picoCTF 2025 – Cryptography • Easy
We can observe that the message has a curly braces at 8th and at the last place.
16 9 3 15 3 20 6 { 20 8 5 14 21 13 2 5 18 19 13 1 19 15 14 }This looks like the pattern of a flag but with the letters substitued with numbers. It is in fact a substitution cipher.
We observe that if we substitute each number with the letter which position in the alphabet is given by the numnber, we obtain a string that start with 'picoCTF'. This is our flag.