When asked how much the agency spent on gaining access to the device, Comey, who was speaking at the Aspen Security Forum in London, said, "A lot. Let's see, more than I will make in the remainder of this job, which is seven years and four months, for sure."

The FBI director's annual salary is $181,500, so that's roughly $1,331,000.

With all the attention the FBI's litigation of Apple garnered, Comey remarked that the court case "stimulated a bit of a marketplace around the world which didn't exist before then."

Earlier this month, Comey revealed that the FBI had purchased "a tool" from a private company but would not elaborate on the company or the services provided.

Comey also said the FBI had no intentions off crowdsourcing more tools for various versions of the iPhone, saying the method would not be scalable due to the costs.

Recognizing that the FBI may need more help in the future cracking various encryption techniques on cell phones, Comey said it will be "a feature of our work" over the "months and years to come."

Instead, Comey said he hopes the FBI can find a sensible solution that does not involve hacking or doling out large amounts of money each time they encounter a new encryption challenge.

Farook and his wife, Tashfeen Malik, killed 14 people in December. The couple, radical Islamists who supported ISIS, later died in a shootout with police.

(CNN)