Domain 3 - Security Engineering Flashcards
Common Criteria ISO 15408
Structured methodology for documenting security requirements,
documenting and validating
Evaluation Assurance Level 0
EAL0 – Inadequate assurance
Evaluation Assurance Level 1
EAL1 – Functionally tested
Evaluation Assurance Level 2
EAL2 – Structurally tested
Evaluation Assurance Level 3
EAL3 – Methodically tested and checked
Evaluation Assurance Level 4
EAL4 – Methodically designed, tested and reviewed
Evaluation Assurance Level 5
EAL5 – Semi formally designed and tested
Evaluation Assurance Level 6
EAL6 – Semi formally verified design and tested
Evaluation Assurance Level 7
EAL7 – Formally verified design and tested
Target of Evaluation (TOE):
The product
Protection Profile
Set of security requirements for a category of products that meet specific
consumer security needs
Security Target (ST):
dentifies the security properties of TOE
Security Functional Requirements (SFRs)
Specific individual security function
NIST SP 800-27
- Initiation; need expressed, purpose documented, impact assessment
- Development/Acquisition; system designed, purchased, programmed, developed or constructed.
- Implementation; system tested and installed, certification and accreditation
- Operation/Maintenance; performs function, security operations, audits
Primary Storage
Is a temporary storage area for data entering and leaving the CPU
Process states:• Stopped;
Process finishes or must be terminated
Process states:• Waiting
The process is ready for continued execution but is waiting for a device or access
Process states: Running;
Executes on the CPU and keeps going until it finishes, its time slice expires, or it is
blocked
Process states:• Ready;
Ready; process prepared to execute when CPU read
Multitasking
execute more than one task at the same time
Multiprocessing
more than one CPU is involved.
Multi-Threading:
Execute different parts of a program simultaneously
Single state machine
Operates in the security environment at the highest level of classification of the
information within the computer. In other words, all users on that system must have clearance to access
the info on that system.
Multi-state machine
Can offer several security levels without risk of compromising the system’s
integrity
CICS
Complex instructions. Many operations per instruction. Less number of fetches
RISC
Reduced instructions. Simpler operations per instruction. More fetches.
Segmentation
Dividing a computer’s memory into segments.
Protection Keying
Numerical values, Divides physical memory up into particular sized blocks, each
of which has an associated numerical value called a protection key
Paging
Divides memory address space into even size blocks called pages. To emulate that we have
more RAM than we have.
DEP, Data Execution Prevention
A system-level memory protection feature that is built into the DEP prevents code from being run from data pages such as the default heap, stacks, and memory pools
State Machine Mode
Describes a system that is always secure no matter what state it is in. If all
aspects of a state meet the requirements of the security policy, that state is considered secure. A
transition occurs when accepting input or producing output. A transition always results in a new state
(also called a state transition). A secure state machine model system always boots into a secure state,
maintains a secure state across all transitions, and allows subjects to access resources only in a secure
manner compliant with the security policy.
Information Flow Model –
Focuses on the flow of information. Information flow models are based on
a state machine model. The Bell-LaPadula and Biba models are both information flow models.
Information flow models don’t necessarily deal with only the direction of information flow; they can
also address the type of flow. Information flow models are designed to prevent unauthorized, insecure,
or restricted information flow, often between different levels of security (these are often referred to as
multilevel models). The information flow model also addresses covert channels by specifically
excluding all non-defined flow pathways.
Noninterference Model
Is loosely based on the information flow model. However, instead of being
concerned about the flow of information, the noninterference model is concerned with how the actions
of a subject at a higher security level affect the system state or the actions of a subject at a lower
security level. Basically, the actions of subject A (high) should not affect the actions of subject B (low)
or even be noticed by subject B. The noninterference model can be imposed to provide a form of
protection against damage caused by malicious programs such as Trojan horses
Confinement
To restrict the actions of a program. Simply put, process confinement allows a process
to read from and write to only certain memory locations and resources. This is also known as
sandboxing
Bounds
A process consist of limits set on the memory addresses and resources it can access. The
bounds state the area within which a process is confined or contained
Isolation
When a process is confined through enforcing access bounds that process runs in isolation.
Process isolation ensures that any behavior will affect only the memory and resources associated with
the isolated process
ACCESS CONTROL MATRIX
- Provides access rights to subjects for objects
- Access rights are read, write and execute
- Columns are ACL’s
- Rows are capability lists
- Supports discretionary access control
BELL-LAPADULA = MAC SUBJECTS/OBJECTS/CLEARANCES/
• Confidentiality model
• developed by DOD, thus classification
• Cannot read up (simple e=read security rule)
• Cannot write down (* property rule AKA CONFINEMENT PROPERTY). Exception is a trusted
subject.
• Uses access matrix to specify discretionary access control
• Use need to know principle
• Strong star rule: read and write capabilities at the same level
• First mathematical model defined
• tranquility principle in Bell-LaPadula prevents security level of subjects from being changed
once they are created
• Bell-LaPadula is concerned with preventing information flow from a high security level to a
low security level.
BIBA – MAC “if I in it INTEGRITY MODEL”
• Integrity model
• Cannot read down (simple e=read integrity rule)
• Simple integrity property
• cannot write up (* integrity)
• lattice based (least upper bound, greatest lower bound, flow policy)
• subject at one level of integrity cant invoke subject at a higher level of integrity
• Biba is concerned with preventing information flow from a low security level to a high security
level.
• Focus on protecting objects from external threat
CLARK WILSON
• integrity model
• Cannot be tampered, logged, and consistency
• Enforces segregation of duty
• Requires auditing
• Commercial use
• Works with SCI Constrained Data items, data item whose integrity is to be preserved
• Access to objects only through programs
• An integrity verification procedure (IVP) is a procedure that scans data items and confirms their
integrity.
Brewer and Nash
The Chinese Wall model provides a dynamic access control depending on user’s previous actions. This
model prevents conflict of interests from members of the same organization to look at information
that creates a conflict of another member of that organization.
Lipner Model
- Confidentiality and Integrity, BLP + Biba
* 1st Commercial Model
Graham-Denning
Focused on relationship between subjects and objects
TAKE-GRANT
Uses a direct graph to specify the rights that subjects can transfer to objects or that subjects can
take from other subjects
• Uses STATES and STATE TRANSITIONS
Take rule Allows a subject to take rights over an object
Grant rule Allows a subject to grant rights to an object
Create rule Allows a subject to create new rights
Remove rule Allows a subject to remove rights it has
ITSEC
• Refers to any system being evaluated as a target of evaluation (TOE).
• Does not rely on the notion of a TCB, and it doesn’t require that a system’s security components
be isolated within a TCB.
• Includes coverage for maintaining targets of evaluation after changes occur without requiring a
new formal evaluation.
Certification
Is evaluation of security features and safeguards if it meets requirements. Certification
is the comprehensive evaluation of the technical and nontechnical security features of an IT system and
other safeguards made in support of the accreditation process to establish the extent to which a
particular design and implementation meets a set of specified security requirements.
Accreditation
The formal declaration by the designated approving authority (DAA) that an IT system
is approved to operate in a particular security mode using a prescribed set of safeguards at an
acceptable level of risk. Once accreditation is performed, management can formally accept the
adequacy of the overall security performance of an evaluated system.
System accreditation
A major application or general support system is evaluated.
Site accreditation
The applications and systems at a specific, self-contained location are evaluated
Type accreditation
An application or system that is distributed to a number of different locations is
evaluate
Information Technology Security Evaluation Criteria ITSEC:
it is used in Europe only, not USA.
Addresses CIA. Unlike TCSEC it evaluates Functionality and assurance separately
Assurance from E0 to E6 (highest) and F1 to F10 (highest). Therefore a system can provide low
assurance and high functionality or vice-versa
ISO 27001
Focused on the standardization and certification of an organization’s information security management system (ISMS), security governance, a standard; ISMS. Info security minimum system
ISO 27002
A guideline which lists security control objectives and
recommends a range of specific security controls; more granular than 27001. 14 areas BOTH
INSPIRED FROM BS7799
COBIT 5
- Principle 1: Meeting Stakeholder Needs
- Principle 2: Covering the Enterprise End-to-End
- Principle 3: Applying a Single, Integrated Framework
- Principle 4: Enabling a Holistic Approach
- Principle 5: Separating Governance from Management
COBIT is used not only to plan the IT security of an organization but also as a guideline for auditors
TOCTTOU attack
Race condition exploits, and communication disconnects are known as state
attacks because they attack timing, data flow control, and transition between one system state to
another.
RACE
Two or more processes require access to the same resource and must complete their tasks in
the proper order for normal functions
Register
CPU also includes a limited amount of onboard memory, known as registers, that provide it
with directly accessible memory locations that the brain of the CPU, the arithmetic-logical unit (ALU),
uses when performing calculations or processing instructions, small memory locations directly in the
CPU.
Stack Memory Segment
Used by processors to communicate instructions and data to each other
Memory Addressing
When using memory resources, the processor must have some means of
referring to various locations in memory. The solution to this problem is known as addressing
Register Addressing
When the CPU needs information from one of its registers to complete
an operation, it uses a register address (for example, “register 1”) to access its contents.
Immediate Addressing
Is not a memory addressing scheme per se but rather a way of
referring to data that is supplied to the CPU as part of an instruction. For example, the CPU
might process the command “Add 2 to the value in register 1.” This command uses two
addressing schemes. The first is immediate addressing—the CPU is being told to add the value
2 and does not need to retrieve that value from a memory location—it’s supplied as part of the
command. The second is register addressing; it’s instructed to retrieve the value from register 1
Direct Addressing
In direct addressing, the CPU is provided with an actual address of the
memory location to access. The address must be located on the same memory page as the
instruction being executed. Direct addressing is more flexible than immediate addressing since
the contents of the memory location can be changed more readily than reprogramming the
immediate addressing’s hard-coded data.
Indirect Addressing
Uses a scheme similar to direct addressing. However, the memory
address supplied to the CPU as part of the instruction doesn’t contain the actual value that the
CPU is to use as an operand. Instead, the memory address contains another memory address
(perhaps located on a different page). The CPU reads the indirect address to learn the address
where the desired data resides and then retrieves the actual operand from that address.
Base + Offset Addressing
Uses a value stored in one of the CPU’s registers as the base location from which to begin counting. The CPU then adds the offset supplied with the
instruction to that base address and retrieves the operand from that computed memory location
Aggregation
SQL provides a number of functions that combine records from one or more tables to
produce potentially useful information. Aggregation is not without its security vulnerabilities.
Aggregation attacks are used to collect numerous low-level security items and combine them to create
something of a higher security level or value.
Inference
Involve combining several pieces of non-sensitive information to gain access to
information that should be classified at a higher level. However, inference makes use of the human
mind’s deductive capacity rather than the raw mathematical ability of modern database platforms.
Data Warehousing
:arge databases, store large amounts of information from a variety of databases for use with specialized analysis techniques.
Data dictionary
Commonly used for storing critical information about data, including usage, type,
sources, DBMS software reads the data
Substitution
Like shifting and rotating alphabets, can be broken by statistical looking at repeating
characters or repeats
Vernam
Cipher (one time pad): - key of a random set of non-repeating characters
Transposition
Permutation is used, meaning that letters are scrambled. The key determines
positions that the characters are moved to, for example vertical instead of horizontal
Null Cipher
Used in cases where the use of encryption is not necessary but yet the fact that no
encryption is needed must be configured in order for the system to work. Ex. Testing, stenography
Key space
Is the range of values that are valid for use as a key for a specific algorithm. A key space is
defined by its bit size. Bit size is nothing more than the number of binary bits (0s and 1s) in the key.
The key space is the range between the key that has all 0s and the key that has all 1s. Key space
doubles each time you add a bit to key length, which makes cryptanalysis more difficult
Key Clustering
When different encryption keys generate the same ciphertext from the same plaintext
message BAD
Synchronous
Each encryption or decryption request is performed immediately
Asynchronous
Encrypt/decrypt request are processed in queues
Hash Function
One-way mathematical operation that reduces a message or data file into a smaller
fixed length output. Encrypted using private key of sender
Registration Authority
Performs certificate registration services on behalf of a CA. RA verifies user
credentials
Certificate Authority
PKI, entity trusted by one or more users as an authority in a network that
issues, revokes, and manages digital certificates.
Key Space
Represents the total number of possible values of keys in a cryptographic algorithm for
the encryption of a plaintext block sequence to increase security by introducing additional
cryptographic variance. HOW HARD TO BRUTE FORCE
Transposition/permutation
Process of reordering plaintext to hide the message rambo = ombar
Diffusion
Mix location of plaintext throughout ciphertext, change of a single bit should drastically
change hash, dissipate pattern
Meet in the Middle
Attackers might use a meet-in-the-middle attack to defeat encryption algorithms
that use two rounds of encryption. This attack is the reason that Double DES (2DES) was quickly
discarded as a viable enhancement to the DES encryption (it was replaced by Triple DES (3DES,
TDES, EEE, EDE)
Block Cipher
Segregating plaintext into blocks and applying identical encryption algorithm and key
Cipher text or Cryptogram
Unintelligible message, encrypt text
PGP
Encrypt attached files
Salami
Removal of a small amount of money otherwise known as skimming
Zero-knowledge proof
Is a communication concept. A specific type of information is exchanged but
no real data is transferred, as with digital signatures and digital certificates. Understand split
knowledge. “magic door
Split knowledge
Means that the information or privilege required to perform an operation is divided
among multiple users. This ensures that no single person has sufficient privileges to compromise the
security of the environment. M of N Control (multiparty key recovery) is an example of split
knowledge.
Skipjack
Like many block ciphers, Skipjack operates on 64-bit blocks of text. It uses an 80-bit key
and supports the same four modes of operation supported by DES. Skipjack was quickly embraced by
the US government and provides the cryptographic routines supporting the Clipper and Capstone
encryption chips. However, Skipjack has an added twist—it supports the escrow of encryption keys
Key Clustering
When different encryption keys generate the same ciphertext from the same plaintext
message
Kirchhoff’s Principle
All but key, secure Synchronous and self-synchronous Random Number
Generators (RNGs)
Vigenere Cipher
Uses key words and numerous rows (traditionally 26), each one of which is offset by one.
Security Monitoring
• Reference Monitor and security kernel are used to determine whether a user should be allowed
to access an object
• “Complete mediation” means that all subjects must be authenticated and their access rights
verified before they can access any object
Stream-based Ciphers
Operate on one character or bit of a message (or data stream) at a time. The
Caesar cipher is an example of a stream and shift cipher. The one-time pad is also a stream cipher
because the algorithm operates on each letter of the plaintext message independently.
SUBSTITUTION, real-time.
Advantages
• bit by bit substitution with XOR & keystream;
• Emulates one time pad
• No size difference between plaintext and ciphertext
Disadvantages
• Can be difficult to implement correctly
• Generally weaker than block mode cipher
• Difficult to generate a truly random unbiased keystream
Wireless Stream Cipher Uses: WEP, WPA –use WEP if you have nothing else, RC4
Audio Visual
Block-based Ciphers
Ciphers operate on “chunks,” or blocks, of a message and apply the
encryption algorithm to an entire message block at the same time. The transposition ciphers are
examples of block ciphers. SUBSTITUTION & TRANSPOSITION
CBC Cipher Block Chaining
Blocks of 64 bits with -64bits initialization vector. Errors will propagate
ECB Electronic Code Book
Right block/left block pairing 1-1. Replication occurs. Secure short
messages
Cipher Feedback CFB
stream cipher where the cipher text is used as feedback into key generation.
errors will propagate
Output Feedback OFB
Stream cipher that generates the key but XOR-ing the plaintext with a key
stream. No errors will propagate
Counter (CTR)
Secure long messages. Most secure.
DEA Data Encryption Algorithm
64 block size and 56bit key with 8bits parity
16-rounds of substitution and transposition cryptosystem
Triple des
Three times encrypted DES, preferably with 3 different keys.
Actual key length = 168 bits. Uses 48 rounds of computations.
Replaced by AES Advanced Encryption Standard
AES supports
Key sizes of 128 bits, 192 bits, and 256 bits, and the US government has approved, blocks 128 bits
its use to protect classified data up to top secret
Rijndael Block Cipher Algorithm
For speed, simplicity and resistance against known attacks. Variable block length and variable key lengths (128,192 and 256 bits)
RC5
Variable algorithm up 0 to 2048 bits key size. a symmetric algorithm patented by Rivest, Shamir, and Adleman
(RSA) Data Security, the people who developed the RSA asymmetric algorithm. RC5 is a block
cipher of variable block sizes (32, 64, or 128 bits) that uses key sizes between 0 (zero) length
and 2,040 bits.
IDEA
International Data Encryption Algorithm 64 bit plaintext and 128 key length with
confusion and diffusion used in PGP software
Two fish
Key lengths 256 bits blocks of 128 in 16 rounds BEAT OUT BY Rijndal for AES based on Blowfish
Blowfish
By Bruce Schneider key lengths 32 to 448 bits, used on Linux systems that use
bcrypt (DES alternative)
Asymmetric Cryptography
- Sender and receiver have public and private keys.
- Public to encrypt a message, private to decrypt
- Slower than symmetric, secret key (100 to 1000)
RSA
Works with one way math with large prime numbers (aka trap door
functions). Can be used for encryption, key exchange and digital signatures)
Diffie Hellman Key exchange
About exchanging secret keys over an insecure medium without exposing the keys.
el Gamal
Works with discrete logarithms, based on Diffie Hellman
DSA Digital Signature Algorithm
The US Government Equivalent of the RSA algorithm
ECC -Elliptic Curve Cryptosystem
Mathematical properties of elliptical curves, IT REQUIRES FEWER RESOURCES THAN RSA. Used in low power systems (mobile phones etc.) BOTH a hashing
and an asymmetric key algorithm; MD5 & ECC
Hybrid Cryptography
Uses both asymmetrical and symmetrical encryption. SSL, PGP, IPSEC S/MIME
Message Digest
Summaries of a message’s content (not unlike a file checksum) produced by a
hashing algorithm, checksum?
SAML
XML-based convention for the organization and exchange of communication
authentication and authorization details between security domains, often over web protocols. SAML is
often used to provide a web-based SSO (single sign-on) solution. If an attacker can falsify SAML
communications or steal a visitor’s access token, they may be able to bypass authentication and gain
access
SAML is a common protocol used for SSO on the Internet.
Best choice to support a federated identity management system,
Does not have a security mode and relies on TLS and digital signatures
If home organization offline implement a cloud based system user training about SSO directs a good
idea
SPML
Allow platforms to generate and respond to provisioning requests It is a newer framework based on
XML but specifically designed for exchanging user information for federated identity single sign-on
purposes. It is based on the Directory Service Markup Language (DSML), which can display LDAPbased directory service information in an XML format
Substitution character
shifting 3 character (C3) for example in the one (mono-alphabet) alphabet
system
Cipher disks
2 rotating disks with an alphabet around it
public key infrastructure
In the public key infrastructure, certificate authorities
(CAs) generate digital certificates containing the public keys of system users. Users then distribute
these certificates to people with whom they want to communicate. Certificate recipients verify a
certificate using the CA’s public key.
X.509 standard = PKI
Serial number, owner, issuer name
Integrity (hash code and message digest), access control, confidentiality (by encryption),
authentication (digital certificates) and non-repudiation (digital signatures)
issuer signs a certificate
If you only want to check if a mail is not altered: use digital signature! Proves that the signature was
provided by the intended signer
trust anchor = public key that has been verified and that’s trusted
Digital signatures
• No modifications allowed
• Identity can be derived
• Works with a one-way hash (message digest), like SHA-1 (512 bit blocks) or MD5 (128 bits
digest) or HMAC that uses a key
• Acceptable encryption algorithms choices – DSA, RSA, ECDSA
HASH it and ENCRYPT message digest
Correct way to create and use a digital signature – hash the document, encrypt only the hash with the
sender’s private key, send both the plain text document and the encrypted hash to recipient
Digital signatures
• No modifications allowed
• Identity can be derived
• Works with a one-way hash (message digest), like SHA-1 (512 bit blocks) or MD5 (128 bits
digest) or HMAC that uses a key
• Acceptable encryption algorithms choices – DSA, RSA, ECDSA
HASH it and ENCRYPT message digest
Correct way to create and use a digital signature – hash the document, encrypt only the hash with the
sender’s private key, send both the plain text document and the encrypted hash to recipient
S/Mime
Confidentiality (encryption) Integrity (using PKCS X.509 PKI) and non-rep through signed
message digests
PEM
Privacy Enhanced Email Encryption (AES) PKI X.509 and RSA
Message Security protocol
Military X.400. Sign, Encrypt, Hash
Pretty Good Privacy
Uses IDEA and RSA instead
Digital Certificates
Contain specific identifying information and their construction is governed by international standard
(X.509), creation and validation of digital certificates
Who signs a digital certificate – some one vouching for person not the person.
CRLs
Certificate Revocation Lists are maintained by the various certificate authorities and contain
the serial numbers of certificates that have been issued by a CA and have been revoked along with the
date and time the revocation went into effect
Hashing
ATTACK HASH BY BRUTE FORCE and dictionary
Requirements for HASH (Message Digests)
• works on non-fixed length input
• must be relatively easy to compute for any input
• function must be one way
Most used are MD5 (message Digest 128 bits) and SHA1 (signature hashing algorithm 160 bits)
Most used are MD5 (message Digest 128 bits) and SHA1 (signature hashing algorithm 160 bits)
MD5 – hashing algorithm . It also processes 512-bit blocks of the message, but it uses four distinct
rounds of computation to produce a digest of the same length as the MD2 and MD4 algorithms (128
bits). MD5 has the same adding requirements as MD4—the message length must be 64 bits less than a
multiple of 512 bits. MD5 implements additional security features that reduce the speed of message
digest production significantly. Unfortunately, recent cryptanalytic attacks demonstrated that the MD5
protocol is subject to collisions, preventing its use for ensuring message integrity. it is possible to create
two digital certificates from different public keys that have the same MD5 hash.
CRL’s of a PKI environment holds serial numbers
SHA1
Was designed by NIST and NSA to be used in digital signatures
Standard is SHA3 most still use SHA2
root Certificate Authority (CA) must certify its own public key pair
cross certification does not check authenticity of the certificates in the certificates path; MD5 not good
for securing passwords
Traffic analysis
inference of information from analysis of traffic
Traffic padding
Generation of spurious data units
Collision
Same message digest as a result of hashing
Ciphertext Only Attack
attacker sees only the ciphertext, one of the most difficult
Known Plaintext
Attacker knowns both cipher and plaintext
Chosen Plaintext
Offline attack (attacker prepares list of plaintexts) -lunch box attack
Online attack
Attacker chooses the plaintext based on the ciphertext already received)
Chosen ciphertext
attacker chooses both the plaintext values and the Ciphertext values, cherry
picking, feed info and based on what you learned get key
Birthday Attack
Collisions appear much faster, birthdays match
POODLE
(Padding Oracle on Downgraded Legacy Encryption) attack helped force the movement
from SSL 3.0 to TLS because it allowed attackers to easily access SSL encrypted messages
Security perimeter
Line between TCB and outside
Skip
is a distribution protocol
RC4 - is a stream cipher
RC5 and RC6 are block cipher
Digital Rights Management
Uses encryption to enforce copyright restrictions on digital media. serves to bring U.S. copyright law
into compliance with terms of two World Intellectual Property Organization (WIPO) treaties. The first
major provision of the DMCA is the prohibition of attempts to circumvent copyright protection
mechanisms placed on a protected work by the copyright holder
Applets
These code objects are sent from a server to a client to perform some action. In fact, applets
are actually self-contained miniature programs that execute independently of the server that sent them.
Java applets
Are simply short Java programs transmitted over the Internet to perform operations on a
remote system.
ActiveX
Controls are Microsoft’s answer to Sun’s Java applets. Operate in a similar fashion, but they
are implemented using a variety of languages(C, C + +, Java).
Active X vs Java applets
Two key distinctions between Java applets and ActiveX controls.
• First, ActiveX controls use proprietary Microsoft technology and, therefore, can execute only on
systems running Microsoft browsers.
• Second, ActiveX controls are not subject to the sandbox restrictions placed on Java applets.
They have full access to the Windows operating environment and can perform a number of
privileged actions
Kerchoff principle
A cryptographic system should be secure even if everything about the system,
except the key, is public knowledge
Kerchoff principle
A cryptographic system should be secure even if everything about the system, except the key, is public knowledge.
Side-channel attack
Is a passive, noninvasive attack intended to observe the operation of a device.
When the attack is successful, the attacker is able to learn valuable information contained within the
smartcard, such as an encryption key
Transitive Trust
Transitive trust is the concept that if A trusts B and B trusts C, then A inherits trust
of C through the transitive property — which works like it would in a mathematical equation: if a = b,
and b = c, then a = c. A transitive trust extends the trust relation ship between the two security domains
to all of their subdomains.
Nontransitive trust
Exists between two security domains, which could be within the same
organization or between different organizations. It allows subjects in one domain to access objects in
the other domain. A nontransitive trust enforces the principle of least privilege and grants the trust to a
single domain at a time
Humidity
40% static electricity up to 20.000 volts
NORMAL 40-60% up to 4000 volts
60% corrosion
Classes
- A Common WATER, SODA ACID (take away temp)
- B Liquids GAS/CO2, SODA ACID (takes away fuel)
- C Electrical GAS/CO2 (displace O2)
- D Metals DRY POWDER
- WATER suppress temperature
- SODA ACID reduces fuel supply
- CO2 reduces oxygen
- HALON chemical reaction
Fire extinguishers should be 50 feet from equipment and toward the doo
Heat
- Computer hardware 175F (80c)
- Magnetic storage 100F (37c)
- Paper 350F (176c)
HALON
FM-200 most common replacement (others: CEA, NAF, FE-13 Argon INERGEN Low Pressure
Water)
RESISTANCE
• Walls: 1 hour fire rating and adjacent room with paper 2 hours
WALL RESISTANCE
• Walls: 1 hour fire rating and adjacent room with paper 2 hours
TPM
Trusted Platform Module is both a specification for a cryptoprocessor chip on a mainboard and
the general name for implementation of the specification. A TPM chip is used to store and process
cryptographic keys for the purposes of a hardware supported/ implemented hard drive encryption
system. Generally, a hardware implementation, rather than a software-only implementation of hard
drive encryption, is considered to be more secure.
