Charlie explains, at a high level, how prime numbers are used in modern encryption. He mentions that solving the Riemann Hypothesis could help decrypt current present day encryption, unlocking passwords and bank account information.
The team tests the black box and discovers that it can decrypt data from any encrypted governmental system. One of the members of the group explains that encryption is reliant on complex mathematical computations, and the black box can somehow solve them without an encryption key.
Monica gifts Richard with a framed picture of the text message he sent her, but Richard discovers a comma missing in the picture. Richard sent four but Monica only received three. He realizes this means the message being sent is bypassing encryption because their AI broke it.
Patricia, a cryptanalyst, introduces Alan Turing to the Engima machine and explains how it works. Alan is tasked with breaking the Enigma machine so that the Allies could read the intercepted German messages during World War II.