Musetta Saville, who lives in Billingshurst, received a commemorative badge and certificate signed by the Prime Minister David Cameron, as well as personal notes from Horsham MP Francis Maude and Dame Vera Lynn.
Musetta was recruited to the Women’s Royal Naval Service, often referred to as the ‘Wrens’, aged just 17.
Due to the secretive nature of the role, her brother John only found out about her secret life as a coder in recent weeks.
Musetta said: “When I used to go home on leave, my mother used to say ‘run along to bed, dear’, and I used to think to myself that she has no idea what I am doing and the huge responsibility I felt I had.
“My time in the Wrens was not a happy time. I was very young and it was frightening and overwhelming but I am proud that I did my part, even if I couldn’t tell anyone!”
Mr Maude’s letter read: “I understand that you worked as a coder at various Bletchley Park outstations during the Second World War.
“I am very impressed at you having been recruited at such a young age to do this important work.”