Like this CertiGuide? Get it in PDF format!
Click Here!
Use coupon code "certiguide" to save 20%!
(Expires 2004/12/31)

Need more practice? 300 additional Security+ questions!
Get It Here!

Custom Search







Table Of Contents  CertiGuide to Security+
 9  Chapter 4:  Basics of Cryptography (Domain 4.0; 15%)
      9  4.2  Concepts in Using Cryptography

Previous Topic/Section
4.2.1  Confidentiality
Previous Page
Pages in Current Topic/Section
1
Next Page
4.2.2.1  Digital Signatures
Next Topic/Section

4.2.2  Integrity

Integrity is the assurance that data has not been tampered with – i.e., that it has been unchanged during some period of time since it was created.

Both public/private keys and symmetrical (secret) keys are acceptable for providing confidentiality. Other methods must be employed to ensure full data integrity. Why? Anyone with access to both the key used to decrypt the message (so that they can decrypt it) and the original key used to encrypt the message (so that they can encrypt a substitute message after changing it) can tamper with a message.

In a symmetric key system, this means that anyone with access to the shared secret key can tamper with the message, and change it without being detected.

In an asymmetric key system, because the private is held by only one person (unless someone’s managed to compromise it), it is increasingly difficult to tamper with a message. Usually, if you’re able to decrypt it, because it was encrypted with a public key you have access to, you can’t encrypt it again because you don’t have access to the private key that was used to encrypt it. However, it’s possible to decrypt the message and then use a different public/private key pair to distribute it, misrepresenting that new key pair as the original sender’s key pair. This misrepresentation might involve social engineering, or replacing a user’s public key posted to their web site with the new public key, etc.

Figure 41: Notice that a public key can be used to encrypt a message that can only be open with a private key.

 


Data Integrity is…

Integrity is the assurance that the message date has not been altered since the encrypted version of the message was created.


Quick navigation to subsections and regular topics in this section



Previous Topic/Section
4.2.1  Confidentiality
Previous Page
Pages in Current Topic/Section
1
Next Page
4.2.2.1  Digital Signatures
Next Topic/Section

If you find CertiGuide.com useful, please consider making a small Paypal donation to help the site, using one of the buttons below. You can also donate a custom amount using the far right button (not less than $1 please, or PayPal gets most/all of your money!) In lieu of a larger donation, you may wish to consider buying an inexpensive PDF equivalent of the CertiGuide to Security+ from StudyExam4Less.com. (Use coupon code "certiguide" by December 31, 2004 to save 20%!) Thanks for your support!
Donate $2
Donate $5
Donate $10
Donate $20
Donate $30
Donate: $



Home - Table Of Contents - Contact Us

CertiGuide for Security+ (http://www.CertiGuide.com/secplus/) on CertiGuide.com
Version 1.0 - Version Date: November 15, 2004

Adapted with permission from a work created by Tcat Houser et al.
CertiGuide.com Version Copyright 2004 Charles M. Kozierok. All Rights Reserved.
Not responsible for any loss resulting from the use of this site.