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Password Management

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Password Mana Management gement


Password Management  •

Password Protection:  The front line of defense against intruders is the password system. Virtually all multiuser systems require that a user provide not only a name or identier (ID) ut serves also to a authenti!ate password. The password the ID of the individual logging on to the system. In turn" the ID provides se!urity in the following ways#


 The ID determines whether the user is authori$ed to gain a!!ess to a system.

 The ID determines the privileges a!!orded to the user.


The Vulnerability of Passwords: let us !onsider a s!heme that is widely used on %&I'# a!h user sele!ts a password up to eight  –

!hara!ters.  This is !onverted into a *+it value (,ey input to an en!ryption en !ryption routine).  The en!ryption routine is ased on D-.  The D- algorithm is modied using a



/+it.  This value is related to the time at whi!h








 The modied modi ed D- algorithm iis s e0er!ised e0er!ised with a data input !onsisting of a *1+it lo!, of $eros.  The output of the algorithm then serves as input for a se!ond en!ryption.  This pro!ess is repeated for a total of / en!ryptions.  The resulting *1+it output is then translated into an +!hara!ter sequen!e.  The hashed password is then stored" together with a plainte0t !opy of the salt" in the password le


The salt serves three purposes: It prevents dupli!ate passwords  –


from eing visile in the password le. It e2e!tively in!reases the length of the password without requiring the user to rememer additional !hara!ters.


Access Control: 3ne way to thwart a password atta!, is to deny the opponent a!!ess to the password le. If the en!rypted password portion of the le is a!!essile only y a privileged user" itthen the opponent !annot read without already ,nowing the password of a privileged privile ged user user..


Password Selection Strategies: Password  The goal is to eliminate guessale passwords while allowing the user to sele!t a password that is memorale. 4our asi! tte!hniques e!hniques are in use#  –



%ser edu!ation. 5omputer+generated passwords. 6ea!tive password !he!,ing.


Proa!tive password !he!,ing.


User education %sers !an e told the importan!e of using hard+to+guess passwords and !an e provided with guidelines for sele!ting strong passwords. Computergenerated passwords  –


passwords are quite random in nature !eactive password chec"ing the system periodi!ally runs its own password !ra!,er to nd guessale  –

passwords. The system !an!els any passwords that are guessed


Proactive password chec"ing user is allowed to sele!t his or her own password. 7owever" at the time of sele!tion" the system !he!,s to see if the password is allowale and" if not" re8e!ts it.  –

 The tri!, with a proa!tive password !he!,er is to stri,e a alan!e etween


user a!!eptaility and stre strength. ngth.


Proactive password chec"ing approaches: 6ule enfor!ement#  –

9ll passwords must e at least eight !hara!ters long.  The passwords must in!lude at least one ea!h of upper!ase" lower!ase" numeri! digits" and pun!tuation mar,s.


9nother possile pro!edure is simply to !ompile a large di!tionary of possile :ad: passwords.


Proactive password chec"er techni#ues Mar,ov model# generation of guessale passwords" this model shows a language !onsisting of an alphaet of three !hara!ters. The state of the system at  –

any time is the identity of the most re!ent letter. The value on the transition from one state to another represents the proaility that one letter follows another. Thus" the proaility that the

ne0t letter is " given that the !urrent


$ow to Choose a secure password% •

Do &3T use words or phrases that have personal signi!an!e. Mi0 letters" numers and symols" and use !ase sensitivity  Try to memori$e the password" and avoid writing it  Try down Do not use the same password for everything

%se a password manager (PM). your It is passwords a utility that !reates an en!rypted le where are stored.  Try  T ry to use :nonsense words.: Do not tell anyody your password.

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