There are two parts to security - Authentication of queries and replies and Authorization of routing info. Bad routes get into ASes from border Ases, there can be malicious injection. The IRR can be used for filtering on prefixes. Thus one can announce a subnet of an enemy and black-hole their traffic. A registry is just a clearing house some info is secure, some not.
Response includes query.
The old one can be deleted. Issue of renumbering and grace periods was not resolved. Daniel said that Authentication is currently being tackled by the RIPE Database Security Task Force which includes people from a number of Routing Registries. He also said that there is a relationship between the routing announcements made by an AS and the address assignment data. This relationship should be clearly documented.