# CCS'16 Key Sharing Datasets
# Certificate to Third-Party Hosting Services Mapping
# Frank Cangialosi (frankc@csail.mit.edu)
# November 2016

cert-to-tph.txt lists the hosting services we observed to be serving a given
certificate during any of our scans, which we also deemed to be a third-party.
For more details on this classification please see sections 4.2 and 4.3 of our
paper.

The file contains three space-separated columns:

1. Certificate Hash*
2. Comma-separated list of providers identified by rDNS+
3. Comma-separated list of providers identified by ASN+

* NOTE: This certificate hash is the same as column 1 in the primary
	certificate dataset.

+ NOTE: We only include the AS Organization for a given IP address in column (3)
	if we were not able to first find an rDNS record for that IP. Thus, we do
	not double count providers across columns 2 and 3, and one can get the total
	number of unique third-party hosting providers for a given certificate
	by simply adding up the number of elements in columns 2 and 3.