Middleware for Secure Middleware for Secure EnvironmentsEnvironments

Presented byPresented byKemal Kemal AltıntaşAltıntaş

Hümeyra Topcu-AltıntaşHümeyra Topcu-AltıntaşOsman ŞenOsman Şen

Cherubim Security SystemCherubim Security System

Java based security system for secure Java based security system for secure communication over networkscommunication over networks

Developed at the UIUCDeveloped at the UIUC

Core Security ServicesCore Security Services

EncryptionEncryption: process to encode data to protect : process to encode data to protect it from attacks in the networkit from attacks in the network

Can be done with a variety of algorithms (such Can be done with a variety of algorithms (such as IDEA or DES), modes (such as ECB- as IDEA or DES), modes (such as ECB- Electgronic Code Book, CFB-Cipher Electgronic Code Book, CFB-Cipher Feedback, or CBC-Cipher Block Chaining) Feedback, or CBC-Cipher Block Chaining) and padding schemes (such as PKCS#5 or and padding schemes (such as PKCS#5 or PKCS#7).PKCS#7).

DecryptionDecryption: The opposite of encryption. Can : The opposite of encryption. Can be done with any of the above algorithms.be done with any of the above algorithms.

Core Security ServicesCore Security Services

Digital SignatureDigital Signature Electronic equivalent of a person’s signatureElectronic equivalent of a person’s signature Used to verify that a document or a message really Used to verify that a document or a message really

comes from a specific personcomes from a specific person Can be done with algorithms such as RSA, DSA or Can be done with algorithms such as RSA, DSA or

El GamalEl Gamal

Core Security ServicesCore Security Services

Digital Signature VerificationDigital Signature Verification Equivalent to comparing one’s signature to a Equivalent to comparing one’s signature to a

reference copyreference copy If the signature verifies, the document or the If the signature verifies, the document or the

message is assumed to be coming from the message is assumed to be coming from the specified personspecified person

Any of the above algorithms can be usedAny of the above algorithms can be used

Core Security ServicesCore Security Services

Secret HashingSecret Hashing Process of transforming a document into a unique Process of transforming a document into a unique

code that is relatively small, typically 128-256 bitscode that is relatively small, typically 128-256 bits It is desirable to have unique codes for each It is desirable to have unique codes for each

documentdocument Cherubim supports several hashing algorithms Cherubim supports several hashing algorithms

such as SHA-1 and MD5such as SHA-1 and MD5

Core Security ServicesCore Security Services

Secret Key Generation from a PassPhraseSecret Key Generation from a PassPhrase A secret key from a phrase that the user enters is A secret key from a phrase that the user enters is

generated using a hash algorithmgenerated using a hash algorithm Used to store private keys and such private Used to store private keys and such private

information on diskinformation on disk If the hashed secret is short, it is repeated to If the hashed secret is short, it is repeated to

increase the sizeincrease the size If it is long, the last blocks are xored with the first If it is long, the last blocks are xored with the first

blocksblocks

Authentication and Key NegotiationAuthentication and Key Negotiation Key negotiation is accomplished using Diffie-Hellman protocol.Key negotiation is accomplished using Diffie-Hellman protocol. Client sends a SignedDHMessage to the server. Client sends a SignedDHMessage to the server.

The message contains: client’s part of the key exchange, destination of the The message contains: client’s part of the key exchange, destination of the message, a timestamp, the algorithm to generate the key and the length of the message, a timestamp, the algorithm to generate the key and the length of the keykey

The message is signed by the user’s private keyThe message is signed by the user’s private key Server verifies the signature, timestamp and destination. The Server verifies the signature, timestamp and destination. The

timestamp gives a duration of 5 minutes of validity for each timestamp gives a duration of 5 minutes of validity for each messagemessage

Server sends a SignedDHMessage with the similar informationServer sends a SignedDHMessage with the similar information Client verifies the signature, timestamp and destinationClient verifies the signature, timestamp and destination Client and server generate a shared secret as described in the Client and server generate a shared secret as described in the

protocolprotocol Client and Server hash the secret into a secret session keyClient and Server hash the secret into a secret session key Session key expires after 1 hour and the whole process repeatedSession key expires after 1 hour and the whole process repeated

Diffie-Hellman Authentication Diffie-Hellman Authentication ProtocolProtocol

Client a

Session Key

HASHHASH

gab

<ga, destination, timestamp, algorithm> signature

Server b

Session Key

gab

<gb, destination, timestamp, algorithm> signature

Diffie Hellman Exchange ParametersDiffie Hellman Exchange Parameters

Parameters g and p are hard coded into the Parameters g and p are hard coded into the system in order to prevent an attack using system in order to prevent an attack using weak keysweak keys

p is a 2048 bit prime numberp is a 2048 bit prime number g is another smaller prime numberg is another smaller prime number

Classloader HierarchyClassloader Hierarchy

Primordial ClassesPrimordial Classes: Java core classes and : Java core classes and necessary cryptographic codenecessary cryptographic code

Jurassic ClassesJurassic Classes: The classes present on the : The classes present on the user’s home machine. user’s home machine.

Active Capability ClassesActive Capability Classes: Classes loaded by : Classes loaded by active capability loader. No more info in paperactive capability loader. No more info in paper

Initial Booting of the SystemInitial Booting of the System Client boots its OS and Java Virtual MachineClient boots its OS and Java Virtual Machine

Cherubim does not consider security at this levelCherubim does not consider security at this level Focuses on network securityFocuses on network security Local system should be careful about trojan horse OS or JVM Local system should be careful about trojan horse OS or JVM

and the authenticity of the java core classesand the authenticity of the java core classes User runs the boot program form the smart cardUser runs the boot program form the smart card Boot program prompts for passphraseBoot program prompts for passphrase

The channel between keyboard and JVM must be secureThe channel between keyboard and JVM must be secure Passphrase is hashed into keyPassphrase is hashed into key Key is used to decrypt the data on smart cardKey is used to decrypt the data on smart card

The memory access must be secure on local machineThe memory access must be secure on local machine Client machine connects to user’s home machineClient machine connects to user’s home machine Client begins key negotiations with the home machineClient begins key negotiations with the home machine

Requesting ClassesRequesting Classes

JurassicClassloader receives request for a classJurassicClassloader receives request for a class JurassicClassloader checks to see if the class is in cacheJurassicClassloader checks to see if the class is in cache If so, return itIf so, return it Else check if primordialClassloader can load it (i.e. is it in Else check if primordialClassloader can load it (i.e. is it in

classpath?). If so, return itclasspath?). If so, return it Else check if the session key expired. If so, negotiate and Else check if the session key expired. If so, negotiate and

get new keyget new key JurassicClassloader sends a SEClassRequest (signed, JurassicClassloader sends a SEClassRequest (signed,

encrypted request) to the home server over existing socketencrypted request) to the home server over existing socket Server verifies the signature, timestamp, description and Server verifies the signature, timestamp, description and

sequence number on the request messagesequence number on the request message

Class ResponseClass Response

Server loads the class from the disk to memoryServer loads the class from the disk to memory Server sends the class to client (in encrypted Server sends the class to client (in encrypted

form) form) JurassicClassloader verifies the signature, JurassicClassloader verifies the signature,

timestamp, destination and sequence numbertimestamp, destination and sequence number JurassicClassloader adds the class to the cacheJurassicClassloader adds the class to the cache Returns the class to the processReturns the class to the process

System SpecificSystem Specific Message DigestingMessage Digesting

Default: SHA-1Default: SHA-1 Alternatives: MD4, MD5, RIPE-MD 160Alternatives: MD4, MD5, RIPE-MD 160

Digital SignaturesDigital Signatures Default: SHA-1/RSADefault: SHA-1/RSA Alternatives: DSA, El GamalAlternatives: DSA, El Gamal

Session KeysSession Keys Default: IDEADefault: IDEA Alternatives: DES, Triple DES (3DES), Blowfish or SPEEDAlternatives: DES, Triple DES (3DES), Blowfish or SPEED

Passphrase HashingPassphrase Hashing Default: SHA-1Default: SHA-1

System SpecificSystem Specific Character EncodingCharacter Encoding

Default: UTF8Default: UTF8 Symmetric Key for Writing to StorageSymmetric Key for Writing to Storage

Default: IDEADefault: IDEA Diffie-Hellman Key Exchange ParamsDiffie-Hellman Key Exchange Params

Hardcoded into systemHardcoded into system

Antigone: A Flexible Antigone: A Flexible Framework for Secure Group Framework for Secure Group

CommunicationCommunicationby P.McDaniel, A.Prakash, P.Honeymanby P.McDaniel, A.Prakash, P.Honeyman

What is Antigone?What is Antigone?

Middleware layerMiddleware layer Provides flexible interfaces for defining policy Provides flexible interfaces for defining policy

in group applicationsin group applications Applications can define and implement a wide Applications can define and implement a wide

range of policiesrange of policies

Group Security PoliciesGroup Security Policies

Session rekeying policySession rekeying policy Application Message policyApplication Message policy Membership policyMembership policy Process failure policyProcess failure policy

Session rekeying policySession rekeying policy

Changes in group membership require the Changes in group membership require the session to be rekeyedsession to be rekeyed

Time-sensitive rekeyingTime-sensitive rekeying Leave-sensitive rekeyingLeave-sensitive rekeying Join-sensitive rekeyingJoin-sensitive rekeying Membership-sensitive rekeyingMembership-sensitive rekeying

Application message (Data security) Application message (Data security) policypolicy

States the types of security guarantees required States the types of security guarantees required for application messagesfor application messages

Types: integrity, confidentiality, group Types: integrity, confidentiality, group authenticity, sender authenticityauthenticity, sender authenticity

Vary from message to messageVary from message to message

Membership PolicyMembership Policy

What information about the membership is What information about the membership is delivered to the group membersdelivered to the group members

Antigone does not support confidentiality of Antigone does not support confidentiality of group membership because of the difficulties group membership because of the difficulties about hiding group membership from about hiding group membership from members and non-membersmembers and non-members

Process Failure PolicyProcess Failure Policy

States a set of failures to be detected and the States a set of failures to be detected and the security to be applied to the failure detection security to be applied to the failure detection mechanismmechanism

Need for secure failure detection to protect the Need for secure failure detection to protect the group from the masking of process failures by group from the masking of process failures by an adversaryan adversary

Antigone ArchitectureAntigone Architecture

Multicast/TCP

IP

Application

Predefined Policies

Broadcast Transport

Point-to-point Asymmetric Multicast Symmetric Multicast

Join Failure Detection

ApplicationMessage Policy

MembershipPolicy

Process FailurePolicy

Rekeying Policy

Rekey/GroupMembership

LeaveApplicationMessage

Mechanisms

Authenticate