Pupils at Penwortham's Priory Academy proved top code-breakers after coming joint first in a national competition.
Every year, the University of Southampton runs a cipher competition, this year called the Kompromat Files.
More than 100 schools entered the competition and started the challenge in September solving two encrypted texts a week for 10 weeks.
Priory Year 11s Danyal Raza, Jacob Haddon, Christian Rigby, with help from maths Teacher Ciaran Henshaw, scored 10 out of 10 in part A and nine out of 10 in part B to finish joint first.
“The one we couldn’t do was virtually unsolvable,” said Danyal
“We have all enjoyed it, It has challenged us and we have been determined to crack as many as we can. There have been disagreements between us but we are proud to have done as well as we have.”
Mr Henshaw said: “Some of the problems these students were solving were up to degree standard.”
“Students could enter up to 18 so our students were younger entrants and to have done so well is outstanding for Priory.”