It's at the bottom of PDF page 3--search for "encryption."

Excerpt:

Unfortunately, changing forms of Internet communication and the use of encryption are posing real challenges to the FBI’s ability to fulfill its public safety and national security missions. This real and growing gap, which the FBI refers to as “Going Dark,” is an area of continuing focus for the FBI; we believe it must be addressed, since the resulting risks are grave both in both traditional criminal matters as well as in national security matters.