Michael Hayden, former director of both the CIA and NSA, says that while he sides more with the FBI in its current case against Apple over the unlocking of the San Bernardino shooter's phone, he tends to agree with Apple on the matter of software back doors in the long run. While backdoors may make the job of law enforcement easier, Hayden feels that such measures would ultimately endanger more Americans.
From USA Today:
"In this specific case, I'm trending toward the government, but I've got to tell you in general I oppose the government's effort, personified by FBI Director Jim Comey," Hayden told Capital Download in an interview about his memoir, Playing to the Edge: American Intelligence in the Age of Terror. "Jim would like a back door available to American law enforcement in all devices globally. And, frankly, I think on balance that actually harms American safety and security, even though it might make Jim's job a bit easier in some specific circumstances."
The concern for Hayden seems to be, primarily, that software backdoors could be used by other entities, such as hackers and foreign governments to spy American citizens. Indeed, this has been one of the concerns raised about the FBI's efforts to have Apple help open the San Bernardino shooter's phone.
Now retired, Hayden served as the Director of the National Security Agency from 1999 to 2005, and the Director of the Central Intelligence Agency from 2005 to 2009.