PowerShell

Duplicate .NET's Rfc2898DeriveBytes Functionality

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Demonstrates how to duplicate the results produced by .NET's System.Security.Cryptography.Rfc2898DeriveBytes class. PowerShell

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

# This example assumes Chilkat Crypt2 to have been previously unlocked.
# See Unlock Crypt2 for sample code.

# This example demonstrates how to duplicate the results produced
# by .NET's System.Security.Cryptography.Rfc2898DeriveBytes class.

# For example, here is C# code that transforms a password string into
# bytes that can be used as a secret key for symmetric encryption (such as AES, blowfish, 3DES, etc.)
# 
#     Rfc2898DeriveBytes deriveBytes = new Rfc2898DeriveBytes("secret", System.Text.Encoding.UTF8.GetBytes("saltsalt123"), numIterations);
#     byte[] secretKeyBytes = deriveBytes.GetBytes(numBytes);

# (The Rfc2898DeriveBytes computation is really just the PBKDF2 algorithm with SHA-1 hashing.)
# In Chilkat, this is what we do to match...

# First, let's get a test vector with known results.  Both Chilkat AND Microsoft should produce
# the same results.  RFC 6070 has some PBKDF2 HMAC-SHA1 Test Vectors.  Here is one of them:

#      Input:
#        P = "passwordPASSWORDpassword" (24 octets)
#        S = "saltSALTsaltSALTsaltSALTsaltSALTsalt" (36 octets)
#        c = 4096
#        dkLen = 25
# 
#      Output:
#        DK = 3d 2e ec 4f e4 1c 84 9b
#             80 c8 d8 36 62 c0 e4 4a
#             8b 29 1a 96 4c f2 f0 70
#             38                      (25 octets)
# 
# 

$crypt = New-Object Chilkat.Crypt2

$salt = "saltSALTsaltSALTsaltSALTsaltSALTsalt"
# Given that the salt is really binary data (can be any random bunch of bytes),
# we must pass the exact hex string representation of the salt bytes.
# In this case, we're getting the utf-8 byte representation of our salt string,
# which is identical to the us-ascii byte representation because there are no 8bit chars..
$saltHex = $crypt.EncodeString($salt,"utf-8","hex")

# Duplicate the test vector as shown above.
$dkHex = $crypt.Pbkdf2("passwordPASSWORDpassword","utf-8","sha1",$saltHex,4096,25 * 8,"hex")
$($dkHex)