uCertify Articles » 312-50 http://www.ucertify.com/article Just another WordPress weblog Wed, 04 Nov 2009 00:00:00 +0000 http://wordpress.org/?v=2.8.4 en hourly 1 What is AutoFill? http://www.ucertify.com/article/what-is-autofill-2.html http://www.ucertify.com/article/what-is-autofill-2.html#comments Tue, 29 Sep 2009 00:00:00 +0000 uCertify 3601182

The AutoFill feature of a browser automatically fills the text in the text box as the user types. It does not suggest any options as done by the AutoComplete feature. The AutoFill feature can be set by the user of the browser and not by the author of the Web site.

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The chage command is used for changing user password expiry information.

Syntax:

chage [-m mindays] [-M maxdays] [-d lastday] [-E expireday] [-I inactive] [-W warndays] [-l] user

The functions of the switches are as follows:

Switch Meaning
-m Minimum number of days between each successive password change.
-M Maximum number of days during which a password remains valid.
-d Number of days since January 1st, 1970 when a password was last changed.
-E The date on which the user account will no longer be accessible.
-I Number of days since the expiry of a user password when an account is locked.
-W Number of days of warning before a password change is required.
-l Used by a non-administrative user to check his account/password expiry status.
Share/Bookmark]]> http://www.ucertify.com/article/what-is-chage-command-2.html/feed 0 What is Diffie-Hellman encryption? http://www.ucertify.com/article/what-is-diffie-hellman-encryption-2.html http://www.ucertify.com/article/what-is-diffie-hellman-encryption-2.html#comments Fri, 28 Aug 2009 00:00:00 +0000 uCertify 1401388

The Diffie-Hellman encryption was developed by Diffie and Hellman in 1976 and published in the paper named “New Directions in Cryptography.” It is a key agreement protocol (also called exponential key agreement) that allows two users to exchange a secret key over an insecure medium (such as the Internet) without any prior secrets. The original protocol had two system parameters, p and g. They are both public and may be used by all the users in a system. The Diffie-Hellman key exchange was vulnerable to a man-in-the-middle attack, as Diffie-Hellman key exchange does not authenticate the participants.

The current form of the Diffie-Hellman protocol (also known as authenticated Diffie-Hellman key agreement protocol, or Station-to-Station (STS) protocol), was developed by Diffie, Van Oorschot, and Wiener in 1992 to overcome the man-in-the-middle attack. This is achieved by allowing the two parties to authenticate themselves to each other by the use of digital signatures and public-key certificates. The Diffie-Hellman protocol is an example of a much more general cryptographic technique, the common element being the derivation of a shared secret value (that is, key) from one party’s public key and another party’s private key. The parties’ key pairs may be generated anew at each run of the protocol as in the original Diffie-Hellman protocol. The public keys may be certified so that the parties can be authenticated and there may be a combination of these attributes.

Share/Bookmark]]> http://www.ucertify.com/article/what-is-diffie-hellman-encryption-2.html/feed 0 What is ad hoc network? http://www.ucertify.com/article/what-is-ad-hoc-network-2.html http://www.ucertify.com/article/what-is-ad-hoc-network-2.html#comments Thu, 27 Aug 2009 00:00:00 +0000 uCertify 1401340

Ad hoc is a basic topology of a wireless network. An ad hoc network consists of two or more wireless devices that communicate directly with each other. The wireless local area network (WLAN) network interface adapters in the wireless devices generate omni directional signals within a limited range called basic service area (BSA). When two wireless devices come within the range of each other, they immediately form a two-node network and are able to communicate with each other.

An ad hoc network is non-transitive.

Share/Bookmark]]> http://www.ucertify.com/article/what-is-ad-hoc-network-2.html/feed 0 What is Trojan horse? http://www.ucertify.com/article/what-is-trojan-horse-2.html http://www.ucertify.com/article/what-is-trojan-horse-2.html#comments Wed, 19 Aug 2009 00:00:00 +0000 uCertify 1301109

Trojan horse is a malicious software program code that masquerades itself as a normal program. When a Trojan horse program is run, its hidden code runs to destroy or scramble data on the hard disk. An example of a Trojan horse is a program that masquerades as a computer logon to retrieve user names and password information. The developer of a Trojan horse can use this information later to gain unauthorized access to computers. Trojan horses are normally spread by e-mail attachments. Unlike viruses, Trojan horses do not replicate themselves but only destroy information on hard disks.

Share/Bookmark]]> http://www.ucertify.com/article/what-is-trojan-horse-2.html/feed 0 What is dictionary attack? http://www.ucertify.com/article/what-is-dictionary-attack-2.html http://www.ucertify.com/article/what-is-dictionary-attack-2.html#comments Wed, 19 Aug 2009 00:00:00 +0000 uCertify 1301124

Dictionary attack is a type of password guessing attack. This type of attack uses a dictionary of common words to find out the password of a user. It can also use common words in either upper or lower case to find a password. There are many programs available on the Internet to automate and execute dictionary attacks.

Share/Bookmark]]> http://www.ucertify.com/article/what-is-dictionary-attack-2.html/feed 0 What is WTLS? http://www.ucertify.com/article/what-is-wtls-2.html http://www.ucertify.com/article/what-is-wtls-2.html#comments Wed, 19 Aug 2009 00:00:00 +0000 uCertify 1301132

Wireless Transport Layer Security (WTLS) is a security layer of WAP, which is specifically designed for a wireless environment. It provides privacy, data integrity, and authentication for client-server communications over a wireless network. WTLS ensures that a client and server are authenticated so that wireless transactions remain secure and the connection is encrypted. WTLS is required because a wireless network does not provide end-to-end security.

Share/Bookmark]]> http://www.ucertify.com/article/what-is-wtls-2.html/feed 0 What is AutoFill? http://www.ucertify.com/article/what-is-autofill.html http://www.ucertify.com/article/what-is-autofill.html#comments Mon, 03 Aug 2009 00:00:00 +0000 uCertify 3601182

The AutoFill feature of a browser automatically fills the text in the text box as the user types. It does not suggest any options as done by the AutoComplete feature. The AutoFill feature can be set by the user of the browser and not by the author of the Web site.

Share/Bookmark]]> http://www.ucertify.com/article/what-is-autofill.html/feed 0 What is the Triple Data Encryption Algorithm (TDEA)? http://www.ucertify.com/article/what-is-the-triple-data-encryption-algorithm-tdea.html http://www.ucertify.com/article/what-is-the-triple-data-encryption-algorithm-tdea.html#comments Sun, 02 Aug 2009 00:00:00 +0000 uCertify 4301025

The Triple Data Encryption Algorithm (TDEA) was proposed by Tuchman and first came into existence in functional applications in 1985. The Triple DEA algorithm uses three keys and executes the DES algorithm three times. It follows an encrypt-decrypt-encrypt (EDE) sequence as follows:

C = Ek3 [ Dk2 [ Ek1 [P] ] ]
Where
C = Cipher Text
P = Plain Text
Ek [X] = encryption of X using key K.
Dk [Y] = decryption of Y using key K.

Share/Bookmark]]> http://www.ucertify.com/article/what-is-the-triple-data-encryption-algorithm-tdea.html/feed 0 What is chage command? http://www.ucertify.com/article/what-is-chage-command.html http://www.ucertify.com/article/what-is-chage-command.html#comments Fri, 17 Jul 2009 00:00:00 +0000 uCertify 2201121

The chage command is used for changing user password expiry information.

Syntax:

chage [-m mindays] [-M maxdays] [-d lastday] [-E expireday] [-I inactive] [-W warndays] [-l] user

The functions of the switches are as follows:

Switch Meaning
-m Minimum number of days between each successive password change.
-M Maximum number of days during which a password remains valid.
-d Number of days since January 1st, 1970 when a password was last changed.
-E The date on which the user account will no longer be accessible.
-I Number of days since the expiry of a user password when an account is locked.
-W Number of days of warning before a password change is required.
-l Used by a non-administrative user to check his account/password expiry status.
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