(PowerShell) AES and CHACHA20 Encrypt/Decrypt Text

Demonstrates the use of the new EncryptSb and DecryptSb methods introduced in Chilkat v9.5.0.67 to encrypt/decrypt the contents of StringBuilder objects.

Note: This example requires Chilkat v9.5.0.67 or greater.

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Add-Type -Path "C:\chilkat\ChilkatDotNet47-9.5.0-x64\ChilkatDotNet47.dll"

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

# First build a string to be encrypted
$sb = New-Object Chilkat.StringBuilder
$i = 1
while ($i -lt 10) {
    $sb.AppendInt($i)
    $sb.Append(" the quick brown fox jumped over the lazy dog.`r`n")
    $i = $i + 1
}

$($sb.GetAsString())

# The string to be encrypted looks like this:

# 1 the quick brown fox jumped over the lazy dog.
# 2 the quick brown fox jumped over the lazy dog.
# 3 the quick brown fox jumped over the lazy dog.
# 4 the quick brown fox jumped over the lazy dog.
# 5 the quick brown fox jumped over the lazy dog.
# 6 the quick brown fox jumped over the lazy dog.
# ...

$crypt = New-Object Chilkat.Crypt2

# Specify the encryption to be used.
# First we'll do AES-128 CBC
$crypt.CryptAlgorithm = "aes"
$crypt.CipherMode = "cbc"
$crypt.KeyLength = 128

$ivHex = "000102030405060708090A0B0C0D0E0F"
$crypt.SetEncodedIV($ivHex,"hex")

$keyHex = "000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F"
$crypt.SetEncodedKey($keyHex,"hex")

# When EncryptSb is called, the contents of the source (sb)
# remains unmodified.  The encrypted bytes are written into bdEncrypted.
# If bdEncrypted already contained data, it is replaced with the encrypted bytes.
$bdEncrypted = New-Object Chilkat.BinData
$success = $crypt.EncryptSb($sb,$bdEncrypted)
if ($success -ne $true) {
    $($crypt.LastErrorText)
    exit
}

# Examine the encrypted bytes:
$($bdEncrypted.GetEncoded("base64_mime"))

# Sample encrypted data:

# 0DdNZ22ckMMJBiaKhAu3wUEfh16XW356NIUsDmNs/xwbHe/p1201OmpfzwXwKktkAefu2pckrBgC
# df+1w8lRo+KAy5n5wlAgMGM/UrsVJsp0BmDPk1vaxKrmrGpSXOVCQs1n2+0atIs5YLiOG+Va3+Mi
# EQNb4YK7bNMmvt0++irBxTiGnkx/RncfKwgkbBUpl2x7yV13MW6lapDT6Md0DKAMsTXFJYGeIdEf
# g2uxDDQzI5gUOUHTMrXQ8paD/K76KKB9Jpp/kAM9z8g/d8KUmuphA7KI64d38xsgOmcITlbhlCQ2
# PDkcU6RRzX0FUTUSMgQukhy0jkLZEjHX9poKJD+iJTOkcQUC3OqR9hKhSrvIgJN4lxdR71MheOoQ
# 2wmvRdq+agTWWh333Vmb6J6yDV79aSpnqEDrA8Ks7Xzciol0gve91+JtVJlJKjWwEzWEU8GxF7Q8
# eaWI70lsC5nTLGcbqgKu6gzkzHlHyHaE2FAQA/d5I2dvfsAYUQCza0Zdyw8mmTtHhlP2Tfxj1uPv
# H4Q7BGuKnx3SWT2CnpbX4091w7KzLAztrbFBo/Tf9w8ZpgTK9k1ryfW9/xnk6rW6iQ==

# Decrypt to restore back to the original:
$sbOriginal = New-Object Chilkat.StringBuilder
$success = $crypt.DecryptSb($bdEncrypted,$sbOriginal)
if ($success -ne $true) {
    $($crypt.LastErrorText)
    exit
}

# Examine the original data:
$($sbOriginal.GetAsString())

# ----------------------------------------------------------------------------------
# To do chacha20 encryption, just change the settings:

$crypt.CryptAlgorithm = "chacha20"
$crypt.KeyLength = 256
# The initial count is the initial block counter for the chacha20 algorithm.
# It can be any integer, but must be set to the same when decrypting.
$crypt.InitialCount = 22

# EncryptSb completely replaces the contents of bdEncrypted.
$success = $crypt.EncryptSb($sb,$bdEncrypted)

# However.. DecryptSb appends the decrypted text to whatever may
# have already existed within sbOriginal.
$success = $crypt.DecryptSb($bdEncrypted,$sbOriginal)

$("----")
$("The original data should be here twice.  Once from the AES decrypt, and again from the chacha20 decrypt.")
$($sbOriginal.GetAsString())
$("Success.")