NCIS: New Orleans, Season 1

Patton:
I cracked the encryption on Drayer's computer. Chalk up another V for double P. Boy, this Drayer was good. This guy designed a cryptographic attack so that the output of the infected cryptosystem could be computationally indistinguishable from the output of the corresponding uninfected cryptosystem, then used an asymmetric encryption to implement a cryptographic back door.

Pride:
What do you mean by that?

Patton:
Which part?

Pride:
All of it.

Sebastian:
The only thing you gotta understand is back door.

Patton:
Which is what I said.

Sebastian:
Yeah, except I'm saying it in English.