Network Security- Secure Socket Layer

Definition, SSL Concepts Connection and Service, SSL Architecture, SSL Record Protocol, Record Format, Higher Layer Protocol, Handshake Protocol- Change Cipher Specification and lert Protocol

1. NETWORK SECURITY Name of the Staff : Dr.M.FLORENCE DAYANA M.C.A.,M.Phil .,Ph.D ., Bon Secours College for Women Thanjavur .

2. SECURE SOCKET LAYER (SSL)

3. Secure Socket Layer (SSL) Protocol SSL was originated by Netscape Secure Sockets Layer  ( SSL ) is a computer networking  protocol  for securing connections between network application clients and servers over an insecure network, such as the internet . SSL is designed to make use of TCP to provide reliable end-to-end secure service.

4. The two important SSL Concepts are Connection: A connection is a transport that provides a suitable type of service , such connections are peer-peer relationship. Every connection is associated with one session Session: An SSL session is an associated between a client and a server. Sessions are created by Handshake protocol. Sessions are used to avoid the expensive negotiation of new security parameters. Web client Web server

5. SSL Architecture HTTP provides the transfer service for web client/server interaction. The three higher layer protocols (handshake, change cipher spec and Alert) of SSL is used in the management of SSL exchanges.

6. Provides basic security services to various higher-layer protocols. HTTP Handshake Protocol Change Cipher Spec Protocol Alert Protocol Provides 2 services for SSL connections : Confidentiality: Handshake protocol defines a shared secret key used for conventional encryption of SSL payloads. Message Integrity: Handshake protocol also defines a shared secret key used to form a Message A uthentication C ode (MAC). SSL Record Protocol

7. SSL Record Protocol Operation The first step is fragmentation into block(2 14 bytes) 2. Compression must be lossless or may not increase the content of the length. So the default compression algorithm is null 3. MAC shared the secret key. 4. The compression msg + MAC are encrypted using symmetric encryption. 5.SSL is to prepared a header consisting of following fields

8. SSL Record Format Content type(8 bits)-used to process the enclosed fragment. Major version(8 bits)- indicates the major version of SSL Minor version(8 bits) - indicates the minor version of SSL Compressed length – the length of the bytes of plaintext

9. The most complex part of SSL. Allows the server and client to authenticate each other. Negotiate encryption, MAC algorithm and cryptographic keys. Used before any application data are transmitted. Higher-Layer Protocols

10. Handshake Protocol

11. 2 . Change Cipher Spec Protocol Use SSL record protocol Update the cipher suite to be used on this connection It consists of single msg with single byte with the value 1 3 . Alert Protocol Used to convey SSL-related alerts to the peer entity. It consists of 2 bytes. The first bytes takes the value warning or fatal . If level is fatal means the SSL terminates the connection. The second byte contains code that indicates the specific alert.