I would like to have a hashing algorithm, that can generate a hash string but with alphanumeric characters but under a specified limit.
For example, If I provide it some text, it should generate a string that can be used as a password for websites. So at least 8 characters long, must contain at least a capital letter and at least a number.
Is there any hash algorithm like this? or would I have to create a custom implementation? or is it not possible at all?
I'd like to do this in javascript
So at least 8 characters long, must contain at least a capital letter and at least a number
Generate a random integer that determines the number of capitals, Use getRandomInt from this answer that uses sampling with rejecting. This uses the getRandomValues to get cryptographically strong random values.
let capNum = getRandomInt(1,7)
One reserved for digits
Generate the number of digits.
let digNum = getRandomInt(1, 8-capNum)
Now we have 8 - capnum - digNum amount letters ( not capitals)
Generate necessary random elements for each group and store all of them into a string arr.
Apply Fisher–Yates shuffle algorithm so that the order of the characters in the string shuffles.
var i = arr.length, k , temp;
while(--i > 0){
k = getRandomInt(0, i);
/swap
temp = arr[k];
arr[k] = arr[i];
arr[i] = temp;
}
a = getRandomInt(0,9) for a letter a = getRandomInt(0,26) then convert integer to letter...I didn't say in which language you need the algorithm .
In CSharp:
public static string Hash(string password)
{
var bytes = System.Text.Encoding.UTF8.GetBytes(password);
using var hash = System.Security.Cryptography.SHA512.Create();
{
var hashedInputBytes = hash.ComputeHash(bytes);
// Convert to text
// StringBuilder Capacity is 128, because 512 bits / 8 bits in byte * 2 symbols for byte
var hashedInputStringBuilder = new System.Text.StringBuilder(128);
foreach (var b in hashedInputBytes)
hashedInputStringBuilder.Append(b.ToString("X2"));
return hashedInputStringBuilder.ToString();
}
}
