Handshake Protocol .................................27
5. Security Considerations ........................................27
6. Acknowledgments ................................................28
7. IANA Considerations ............................................28
8. Changes since DTLS 1.0 .........................................29
9. References .....................................................30
9.1. Normative References ......................................30
9.2. Informative References ....................................31
1. Introduction ....................................................4
1.1. Requirements Terminology ...................................5
2. Usage Model .....................................................5
3. Overview of DTLS ................................................5
3.1. Loss-Insensitive Messaging .................................6
3.2. Providing Reliability for Handshake ........................6
3.2.1. Packet Loss .........................................6
3.2.2. Reordering ..........................................7
3.2.3. Message Size ........................................7
3.3. Replay Detection ...........................................7
4. Differences from TLS ............................................7
4.1. Record Layer ...............................................8
4.1.1. Transport Layer Mapping ............................10
4.1.1.1. PMTU Issues ...............................10
4.1.2. Record Payload Protection ..........................12
4.1.2.1. MAC .......................................12
4.1.2.2. Null or Standard Stream Cipher ............13
4.1.2.3. Block Cipher ..............................13
4.1.2.4. AEAD Ciphers ..............................13
4.1.2.5. New Cipher Suites .........................13
4.1.2.6. Anti-Replay ...............................13
4.1.2.7. Handling Invalid Records ..................14
4.2. The DTLS Handshake Protocol ...............................14
4.2.1. Denial-of-Service Countermeasures ..................15
4.2.2. Handshake Message Format ...........................18
4.2.3. Handshake Message Fragmentation and Reassembly .....19
4.2.4. Timeout and Retransmission .........................20
4.2.4.1. Timer Values ..............................24
4.2.5. ChangeCipherSpec ...................................25
4.2.6. CertificateVerify and Finished Messages ............25
