{"id":706,"date":"2022-05-04T12:09:42","date_gmt":"2022-05-04T04:09:42","guid":{"rendered":"https:\/\/www.fanyamin.com\/wordpress\/?p=706"},"modified":"2022-05-04T12:10:45","modified_gmt":"2022-05-04T04:10:45","slug":"dtls-handshake","status":"publish","type":"post","link":"https:\/\/www.fanyamin.com\/wordpress\/?p=706","title":{"rendered":"DTLS handshake"},"content":{"rendered":"

DTLS record header<\/h1>\n

\"file\"<\/p>\n\n\n\n\n\n\n
<\/th>\n<\/th>\n<\/tr>\n<\/thead>\n
<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\n\n\n\n\n\n\n\n\n
DTLS Header Field<\/th>\nPurpose<\/th>\n<\/tr>\n<\/thead>\n
8-bit Message Type<\/td>\nThis field contains the type of DTLS record being sent. Valid types are as follows:
- ChangeCipherSpec: 0x14
- Alert: 0x15
- Handshake: 0x16
- Application Data: 0x17<\/td>\n<\/tr>\n
16-bit Protocol Version<\/td>\nThis field contains the DTLS protocol version. Valid values are as follows:
- DTLS 1.1: 0xFEFD<\/td>\n<\/tr>\n
16-bit Epoch<\/td>\nThis field contains the DTLS \u201cepoch\u201d which is a counter that is incremented each time the encryption state is changed (e.g. when generating new session keys).<\/td>\n<\/tr>\n
48-bit Sequence Number<\/td>\nThis field contains a sequence number which identifies this particular record. It is used by DTLS to maintain record ordering and check for retransmission need.<\/td>\n<\/tr>\n
16-bit Length<\/td>\nThis field contains the length of the data encapsulated in the DTLS record.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

DTLS Handshake Record header<\/h1>\n

\"file\"<\/p>\n

DTLS Handshake flow<\/h1>\n

\"file\"<\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n
TLS Header Field<\/th>\nPurpose<\/th>\n<\/tr>\n<\/thead>\n
8-bit Message Type<\/td>\nThis field contains the type of DTLS record being sent. Valid types are as follows:
- ChangeCipherSpec: 0x14
- Alert: 0x15
- Handshake: 0x16
- Application Data: 0x17<\/td>\n<\/tr>\n
16-bit Epoch<\/td>\nThis field contains the DTLS \u201cepoch\u201d which is a counter that is incremented each time the encryption state is changed (e.g. when generating new session keys).<\/td>\n<\/tr>\n
48-bit Sequence Number<\/td>\nThis field contains a sequence number which identifies this particular record. It is used by DTLS to maintain record ordering and check for retransmission need.<\/td>\n<\/tr>\n
16-bit Protocol Version<\/td>\nThis field contains the DTLS protocol version. Valid values are as follows:
- DTLS 1.1: 0xFEFD<\/td>\n<\/tr>\n
16-bit Length<\/td>\nThis field contains the length of the data encapsulated in the DTLS record.<\/td>\n<\/tr>\n
8-bit Handshake Type<\/td>\nThis field contains the handshake message type. Valid values are as follows:
- HelloRequest: 0x00
- ClientHello: 0x01
- ServerHello: 0x02
- Certificate: 0x0B
- ServerKeyExchange: 0x0C
- CertificateRequest: 0x0D
- ServerHelloDone: 0x0E
- CertificateVerify: 0x0F
- ClientKeyExchange: 0x10
- Finished: 0x14<\/td>\n<\/tr>\n
24-bit Length<\/td>\nThis field contains the length of the handshake message data.<\/td>\n<\/tr>\n
16-bit Sequence Number<\/td>\nThis field contains a sequence number.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Reference<\/h1>\n