What is a reverse lookup table?

What is a reverse lookup table?

Using Reverse Lookup Tables, you create a lookup table consisting of the password hash of user accounts. Then you use another table which consists of hashes with guessed passwords. Then you compare the two to see if the hashed password of compromised user account matches hashed password in lookup table.

What is the significance of reverse lookup table for attacker?

By hashing the password on the client before it is transmitted and enforcing a strong password policy will protect against brute-force attacks against a single user.

Why use look up tables instead of gates?

The LUT can implement any function of its inputs, and it’s reloadable. Traditional logic gates can do only one job for which it was built. FPGA must be able to freely reconfigure its cells, and you want all the flexibility you can get. And LUT is the way to have it.

What is Rainbow tables in cryptography?

Rainbow tables are tables of reversed hashes used to crack password hashes. Computer systems requiring passwords typically store the passwords as a hash value of the user’s password. When a computer user enters a password, the system hashes the password and compares it to the stored hash.

What is the difference between FPGA and CPLD?

FPGA contains up to 100,000 of tiny logic blocks while CPLD contains only a few blocks of logic that reaches up to a few thousands. 2. In terms of architecture, FPGAs are considered as ‘fine-grain’ devices while CPLDs are ‘coarse-grain’. FPGA is a RAM-based digital logic chip while CPLD is EEPROM-based.

What is a slice in FPGA?

A slice contains a set number of LUTs, flip-flops and multiplexers. A LUT is a collection of logic gates hard-wired on the FPGA. For example, a slice on a Virtex-II FPGA has two LUTs and two flip-flops but a slice on a Virtex-5 FPGA has four LUTs and four flip-flops.

Can you lookup a number to see who it is?

Can you Google search a phone number? Using Google, type the phone number in the search field with the numbers separated by hyphens (for example, 012-555-6789). Hit enter and you’ll see results showing the phone owner’s name and address.

How does reverse lookup table work in SQL?

The idea is that you create a table storing what you enter as input and the hash it generates. After you run your routine with as many inputs you think are valid, you can then attack the password file with a reverse lookup table: you browse your database browsing not by the password but for what Hash matches.

Which is an example of a reverse lookup?

Reverse lookup then, is simply not looking by the same input, but for inputs which generate the same output. For example: Instead of looking for the admin string, in your table you would be looking by the string which matches the hash 21232f297a57a5a743894a0e4a801fc3.

How does reverse lookup table attack password file?

After you run your routine with as many inputs you think are valid, you can then attack the password file with a reverse lookup table: you browse your database browsing not by the password but for what Hash matches. Reverse lookup then, is simply not looking by the same input, but for inputs which generate the same output.

Why are rainbow tables better than lookup tables?

Rainbow tables are a time-memory trade-off technique. They are like lookup tables, except that they sacrifice hash cracking speed to make the lookup tables smaller. Because they are smaller, the solutions to more hashes can be stored in the same amount of space, making them more effective.