Due Care implies that not only has a party not been negligent or careless, but also that he/she has been guilty of no violation of law in relation to the subject mater or transaction which constitutes the cause of action. Due Care and Reasonable Care are used interchangeably. The definitions of Due Care given in the other answers re from Blacks Law Dictionary, Abridged Fifth Edition, West Publishing Company, St. Paul Minnesota, 1983.

Section: Security Operations
Explanation/Reference:

"Data Normalization
Normalization is an important part of database design that ensures that attributes in a table
depend only on the primary key. This process makes it easier to maintain data and have
consistent reports.
Normalizing data in the database consists of three steps:
1.)Eliminating any repeating groups by putting them into separate tables
2.)Eliminating redundant data (occurring in more than one table)
3.)Eliminating attributes in a table that are not dependent on the primary key of that table"
Pg. 62 Krutz: The CISSP Prep Guide: Gold Edition

A stream cipher treats the message as a stream of bits or bytes and performs mathematical functions on them individually. The key is a random value input into the stream cipher, which it uses to ensure the randomness of the keystream data. They are more suitable for hardware implementations, because they encrypt and decrypt one bit at a time. They are intensive because each bit must be manipulated, which works better at the silicon level. Block ciphers operate a the block level, dividing the message into blocks of bits. Cipher Block chaining (CBC) and Electronic Code Book (ECB) are operation modes of
DES, a block encryption algorithm.
Source: WALLHOFF, John, CBK#5 Cryptography (CISSP Study Guide), April 2002 (page
2).

CHAP is not used within IPSEC or IKE. CHAP is an authentication scheme used by
Point to Point Protocol (PPP) servers to validate the identity of remote clients. CHAP periodically
verifies the identity of the client by using a three-way handshake. This happens at the time of
establishing the initial link (LCP), and may happen again at any time afterwards. The verification is
based on a shared secret (such as the client user's password).
After the completion of the link establishment phase, the authenticator sends a "challenge"
message to the peer.
The peer responds with a value calculated using a one-way hash function on the challenge and
the secret combined.
The authenticator checks the response against its own calculation of the expected hash value. If
the values match, the authenticator acknowledges the authentication; otherwise it should
terminate the connection.
At random intervals the authenticator sends a new challenge to the peer and repeats steps 1
through 3.
The following were incorrect answers:
Pre Shared Keys
In cryptography, a pre-shared key or PSK is a shared secret which was previously shared
between the two parties using some secure channel before it needs to be used. To build a key
from shared secret, the key derivation function should be used. Such systems almost always use
symmetric key cryptographic algorithms. The term PSK is used in WiFi encryption such as WEP or
WPA, where both the wireless access points (AP) and all clients share the same key.
The characteristics of this secret or key are determined by the system which uses it; some system
designs require that such keys be in a particular format. It can be a password like 'bret13i', a
passphrase like 'Idaho hung gear id gene', or a hexadecimal string like '65E4 E556 8622 EEE1'.
The secret is used by all systems involved in the cryptographic processes used to secure the
traffic between the systems.
Certificat Based Authentication
The most common form of trusted authentication between parties in the wide world of Web commerce is the exchange of certificates. A certificate is a digital document that at a minimum includes a Distinguished Name (DN) and an associated public key.
The certificate is digitally signed by a trusted third party known as the Certificate Authority (CA). The CA vouches for the authenticity of the certificate holder. Each principal in the transaction presents certificate as its credentials. The recipient then validates the certificate's signature against its cache of known and trusted CA certificates. A "personal certificate" identifies an end user in a transaction; a "server certificate" identifies the service provider.
Generally, certificate formats follow the X.509 Version 3 standard. X.509 is part of the Open Systems Interconnect (OSI) X.500 specification.
Public Key Authentication Public key authentication is an alternative means of identifying yourself to a login server, instead of typing a password. It is more secure and more flexible, but more difficult to set up.
In conventional password authentication, you prove you are who you claim to be by proving that you know the correct password. The only way to prove you know the password is to tell the server what you think the password is. This means that if the server has been hacked, or spoofed an attacker can learn your password.
Public key authentication solves this problem. You generate a key pair, consisting of a public key (which everybody is allowed to know) and a private key (which you keep secret and do not give to anybody). The private key is able to generate signatures. A signature created using your private key cannot be forged by anybody who does not have a copy of that private key; but anybody who has your public key can verify that a particular signature is genuine.
So you generate a key pair on your own computer, and you copy the public key to the server. Then, when the server asks you to prove who you are, you can generate a signature using your private key. The server can verify that signature (since it has your public key) and allow you to log in. Now if the server is hacked or spoofed, the attacker does not gain your private key or password; they only gain one signature. And signatures cannot be re-used, so they have gained nothing.
There is a problem with this: if your private key is stored unprotected on your own computer, then anybody who gains access to your computer will be able to generate signatures as if they were you. So they will be able to log in to your server under your account. For this reason, your private key is usually encrypted when it is stored on your local machine, using a passphrase of your choice. In order to generate a signature, you must decrypt the key, so you have to type your passphrase. References:
RFC 2409: The Internet Key Exchange (IKE); DORASWAMY, Naganand & HARKINS, Dan Ipsec: The New Security Standard for the Internet, Intranets, and Virtual Private Networks, 1999, Prentice Hall PTR; SMITH, Richard E. Internet Cryptography, 1997, Addison-Wesley Pub Co.; HARRIS, Shon, All-In-One CISSP Certification Exam Guide, 2001, McGraw-Hill/Osborne, page 467. http://en.wikipedia.org/wiki/Pre-shared_key http://www.home.umk.pl/~mgw/LDAP/RS.C4.JUN.97.pdf http://the.earth.li/~sgtatham/putty/0.55/htmldoc/Chapter8.html#S8.1