C#

try
{
    Process proc = new Process();
    string keyFile = '\"' + this.PublicSslKeyFile + '\"';
    string sigFile = '\"' + tempSigFile, true) + '\"';
    proc.StartInfo.Arguments = string.Format(" dgst -sha1 -verify {0} -signature {1}", 
                                             keyFile, sigFile);
    proc.StartInfo.FileName = @"C:\openssl\bin\openssl.exe";
    proc.StartInfo.UseShellExecute = false;
    proc.StartInfo.RedirectStandardOutput = true;
    proc.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
    proc.Start();
    StreamReader stdOut = proc.StandardOutput;
    // wait ten seconds for the process to end (this might be too long)
    proc.WaitForExit(10000);
    if (proc.HasExited)
    {
        string results = stdOut.ReadToEnd().ToLower();
        success = results.Contains("verify ok");
    }
}
catch (InvalidOperationException e)
{
    DoSomethingWith(e.ToString());
}

$verify = shell_exec("echo -n \"".$data."\"|openssl dgst -sha1 -verify \"".$public_ssl_key."\" -signature \"".$tmp_signature_file."\"");