PowerShell Requires Chilkat v11.0.0+

Verify an RSA Signature Against the Signed Hash

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Demonstrates how to validate an RSA Signature against the hash that was signed. PowerShell

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

$success = $false

$bd = New-Object Chilkat.BinData

for ($i = 0; $i -le 100; $i++) {
    $bd.AppendEncoded("000102030405060708090A0B0C0D0E0F","hex")
}

$sha256_base64 = $bd.GetHash("sha256","base64")
$("sha256 hash in base64 format: " + $sha256_base64)

$base64_rsa_sig = "AwF2BbOvL6jA5DwmMAc9n6J2Cc8PI6Rj5W079+aKJcIEtPWRzHor0Bvc3aftGM3Jbgj6SXlIC3M3RYS7UZOnfiHKFNZgbxaNT5WwsWooK42ZkC8DBZl0p7OunBUKd5SciUo+TKilioeUkriN3L1Zl9hwi3HVDVqgVo3XXskwIftSqLSFlepTLTmOWj9Y93dp8J4D9RyLtNgFQBc0WB22tyJTsuY56mLcWe1AMF3LizB9OrbwjynF2u16xWlrJdugccz795fJBUV9aQSD+8S3KeqwQhoi8RK1uhD68aGCyaSpBq0NZ8COAkn7MXaF4POxrAAt8udfHM+PRfSOptcH/w=="

#  Get the public key to be used for signature verification.
$pubKey = New-Object Chilkat.PublicKey
$success = $pubKey.LoadFromFile("rsaKeys/chilkat-rsa-2048.pem")
if ($success -eq $false) {
    $($pubKey.LastErrorText)
    exit
}

$rsa = New-Object Chilkat.Rsa
$success = $rsa.UsePublicKey($pubKey)
if ($success -eq $false) {
    $($rsa.LastErrorText)
    exit
}

#  Verify the hash against the signature.
$rsa.EncodingMode = "base64"
$success = $rsa.VerifyHashENC($sha256_base64,"sha256",$base64_rsa_sig)

if ($success -eq $false) {
    $($rsa.LastErrorText)
    $("Signature invalid.")
}
else {
    $("Signature valid.")
}