OK well if you encrypt a compressed file, there are bound to be lots more new redundencies created in the encryption process (unless it is something like ROT-13). Why not compress this AGAIN, squeezing more space out o Actually, you've got it backwards. A decent encryption algorithm, including DES, generates something with very little redundancy, and hence which cannot be compress further. $ compress </vmunix >vmunix.Z $ des -e -k foo <vmunix.Z >vmunix.Z.des des: WARNING: using software DES algorithm $ compress <vmunix.Z.des >vmunix.Z.des.Z -rwxr-xr-x 1 root 1875490 Jan 7 16:59 /vmunix $ des -e -k foo </vmunix | compress >vmunix.des.Z des: WARNING: using software DES algorithm $ ls -l /vmunix vmunix* -rwxr-xr-x 1 root 1875490 Jan 7 16:59 /vmunix -rw-rw-r-- 1 smb 794374 May 21 17:17 vmunix.Z -rw-rw-r-- 1 smb 794376 May 21 17:18 vmunix.Z.des -rw-rw-r-- 1 smb 1066555 May 21 17:18 vmunix.Z.des.Z -rw-rw-r-- 1 smb 2538235 May 21 17:21 vmunix.des.Z As you can see, compressing after encrypting *increases* the size of the file.