what is the use of salt specifically the word "perturb" [closed] - unix

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
This question does not appear to be about programming within the scope defined in the help center.
Closed 9 years ago.
Improve this question
While developing a brute force based cracking algorithm for unix password I met with this line: "salt is a two-character string chosen from the set [a-zA-Z0-9./]. This string is used to perturb the algorithm in one of 4096 different ways."
I did not get 4096 ways?? 2^12 but how??

The set [a-zA-Z0-9./] is made up of 64 characters. Selecting two characters each from the full 64 character set gives 64 * 64 possibilities, or 4096.

Related

How do I interpret n raise to decimal power? [closed]

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
This question does not appear to be about programming within the scope defined in the help center.
Closed 6 years ago.
Improve this question
I want to understand the physical significance of n raise to some decimal power.
Like when i say 2^5. I understand that it means 2 multiplied 5 times. But how do i analyse 2^0.1.
Please suggest.
2^0.1 is the tenth root of 2. For rational powers, x^(p/q)=(x^p)^(1/q) is a combination of powers and roots.
For general real numbers,
x^y = exp(log(x)*y).

Hex - how many in the series 000 through to FFF? [closed]

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
This question appears to be off-topic because it lacks sufficient information to diagnose the problem. Describe your problem in more detail or include a minimal example in the question itself.
Closed 9 years ago.
Improve this question
I am trying to find out how many combinations are possible for 000 through to FFF under hex format? thanks
There are 16 choices for each of the 3 digits, so:
16*16*16 = 4096

Hash Code of a Random Number [closed]

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
Questions asking for code must demonstrate a minimal understanding of the problem being solved. Include attempted solutions, why they didn't work, and the expected results. See also: Stack Overflow question checklist
Closed 9 years ago.
Improve this question
I have a random number sequence (say 6 bytes)
I now want to generate a shorter sequence from the original sequence (say 3 bytes)
What is the best way of acheiving this so that the randomness of the original sequence is preserved.
Lets say I run a SHA-1 hash code on the original sequence and then grab some bytes from the hashed output. Does the randomness decrease, increase, or stay the same.
The basic question is - Does a Hash Code of a random number produce less random, more random or same randomness.

How do you calculate integers overflow? [closed]

Closed. This question needs details or clarity. It is not currently accepting answers.
Want to improve this question? Add details and clarify the problem by editing this post.
Closed 8 years ago.
Improve this question
I try to calculate, based on given parameters, integer overflow.
for example, if I have an integer than is <= 200, but when I insert it to an unsigned int, it will be > 200. What is the actual arithmetic process for that?
Operations on fixed size integers are usually made modulo 2m, where m is the number of bits (nowadays usually 32 or 64).
This means that a multiple of 2m is added or subtracted from the result to keep it in the range for the type, be it unsigned (0, 2m-1) or signed (-2m-1, 2m-1-1).
You might be interested in the Mathematical foundations of computer integers.

How do we get the remainder in division arithmetic for computer architecture? [closed]

Closed. This question is off-topic. It is not currently accepting answers.
Want to improve this question? Update the question so it's on-topic for Stack Overflow.
Closed 10 years ago.
Improve this question
I am learning binary division following the step-by-step procedure. I am stuck at Step One Repeat One in the remainder section. To get the remainder, the formula is Remainder = Remainder - Divisor.
How do we get to remainder: 11100110? I just don't understand how we have 1110 on the left half of the register. Any guides or help would greatly be appreciated!
Thanks:
The example is 10/5 using an 8 bit ALU.
I have attached a picture of the example for reference

Resources