(PowerShell) RSA Sign utf-8 Bytes of String to get Base64 RSA Signature

See more Apple Keychain Examples

Demonstrates how RSA sign the utf-8 byte representation of a string to get the signature in base64 format.

Chilkat .NET Downloads Chilkat .NET Assemblies

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

# Assuming the smartcard/USB token is installed with the correct drivers from the manufacturer,
# this code can work on multiple platforms including Windows, MacOS, Linux, and iOS.

# Chilkat automatically detects and determines the way in which the HSM is used,
# which can be by PKCS11, Apple Keychain, Microsoft CNG / Crypto API, or ScMinidriver.

$cert = New-Object Chilkat.Cert

# Set the token/smartcard PIN prior to loading.
$cert.SmartCardPin = "123456"

# Specify the certificate by its common name.
$success = $cert.LoadFromSmartcard("cn=chilkat-rsa-2048")
if ($success -eq $false) {
    $($cert.LastErrorText)
    exit
}

$("Signing with cert: " + $cert.SubjectCN)

# Create a string to be hashed and signed.
$sb = New-Object Chilkat.StringBuilder
$crlfLineEnding = $true

for ($i = 0; $i -le 10; $i++) {
    $sb.AppendLine("This is a test.",$crlfLineEnding)
}

$rsa = New-Object Chilkat.Rsa

# Use the certificate's private key for signing.
$success = $rsa.SetX509Cert($cert,$true)
if ($success -eq $false) {
    $($rsa.LastErrorText)
    exit
}

# Sign the SHA-256 hash of the utf-8 byte representation of the contents of sb
# Return the signature in base64 format.
$rsa.EncodingMode = "base64"
$rsa.Charset = "utf-8"
$stringToSign = $sb.GetAsString()
$sigBase64 = $rsa.SignStringENC($stringToSign,"sha256")
if ($rsa.LastMethodSuccess -eq $false) {
    $($rsa.LastErrorText)
    exit
}

$("RSA signature as base64: " + $sigBase64)