In Cryptography, an initialization vector should be which of the following?

In Cryptography, an initialization vector should be which of the following?

• Unique and unpredicatable
• Repeatable and random
• Repeatable and unique
• Unique and predictable 

EXPLANATION

An initialization vector (IV) should be unique and unpredictable. To prevent an attack, an IV must not be repeated with a given key and should appear random.

SOURCE

https://en.wikipedia.org/wiki/Initialization_vector

 

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Spyware most likely uses which of the following types of cookies?

Spyware most likely uses which of the following types of cookies?

• Poisonous
• Tracking
• Transport
• Session 

EXPLANATION

Cookies are small amounts of data sent from a website to a computer. In Windows, most cookies are stored as text files in the logged-on user’s Temporary Internet Files folder. Websites use the encoded information in cookies to “remember” information such as website visits, previous authentication attempts and the status of current logins. Some websites use cookies to compile browsing history records, and it’s also possible for hackers to impersonate someone’s login session by stealing his or her cookies. Therefore, cleaning cookies off your business computers on a regular basis is a good security practice.

1.Click on the “Start” button and select “Control Panel.”

2.Click on “Internet Options" to bring up the Internet Properties dialog box.
3.Click the “Delete” button under Browsing History on the General tab.

4.Check the “Cookies” box, and uncheck everything else.

5.Click “Delete.”

Warnings

• Some cookies in your Temporary Internet Files folder are just pointers to their actual location in C:\Windows\Cookies and may not clear out when you empty out the folder in Internet Options. But if you delete them manually, both the pointer and the actual file will be removed.
• Your Temporary Internet Files folder is in the following location on a Windows 7 system (substitute “username” for your own account user name):
• C:\Users\username\AppData\Local\Microsoft\Windows\Temporary Internet Files
• This is a hidden folder that you can make visible in Windows Explorer by clicking “Tools,” then “Folder Options,” and then “Show hidden files, folders, and drives” from the View tab.
• Delete any files beginning with “cookie:”.

 

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Which of the following algorithms is an asymmetric encryption algorithm?

Which of the following algorithms is an asymmetric encryption algorithm?

• Rijndael
• Diffie-Hellman
• RC6
• AES 

EXPLANATION

 What is an asymmetric algorithm?

Asymmetric algorithms (public key algorithms) use different keys for encryption and decryption, and the decryption key cannot (practically) be derived from the encryption key. Asymmetric algorithms are important because they can be used for transmitting encryption keys or other data securely even when the parties have no opportunity to agree on a secret key in private.

Types of Asymmetric algorithms

Types of Asymmetric algorithms (public key algorithms):
– RSA
– Diffie-Hellman
– Digital Signature Algorithm
– ElGamal
– ECDSA
– XTR
Asymmetric algorithms examples:

RSA Asymmetric algorithm

Rivest-Shamir-Adleman is the most commonly used asymmetric algorithm (public key algorithm). It can be used both for encryption and for digital signatures. The security of RSA is generally considered equivalent to factoring, although this has not been proved.
RSA computation occurs with integers modulo n = p * q, for two large secret primes p, q. To encrypt a message m, it is exponentiated with a small public exponent e. For decryption, the recipient of the ciphertext c = me (mod n) computes the multiplicative reverse d = e-1 (mod (p-1)*(q-1)) (we require that e is selected suitably for it to exist) and obtains cd = m e * d = m (mod n). The private key consists of n, p, q, e, d (where p and q can be omitted); the public key contains only n and e. The problem for the attacker is that computing the reverse d of e is assumed to be no easier than factorizing n.
The key size should be greater than 1024 bits for a reasonable level of security. Keys of size, say, 2048 bits should allow security for decades. There are actually multiple incarnations of this algorithm; RC5 is one of the most common in use, and RC6 was a finalist algorithm for AES.

Diffie-Hellman

Diffie-Hellman is the first asymmetric encryption algorithm, invented in 1976, using discrete logarithms in a finite field. Allows two users to exchange a secret key over an insecure medium without any prior secrets.
Diffie-Hellman (DH) is a widely used key exchange algorithm. In many cryptographical protocols, two parties wish to begin communicating. However, let’s assume they do not initially possess any common secret and thus cannot use secret key cryptosystems. The key exchange by Diffie-Hellman protocol remedies this situation by allowing the construction of a common secret key over an insecure communication channel. It is based on a problem related to discrete logarithms, namely the Diffie-Hellman problem. This problem is considered hard, and it is in some instances as hard as the discrete logarithm problem.
The Diffie-Hellman protocol is generally considered to be secure when an appropriate mathematical group is used. In particular, the generator element used in the exponentiations should have a large period (i.e. order). Usually, Diffie-Hellman is not implemented on hardware.

Digital Signature Algorithm

Digital Signature Algorithm (DSA) is a United States Federal Government standard or FIPS for digital signatures. It was proposed by the National Institute of Standards and Technology (NIST) in August 1991 for use in their Digital Signature Algorithm (DSA), specified in FIPS 186 [1], adopted in 1993. A minor revision was issued in 1996 as FIPS 186-1 [2], and the standard was expanded further in 2000 as FIPS 186-2 [3]. Digital Signature Algorithm (DSA) is similar to the one used by ElGamal signature algorithm. It is fairly efficient though not as efficient as RSA for signature verification. The standard defines DSS to use the SHA-1 hash function exclusively to compute message digests.
The main problem with DSA is the fixed subgroup size (the order of the generator element), which limits the security to around only 80 bits. Hardware attacks can be menacing to some implementations of DSS. However, it is widely used and accepted as a good algorithm.

ElGamal

The ElGamal is a public key cipher – an asymmetric key encryption algorithm for public-key cryptography which is based on the Diffie-Hellman key agreement. ElGamal is the predecessor of DSA.

ECDSA

Elliptic Curve DSA (ECDSA) is a variant of the Digital Signature Algorithm (DSA) which operates on elliptic curve groups. As with Elliptic Curve Cryptography in general, the bit size of the public key believed to be needed for ECDSA is about twice the size of the security level, in bits.

XTR

XTR is an algorithm for asymmetric encryption (public-key encryption). XTR is a novel method that makes use of traces to represent and calculate powers of elements of a subgroup of a finite field. It is based on the primitive underlying the very first public key cryptosystem, the Diffie-Hellman key agreement protocol.
From a security point of view, XTR security relies on the difficulty of solving discrete logarithm related problems in the multiplicative group of a finite field. Some advantages of XTR are its fast key generation (much faster than RSA), small key sizes (much smaller than RSA, comparable with ECC for current security settings), and speed (overall comparable with ECC for current security settings).

Symmetric and asymmetric algorithms

Symmetric algorithms encrypt and decrypt with the same key. Main advantages of symmetric algorithms are their security and high speed. Asymmetric algorithms encrypt and decrypt with different keys. Data is encrypted with a public key, and decrypted with a private key. Asymmetric algorithms (also known as public-key algorithms) need at least a 3,000-bit key to achieve the same level of security of a 128-bit symmetric algorithm. Asymmetric algorithms are incredibly slow and it is impractical to use them to encrypt large amounts of data. Generally, symmetric algorithms are much faster to execute on a computer than asymmetric ones. In practice they are often used together, so that a public-key algorithm is used to encrypt a randomly generated encryption key, and the random key is used to encrypt the actual message using a symmetric algorithm. This is sometimes called hybrid encryption.

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Which display server protocol aims to be the successor to the X Window System?

Which display server protocol aims to be the successor to the X Window System?

• Surfects
• Wayland
• Compositux
• Mir

EXPLANATION

 

Some people have attempted writing alternatives to and replacements for X. Historical alternatives include Sun's NeWS and NeXT's Display PostScript, both PostScript-based systems supporting user-definable display-side procedures, which X lacked. Current alternatives include:

• macOS (and its mobile counterpart, iOS) implements its windows system, which is known as Quartz. When Apple Inc. bought NeXT, and used NeXTSTEP to construct Mac OS X, it replaced Display PostScript with Quartz. Mike Paquette, one of the authors of Quartz, explained that if Apple had added support for all the features it wanted to include into X11, it would not bear much resemblance to X11 nor be compatible with other servers anyway.^[13]
• Android, which runs on the Linux kernel, uses its own system for drawing the user interface known as SurfaceFlinger. 3D rendering is handled by EGL.
• Wayland is being developed by several X.Org developers as a prospective replacement for X. It works directly with the GPU hardware, via DRI. Wayland can run an X.org server as a client, which can be rootless.^[14] A proprietary port of the Wayland backend to the Raspberry Pi was completed in 2013.^[15] The project reached version 1.0 in 2012. Like Android, Wayland is EGL-based.
• Mir is a project from Canonical Ltd. with goals similar to Wayland.^[16] Mir is intended to work with mobile devices using ARM chipsets (a stated goal is compatibility with Android device-drivers) as well as x86 desktops. Like Android, Mir/UnityNext are EGL-based. Backwards compatibility with X client-applications is accomplished via Xmir.
• Other alternatives attempt to avoid the overhead of X by working directly with the hardware; such projects include DirectFB.^[17] (The Direct Rendering Infrastructure (DRI), which aims to provide a reliable kernel-level interface to the framebuffer, might^{[citation needed]} make these efforts redundant.)

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What is one of the main reasons to implement a business continuity plan (BCP)?

What is one of the main reasons to implement a business continuity plan (BCP)?

• React to disasters quickly
• Decrease liability
• Comply with regulations
• Keep a company up and running 

EXPLANATION

Companies today face an unprecedented number of exposures. The frequency and severity of weather-related events seem to be increasing and reliance on a complex network of technology and supply chains is expanding. Both trends leave businesses susceptible to a variety of existing and emerging risks. Managing these risks by developing a business continuity strategy is key to the survival of any organization.

• Identify the scope of the plan.
• Identify key business areas.
• Identify critical functions.
• Identify dependencies between various business areas and functions.
• Determine acceptable downtime for each critical function.
• Create a plan to maintain operations.

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