Confirm-JsonWebSignature.ps1
|
<#
.SYNOPSIS Validate the digital signature for JSON Web Signature. .EXAMPLE PS C:\>Confirm-JsonWebSignature $Base64JwsString -SigningCertificate $SigningCertificate Validate the JWS string was signed by provided certificate. .INPUTS System.String #> function Confirm-JsonWebSignature { [CmdletBinding()] [Alias('Confirm-Jws')] [OutputType([bool])] param ( # JSON Web Signature (JWS) [Parameter(Mandatory=$true, Position=0, ValueFromPipeline=$true)] [string[]] $InputObjects, # Certificate used to sign the data [Parameter(Mandatory=$true)] [System.Security.Cryptography.X509Certificates.X509Certificate2] $SigningCertificate ) process { foreach ($InputObject in $InputObjects) { $Jws = ConvertFrom-JsonWebSignature $InputObject $JwsData = $InputObject.Substring(0,$InputObject.LastIndexOf('.')) [Security.Cryptography.HashAlgorithmName] $HashAlgorithm = [Security.Cryptography.HashAlgorithmName]::"SHA$($Jws.Header.alg.Substring(2,3))" switch ($Jws.Header.alg.Substring(0,2)) { 'RS' { $RSAKey = [System.Security.Cryptography.X509Certificates.RSACertificateExtensions]::GetRSAPublicKey($SigningCertificate) [bool] $Result = $RSAKey.VerifyData([System.Text.Encoding]::UTF8.GetBytes($JwsData),$Jws.Signature,$HashAlgorithm,[Security.Cryptography.RSASignaturePadding]::Pkcs1) } 'PS' { $RSAKey = [System.Security.Cryptography.X509Certificates.RSACertificateExtensions]::GetRSAPublicKey($SigningCertificate) [bool] $Result = $RSAKey.VerifyData([System.Text.Encoding]::UTF8.GetBytes($JwsData),$Jws.Signature,$HashAlgorithm,[Security.Cryptography.RSASignaturePadding]::Pss) } 'ES' { $ECDsaKey = [System.Security.Cryptography.X509Certificates.ECDsaCertificateExtensions]::GetECDsaPublicKey($SigningCertificate) [bool] $Result = $ECDsaKey.VerifyData([System.Text.Encoding]::UTF8.GetBytes($JwsData),$Jws.Signature,$HashAlgorithm) } } Write-Output $Result } } } |