Rainbow table reduction function

In summary, the conversation discusses personal research on creating functions based on sine and cosine in order to obtain a seed for pseudo-random numbers. However, it is argued that sine may not be the best function for this purpose due to its non-linear and smooth nature, which can result in disproportionate changes in output for small changes in input. It is also mentioned that it would be helpful to have someone debunk or confirm these assumptions.
  • #1
fedaykin
138
3
I recently did some personal research into the aforementioned functions.

I created a few simple functions based in part on sine (and cosine).
Anyway, the basic idea was to get a seed from the sine of some number, since -1 =< sin N =< 1.

However, I think that sine is not an ideal function to get a pseudo-random seed (assuming a pseudo-random input). If f(x) = sin x, then f'(x) = cos x.

Since the derivative is non-linear, and sine is a smooth function (and also non-linear), then there is a greater chance of picking picking some numbers relative to others.

EX: for some interval of the function, a small change in x will result in a disproportionate change in f(x) relative to a different interval.
I would be overjoyed if someone could debunk or backup my assumptions.
 
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  • #2
Since cos(x) is smooth, a small change in x may result in only a small change in sin(x), yes.
 

FAQ: Rainbow table reduction function

1. What is a rainbow table reduction function?

A rainbow table reduction function is a mathematical algorithm used in cryptography to reduce the size and complexity of a large set of precomputed hash values. It is used in conjunction with a rainbow table, which is a precomputed table containing a large number of possible plaintext and corresponding hash values. The reduction function maps the precomputed hash values to a smaller set, making it easier and faster to search for a specific plaintext value that corresponds to a given hash.

2. How does a rainbow table reduction function work?

A rainbow table reduction function works by taking a precomputed hash value from a rainbow table and applying a mathematical algorithm to it. The output of the algorithm is then used as a seed to generate a smaller set of possible plaintext values. This process is repeated multiple times until a smaller set of possible plaintext and corresponding hash values is obtained. This makes it easier to search for a specific plaintext value that corresponds to a given hash.

3. Can rainbow table reduction functions be reversed?

No, rainbow table reduction functions cannot be reversed. They are one-way functions, meaning that it is computationally infeasible to determine the original input from the output. This is an important characteristic in cryptography, as it ensures the security of the data being encrypted.

4. What are the advantages of using rainbow table reduction functions?

One advantage of using rainbow table reduction functions is that they significantly reduce the size and complexity of a large set of precomputed hash values. This makes it easier and faster to search for a specific plaintext value that corresponds to a given hash. Additionally, rainbow tables and reduction functions can be used to crack weak passwords, making them useful tools for security testing.

5. Are there any limitations to using rainbow table reduction functions?

Yes, there are some limitations to using rainbow table reduction functions. One limitation is that they are only effective against weak passwords that can be easily cracked using a brute force attack. Strong and complex passwords are not vulnerable to rainbow table attacks. Additionally, rainbow tables and reduction functions can be time-consuming and resource-intensive to create, making them less practical for everyday use.

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