PowerShell

Manually Duplicate SetSecretKeyViaPassword

Demonstrates how to duplicate the password string to binary secret key computation of SetSecretKeyViaPassword.

This is a cryptographically weak way of generating a secret key from a password. The SetSecretKeyViaPassword method is deprecated and should not be used.

PowerShell

Add-Type -Path "C:\chilkat\ChilkatDotNet47-x64\ChilkatDotNet47.dll"

# This example assumes the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

$crypt = New-Object Chilkat.Crypt2

# The password string is transformed to a binary secret key by computing the 
# MD5 digest (of the utf-8 password) to obtain 16 bytes.  
# If the KeyLength is greater than 16 bytes, then the MD5 digest of the Base64 encoding 
# of the utf-8 password is added.  A max of 32 bytes of key material is generated, and 
# this is truncated to the actual KeyLength required.

$crypt.CryptAlgorithm = "aes"
$crypt.KeyLength = 256

$password = "this is my password"
$crypt.SetSecretKeyViaPassword($password)

# Examine the resulting SecretKey in hex:
$("Computed Secret Key = " + $crypt.GetEncodedKey("hex"))

# Now perform the same computation manually:
$sb = New-Object Chilkat.StringBuilder

$crypt.HashAlgorithm = "md5"
$crypt.Charset = "utf-8"
$crypt.EncodingMode = "hex"
$sb.Append($crypt.HashStringENC($password))

$passwordBase64 = $crypt.EncodeString($password,"utf-8","base64")
$sb.Append($crypt.HashStringENC($passwordBase64))

$("Manually Computed = " + $sb.GetAsString())

# The output is:
# Computed Secret Key = 210D53992DFF432EC1B1A9698AF9DA16C7E90518F90E24828F78EC9E0A413B36
# Manually Computed = 210D53992DFF432EC1B1A9698AF9DA16C7E90518F90E24828F78EC9E0A413B36