Application Layer Security Protocols

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• published: 01 Jun 2016
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Don't hesitate to comment below if you have any questions or additional phrases Application Layer Security Protocols By: Mudassar Hayee Jasbir Singh “This report was prepared for Professor L. Orozco-Barbosa in partial fulfillment of the requirements for the course ELG/CEG 4183” SITE University of Ottawa ,Topics That Will Be Discussed Security over the internet Introduction (chapter 7 of this course) Firewalls Authentication and key distribution systems Keberos SESAME Security enhanced application protocols Electronic Mail S/MIME Remote Terminal Access TELNET ,Security Over the Internet (Introduction) Why do we need security? Packet sniffing IP Spoofing Denial of Service (DOS) We desire security to address these main concerns: Secrecy (encryption) Authentication (confirm identity) Message integrity ,Security Over the Internet (Introduction) Techniques used: Network layer security Cryptography Public key encryption Digital signatures Trusted intermediaries Application layer security Firewalls Top 3 myths about firewalls Protocols Electronic mail PGP– discussed in class! S/MIME Remote communication Telnet WWW transactions (HTTP) Discussed in class! ,Application Layer Firewalls A firewall is an intermediate system that can be placed between two networks to protect one from the other. A firewall is a host running proxy servers, which control the network access. ,Authentication and Key Distribution Systems Authentication is a problem that can be tackled by providing a password to access the resource. A key distribution system to authenticate a system (ie. public key encryption) makes it very secure. ,Kerberos Is a protocol that provides authentication and authorization. It uses a symmetric key which is based on the password the client entered. ,How Kerberos Works: Client(C) wants to connect to application server(V). 1. Client sends his name and name of TGS server to AS. 2. AS replies with a TGT that is encrypted with a key based on the client’s password. If the client types in the correct password, the client will be able to decipher the message and obtain TGT. ,How Kerberos Works(cont’d): 3. The client sends the TGT to the TGS. The TGT contains encrypted identification and time stamp information by a key that is shared between the AS and the TGS. 4. Once the AS has been verified by the TGS, the TGS gives access to the application server. ,How Kerberos Works(cont’d): 5. The client sends the message to the application server(V). The client encrypts the message with a public key. 6. This is an optional message when the user requires authentication by the verifier. ,SESAME Was developed because many companies were either not protecting themselves or buying an insurance policy. Objective was to define and implement protocols for authentication, access control, data confidentiality, and data integrity. An extension to Kerberos ,SESAME on-line Authorities AS: authenticates the user. PAS: returns the appropriate certificate for the user. KDS: is used to generate the keys to talk with the application. ,How SESAME works: The client sends authenticator message to AS. The AS uses the public key that was obtained from PAS. Once the digital signature has been verified on the authenticator, the client has been authenticated to the system. The AS will now sends the client’s public key encrypted by a session key generated by AS. AS will also send an authenticator digitally signed with it’s private key. ,How SESAME works(cont’d): The client will now verify this authenticator with AS’s public key that was obtained from AS’s certificate. If it has been verified, the AS has been authenticated to the client. ,Security Enhanced Application Protocols At the application layer, security services must be defined, implemented and incorporated into each application individually. ie. the application developer needs to address the issue of security. ,Electronic Mail The US Postal service (USPS) recently announced their PosteCS service. In the future they promise full support for digita