Yes, you need a certificate. This is explained in Apple docs. One catch, you probably need to convert the certificate to .pem format. The .pem certificate must include both the certificate and the RSA private key.
Here is a good site to read: http://www.macoscoders.com/2009/05/17/iphone-apple-push-notification-service-apns/
My pem looks like this:
Bag Attributes friendlyName: Apple Development Push Services: <my data> localKeyID: <my local key in hexascii> subject=/UID=com.my.push.sandbox1/CN=Apple Development Push Services: <my data>/C=US issuer=/C=US/O=Apple Inc./OU=Apple Worldwide Developer Relations/CN=Apple Worldwide Developer Relations Certification Authority -----BEGIN CERTIFICATE----- <my certificate data omitted> -----END CERTIFICATE----- -----BEGIN RSA PRIVATE KEY----- <my key data omitted> -----END RSA PRIVATE KEY-----
zaph source share