文字列のハッシュ値を求める関数 (md5sum, sha1sum, sha256sum, sha384sum, sha512sumコマンドと同等の値を返す)

Get-StringHash.ps1

function Get-StringHash {
    [CmdletBinding()]
    param (
        [Parameter(ValueFromPipeline=$true)]
        [string]$InputValue,
        [ValidateSet('MD5', 'SHA1', 'SHA256', 'SHA384', 'SHA512')]
        [string]$Algorithm = 'SHA256',
        [switch]$ToUpperCase
    )
    begin {
        if ([string]::IsNullOrEmpty($InputValue)) {
            $InputValue = ''
        }
        if ([string]::IsNullOrEmpty($Algorithm)) {
            $Algorithm = 'SHA256'
        }
        $hashAlgorithm = [Security.Cryptography.HashAlgorithm]::Create($Algorithm)
    }
    process {
        $hashBytes = $hashAlgorithm.ComputeHash([Text.Encoding]::UTF8.GetBytes($InputValue))
        if ($ToUpperCase) {
            return [BitConverter]::ToString($hashBytes).Replace('-','')
        }
        return [BitConverter]::ToString($hashBytes).Replace('-','').ToLower()
    }
    end {
        $hashAlgorithm.Dispose()
    }
}