The following is an example, written in Visual Basic, of how to compute the SHA-256 hash for the data string "myPassword" and display it in a label called Label1:
Public Class Form1
Private Function ComputeSHA256Hash(ByVal Password As String) As String
' Convert Password into a byte array.
Dim passwordBytes As Byte()
passwordBytes = Encoding.UTF8.GetBytes(Password)
' Initialize the SHA256 hashing algorithm class
Dim shaM As New SHA256Managed()
' Compute hash value of the password.
Dim hashBytes As Byte()
hashBytes = shaM.ComputeHash(passwordBytes)
' Convert hash into a base64-encoded string.
ComputeSHA256Hash = Convert.ToBase64String(hashBytes)
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Label1.Text = ComputeSHA256Hash("myPassword")End Sub
The ComputeSHA256Hash function uses the .NET Framework Class Library System.Security.Cryptography class. It takes the string Password and turns it into a byte-array. It then runs those bytes through the SHA256Managed computation function provided by the class and returns a 44-bit string of the hash that's created. It finally displays via Labe1.Text. The hash for myPassword using this program is dlSbgn7EbnBf0DgxgT+lIXIzjw38vXEe1EuBqW2sUcY=. If you change the input to mzPassword, so just one character different, the hash changes to something completely different - XkdNLN2VuBgcMjhI/Dg0ioj4Eds6FLDF3lRlBxt+I4U=.
For security reasons, if you are using hash values to store passwords, you may well want to use a salt, as this makes a hashed-password less immune to dictionary attacks. Not only would the hacker have to develop a hash for every commonly known password, but also for every commonly known password multiplied by the nearly infinite number of possible salts.
Dig deeper on Disk Encryption and File Encryption
Related Q&A from Michael Cobb
Users in the enterprise may unknowingly be exposed to 'Gchat' security risks. Expert Michael Cobb discusses Internet application security best ...continue reading
Do you know some of the best third-party patch deployment tools? See expert Michael Cobb's recommendations on which tools would work best for your ...continue reading
Today's powerful smartphones can sometimes spread viruses to the corporate network. Learn how it can happen and how to prevent it.continue reading
Have a question for an expert?
Please add a title for your question
Get answers from a TechTarget expert on whatever's puzzling you.