The SHA-256 hashing algorithm is currently one of the most widely used hashing algorithm as it hasn’t been cracked yet and the hashes are calculated quickly in comparison to the other secure hashes like the SHA-512. The output from every round acts as an input for the next round and this process keeps on continuing till the last bits of the message remains and the result of the last round for the nᵗʰ part of the message block will give us the result i.e. These are the functions that are performed in each of the 64 rounds that are performed over and over for ‘n’ number of times 5. In the image above we can see exactly what happens in each round and now that we have the values and formulas for each of the functions carried out we can perform the entire hashing process. There are more 64 values that need to be kept in mind which will act as keys and are denoted by the word ‘k’. Keep these values in the back of your mind for a while, in the next step everything will be clearly understandable to you. ![]() Before we begin with that I should tell you that we need certain default values to be initialized for the steps that we are going to perform. We have our message block on which we will begin to carry out our computations to figure out the final hash. The message we obtain we append those length to the padded bits and we get the entire message block, which must be a multiple of 512. We know that we need to add 64 more bits, the way to calculate these 64 bits is by calculating the modulo of the original message i.e. Now that we have appended our padding bits to the original message we can further go ahead append our length bits which is equivalent to 64 bits, to the overall message to make the entire thing an exact multiple of 512. If you want you can have a look at my article explaining SHA-512 in detail here. Understanding SHA-256 algorithm will be extremely easy if you know the SHA-512 algorithm already, as there is mere changes in the length of bits here and there as the overall process is the same. This is the fourth part of the series where I break down, SHA-256 algorithm. Till now the articles i have written in this series are as following. ![]() So, few of you who might be following me for some time now must be knowing that this month I have dedicated to writing articles that are purely focused on doing intricate analysis of how the most well known hashing algorithms function and what makes one more complex than the other. Well let’s not dwell into that and get started with the new article. I am keeping my articles free for everyone to read as I believe in the “knowledge should be free” motto. It is always nice to see your work being recognized and appreciated. Good news folks the article that I wrote on Breaking down: SHA-1 Algorithm has been published on PenTest Magazine’s blog. Looking under the hood and understanding how it works? If you want to get the string of your hash, you should convert using the String(format:) initializer, like this: let hashString = pactMap. Obviously if you have an instance of Data you want to hash, you can put that directly into SHA256.hash(data:). For example, if you wanted to calculate the SHA-256 hash of your data you’d use this: let hashed = SHA256.hash(data: inputData)įinally, you can print out the textual representation of the hash – what we’d considered the user-facing hash string itself – like this: print(scription) You then call the hash(data:) method of whichever kind of hash you want: SHA-256, SHA-384, or SHA-512. If you want to calculate the hash value of a string you need to convert it to an instance of Data like this: let inputString = "Hello, world!" IOS 13 introduced a new framework called CryptoKit, which adds important cryptographic functionality such as encryption and hashing. How to calculate the SHA hash of a String or Data instance
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