RFC 6347 - 4.3. Summary of New Syntax

4.3. Summary of New Syntax

This section includes specifications for the data structures that have changed between TLS 1.2 and DTLS 1.2. See [TLS12] for the definition of this syntax.

4.3.1. Record Layer

struct {
     ContentType type;
     ProtocolVersion version;
     uint16 epoch;                                     // New field
     uint48 sequence_number;                           // New field
     uint16 length;
     opaque fragment[DTLSPlaintext.length];
   } DTLSPlaintext;

   struct {
     ContentType type;
     ProtocolVersion version;
     uint16 epoch;                                     // New field
     uint48 sequence_number;                           // New field
     uint16 length;
     opaque fragment[DTLSCompressed.length];
   } DTLSCompressed;

   struct {
     ContentType type;
     ProtocolVersion version;
     uint16 epoch;                                     // New field
     uint48 sequence_number;                           // New field
     uint16 length;
     select (CipherSpec.cipher_type) {
       case block:  GenericBlockCipher;
       case aead:   GenericAEADCipher;                 // New field
     } fragment;
   } DTLSCiphertext;

4.3.2. Handshake Protocol

enum {
  hello_request(0), client_hello(1), server_hello(2),
  hello_verify_request(3),                          // New field
  certificate(11), server_key_exchange (12),
  certificate_request(13), server_hello_done(14),
  certificate_verify(15), client_key_exchange(16),
  finished(20), (255) } HandshakeType;

struct {
  HandshakeType msg_type;
  uint24 length;
  uint16 message_seq;                               // New field
  uint24 fragment_offset;                           // New field
  uint24 fragment_length;                           // New field
  select (HandshakeType) {
    case hello_request: HelloRequest;
    case client_hello:  ClientHello;
    case server_hello:  ServerHello;
    case hello_verify_request: HelloVerifyRequest;  // New field
    case certificate:Certificate;
    case server_key_exchange: ServerKeyExchange;
    case certificate_request: CertificateRequest;
    case server_hello_done:ServerHelloDone;
    case certificate_verify:  CertificateVerify;
    case client_key_exchange: ClientKeyExchange;
    case finished: Finished;
  } body; } Handshake;

struct {
  ProtocolVersion client_version;
  Random random;
  SessionID session_id;
  opaque cookie<0..2^8-1>;                             // New field
  CipherSuite cipher_suites<2..2^16-1>;
  CompressionMethod compression_methods<1..2^8-1>; } ClientHello;

struct {
  ProtocolVersion server_version;
  opaque cookie<0..2^8-1>; } HelloVerifyRequest;