I need help for this function to verify a p7m file . The funcion return always error value ( -1 ) this is the sintax that I use to verify the sign on the file openssl_pkcs7_verify("prova.p7m", PKCS7_BINARY ,"prova.pdf", array("c:\cert.pem") ); I 'm a winXP user and the path of PHP is place in the system path as mentioned in the setup note why it don't work ? where is the problem ? somebody could help me ?