CSCI 415: Computer and Network Security Dr. Nazli HardySSL, IPSec, S/MIMEInternet Security Protocols and Standards Secure Sockets Layer (SSL) / Transport Layer Security (TLS) IPv4 and IPv6 Security S/MIME (Secure/Multipurpose Internet Mail Extension)CSCI 415: Computer and Network Security Dr. Nazli HardySSL, IPSec, S/MIMESecure Sockets Layer (SSL) One of the most widely used security service is the SSL transport layer security service– originally developed by Netscape– version 3 designed with public input subsequently became Internet standard RFC2246: Transport Layer Security (TLS) use TCP to provide a reliable end-to-end service may be provided in underlying protocol suite (and is transparent to applications) or embedded in specific packagesCSCI 415: Computer and Network Security Dr. Nazli HardySSL, IPSec, S/MIMESSL Protocol Stack SSL session SSL connectionCSCI 415: Computer and Network Security Dr. Nazli HardySSL, IPSec, S/MIMESSL Record Protocol Services Defines 2 services for SSL connections: message integrity– defines a shared secret key that is used to form a message authentication code (MAC), which is similar to HMAC confidentiality– defines a shared secret key that is used for conventional encryption of SSL payloads. – the message is compressed before being concatenated with the MACand encrypted, with a range of ciphers being supported as shown.– AES, IDEA, RC2-40, DES-40, DES, 3DES, Fortezza, RC4-40, RC4-128CSCI 415: Computer and Network Security Dr. Nazli HardySSL, IPSec, S/MIMESSL Record Protocol OperationCSCI 415: Computer and Network Security Dr. Nazli HardySSL, IPSec, S/MIMESSL Alert Protocol conveys SSL-related alerts First byte indicates severity• Warning (1)• or fatal (2) – will terminate connection. Other connections on the same session may continue, but no new connections on this session may be established Second byte contains a code that indicates the specific alert • warning: close notify, no certificate, bad certificate, unsupported certificate, certificate revoked, certificate expired, certificate unknown• fatal: unexpected message, bad record MAC, decompression failure, handshake failure As with other applications that use SSL, alert messages are compressed and encryptedCSCI 415: Computer and Network Security Dr. Nazli HardySSL, IPSec, S/MIMESSL Handshake Protocol allows server & client to:– authenticate each other– to negotiate encryption & MAC algorithms– to negotiate cryptographic keys to be used comprises a series of messages in phases1. Establish Security Capabilities2. Server Authentication and Key Exchange3. Client Authentication and Key Exchange4. Finish SSL Change Cipher Spec Protocol – one of 3 SSL specific protocols which use the SSL Record protocol– a single message– causes pending state to become currentCSCI 415: Computer and Network Security Dr. Nazli HardySSL, IPSec, S/MIMEIP Security various application security mechanisms– eg. S/MIME, PGP,, SSL/HTTPS security concerns cross protocol layers hence would like security implemented by the network for all applications authentication & encryption security features included in next-generation IPv6 also usable in existing IPv4CSCI 415: Computer and Network Security Dr. Nazli HardySSL, IPSec, S/MIMEIP Headers IPv4  IPv6DataDatagram Length (bytes)13-bit fragmentation offsetHeader Checksum32-bit Source IP address32-bit Destination IP addressOptions (if any)Time To LiveUpper-layerprotocolType of serviceVersionHeaderLengthFlags16-bit Identifier32 bitsDataFlow LabelNext Header128-bit Source IP address128-bit Destination IP addressPayload LengthVersionTrafficClass32 bitsHop LimitCSCI 415: Computer and Network Security Dr. Nazli HardySSL, IPSec, S/MIMEIPSec IP-level security encompasses three functional areas: – Authentication – this mechanism assures that a received packet was transmitted by the party identified as the source in the packet header, and that the packet has not been altered in transit– Confidentiality – this facility enables communicating nodes to encrypt messages to prevent eavesdropping by third parties – Key management – this facility is concerned with the secure exchange of keys.  The key management IPSec provides the capability to secure communications across a LAN, across private and public WANs, and across the InternetCSCI 415: Computer and Network Security Dr. Nazli HardySSL, IPSec, S/MIMEIPSec UsesThe principal feature of IPSec that enables it to support varied applications is that it can encrypt and/or authenticate alltraffic at the IP level. Thus, all distributed applications, including remote logon, client/server, e-mail, file transfer, Web access, and so on, can be secured.CSCI 415: Computer and Network Security Dr. Nazli HardySSL, IPSec, S/MIMEBenefits of IPSec in a firewall/router provides strong security to all traffic crossing the perimeter in a firewall/router is resistant to bypass is below transport layer, hence transparent to applications can be transparent to end users can provide security for individual users secures routing architectureCSCI 415: Computer and Network Security Dr. Nazli HardySSL, IPSec, S/MIMES/MIME (Secure/Multipurpose Internet Mail Extensions) security enhancement to MIME email– original Internet RFC822 email was text only– MIME provided support for varying content types (text, images, video audio, application)– S/MIME adds security enhancements S/MIME provides the ability to sign and/ or encrypt email messages S/MIME support in many mail agents– eg MS Outlook, Firefox, Mac Mail etcCSCI 415: Computer and Network Security Dr. Nazli HardySSL, IPSec, S/MIMES/MIME Functions S/MIME content-types support four new functions:Enveloped data: This consists of encrypted content of any type and encrypted-content encryption keys for one or more recipients.Signed data: A digital signature is formed by taking the message digest of the content to be signed and then encrypt that with the private key of the signer. The content plus signature are then encoded using base64 encoding. A signed data message can only be viewed by a recipient with S/MIME capability.Clear-signed data: As with signed data, a digital signature of the content is formed. However, in this case, only the digital signature is encoded using base64. As a result, recipients without S/MIME capability