For our Theory of Algorithms project we have been tasked with writing a program in the C programming language to calculate the SHA512 value of an input file. The program also must incorporate command line arguments to receive the file location. The use of any external libraries is prohibited and we are strictly only allowed to use the C standard library.
- First you will need to have a Ubuntu or Debian subsystem installed to run the code through the windows terminal. You can find resources to download from the link below. Ubuntu Subsystem
- Once you have your subsystem installed, you should clone this repository.
git clone https://github.com/Moran98/TOA
NOTE: Make sure that you are using the Ubuntu terminal through the Windows Terminal before compiling or running the code.
- To compile the code use the following command inside of the 'TOA' directory:
gcc -o sha512 sha512.c
- Once the code has been compiled run the command to execute the file:
./sha512 input.txt
- SHA is as acronym for Secure Hash Algorithm, the result of the algorithm hashing a piece of data cannot be duplicated, it is usually known as one way encryption. Although it is not exactly an encryption algorithm it is more considered a cryptographic hash algorithm. Hash algorithms can take a large bundle of text and convert it into a single hashed string. For example the below sentance is converted using the SHA-512 algorithm to receive the output of a hashed string.
Mary and Samantha arrived at the bus station early but waited until noon for the bus.
6ed657baaddac9006469da76980926fa83d269b59c37547846563db003486a6664557bd530c89b5650d8754a1a67247263cc948ff8326cdd3a35a48e5539a904
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The SHA-512 algorithm guarantees that no other string message can generate the same hashed output. This acts almost like a signature or a finger print for the inputed string.
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The SHA-512 algorithm is extremely important as its used for protecting our digital passwords and email address hashing. The SHA-512 algirthm is still used within industry but has become less popular as bcrypt is now widely used within most web applications that require login details. This does not make the SHA-512 algorithm any less secure than before, but its main purpose is to be used as a cryptographic hash function.
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The SHA-512 algorithm is a hashing algorithm that performs a hashing function depending on the input data that it receives. Hashing Algorithms have become extremely important and common in regards to digital and online security standards. Its primarily used within the Blockchain. SHA-512 uses 1024 bit blocks and the maximum input string it can accept is 2^128 bits. SHA-512 is very similar in structure to its counterpart SHA-256 but instead the input is broken into 1024 bits and its initial hash values are extended to 64 bits.
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Facebook are currently using the SHA-256 as their algorithm to encrypt passwords and user data to protect their massive database from being targeted by hackers, all user information that is sent back to the Facebook servers is encrypted using the hashing algorithm. SHA-256 has been used within Bitcoin since the very beginning of the cryptocurrency era, its main purpose is to create the bitcoin addresses to send and receive crypto.
The SHA-512 takes a few simple steps to complete its cycle, they are as follows:
- Input Format
- Hash Buffer
- Message Processing
- Output Result
We cannot reverse the SHA512 algortihm due to bit dependency. The reason as to why we cannot retrieve the original message from a hash digest is because it has been constructed to make sure that each bit from the output matches the bit from the input. Since the algorithm has been designed this way it prevents people from reverse engineering the algorithm. To be able to calculate a single output bit you must have knowledge of the contents within the input file.
Q. Can you design an algorithm that, given enough time, will find input messages that give each of the possible 512-bit strings?
Yes, it is possible given enough time the algorithm will be capable of with any given any sort of input to receiving the same hash output value. It can be cracked through brute force although this would take a significant amount of time as a computer with a high processing power is required. Although the 'trial and error' technique is not efficient as you're guessing over and over until you finally guess correctly. This is why slowing down the hashing process will slow down the hacker trying to access hashed passwords.
Due to the SHA-512 algorithm being a one-way function, this makes it difficult to get a hash digest with twelve zeros as you will need to use brute force to get the desired output. Firstly you will need to find the target value which in our case will be with twelve zeros :
target = 000000000000fffffffffffffffffffffffffffffffffffffffffffffffffffffff
Then you must divide it by the maximum 512 bit integer which is:
max = FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
Calculating this will then give us the probablity of a single hash:
target / max = 1.25673... ×10^-88
Then we need to calculate the amount of hashes to solve a block:
1/1.25673×10^-88 = 7.9571718e-89
or
79.5 Billion.
We are then dividing the value by the hashrate of our computer which is typically around 100,000 Hash/second.
7.95e10 / 100,000 = 795,000 seconds
- Ian McLoughlin - Lecturer, GMIT.
- Secure Hash Standard
- Git Handbook
- Secure Hash Algorithms
- Mining Bitcoin with pencil and paper: 0.67 hashes per day
- Visual Studio Code.
- Ubuntu Subsystem.