Helen Lucile Nibouar (née Breese; June 6, 1921 – December 28, 2017) was an American cryptographer who was part of the select group who first worked on the SIGABA cipher device during World War II.

[2] Nibouar had not planned to become a cryptographer, but was recruited at the water fountain by a woman who encouraged her to "give cryptography a try.

"[3] Nibouar then trained at Morrison Field, where she met fellow cryptographer Marion Johnson.

[4] The two worked on the SIGABA cipher device, which was used to obscure troop movements and other sensitive material.

She met her husband, Lieutenant Colonel Grover Cleveland Nibouar Junior, in Japan whilst assigned to the staff of General Douglas MacArthur.