Her research has applied mathematical logic in the formal verification of cryptographic protocols, and has included the development of secure electronic voting systems.
She has also contributed to the public dissemination of knowledge about cryptography through a sequence of posts on the binaire blog of Le Monde.
Cortier studied mathematics and computer science at the École normale supérieure de Cachan from 1997 until 2001, earning a master's degree and completing her agrégation.
She remained at Cachan for her doctoral studies, completing a Ph.D. in 2003 with the dissertation Automatic Verification of Cryptographic Protocols supervised by Hubert Comon.
[3][4] In 2015 she became the second woman to win the INRIA and French Academy of Sciences Young Researcher Award for her work on Belenios, a secure electronic voting system.