(PowerShell) RSA Signature/Verify with .key and .cer

See more RSA Examples

Demonstrates how to use a .key file (private key) and digital certificate (.cer, public key) to create and verify an RSA signature.

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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.

$privKey = New-Object Chilkat.PrivateKey

# Load the private key from an RSA .key file:
$success = $privKey.LoadPemFile("privateKey.key")
if ($success -ne $true) {
    $($privKey.LastErrorText)
    exit
}

# Get the private key in XML format:
$privKeyXml = $privKey.GetXml()

$rsa = New-Object Chilkat.Rsa

# Import the private key into the RSA component:
$success = $rsa.ImportPrivateKey($privKeyXml)
if ($success -ne $true) {
    $($rsa.LastErrorText)
    exit
}

# Create the signature as a hex string:
$rsa.EncodingMode = "hex"

$strData = "This is the string to be signed."

# Sign the string using the sha-1 hash algorithm.
# Other valid choices are "md2", "sha256", "sha384",
# "sha512", and "md5".
$hexSig = $rsa.SignStringENC($strData,"sha-1")

$($hexSig)

# Load a digital certificate from a .cer file:
$cert = New-Object Chilkat.Cert

$success = $cert.LoadFromFile("myCert.cer")
if ($success -ne $true) {
    $($cert.LastErrorText)
    exit
}

$pubKey = $cert.ExportPublicKey()

# Now verify using a separate instance of the RSA object:
$rsa2 = New-Object Chilkat.Rsa

# Import the public key into the RSA object:
$success = $rsa2.ImportPublicKey($pubKey.GetXml())
if ($success -ne $true) {
    $($rsa2.LastErrorText)
    exit
}

# The signature is a hex string, so make sure the EncodingMode is correct:
$rsa2.EncodingMode = "hex"

# Verify the signature:
$success = $rsa2.VerifyStringENC($strData,"sha-1",$hexSig)
if ($success -ne $true) {
    $($rsa2.LastErrorText)
    exit
}

$("Success.")