You are missing the loop. After adding that and usual straightforward golf tricks, plus an examination of their data set, you get down to: 
perl -pe's~(\d)(.)(.)/~chr$1*16+$2*4+$3+64~ge' DATA_FILE

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In reply to Re (tilly) 1: Canadian Cryptography Contest by tilly
in thread Canadian Cryptography Contest by jryan

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