Question

I’m trying to do a very simple thing, namely using a 64-bit password and a 64-bit plaintext (both in hex) and encrypt it with simple old DES.

my script looks like this:

plaintext=`echo -n "$2" | sed 's/\(..\)/\\\x\1/g'`
key=$1
printf "$plaintext" | openssl enc -nosalt -e -des -nopad -K "$key" -iv "0000000000000000" | od --format=x1 --width=32 --address-radix=n | sed 's/ //g'

I execute and get the following result:

./des_enc 5B5A57676A56676E 675A69675E5A6B5A
b617e2c84a4fba2149dd7132433031392257b99d9284b1031c351c15825aca52

The problem is there’s too much data coming back from openssl, I expect to only get 64-bits of data instead I get 512. I don’t know how to explicit request a 64-bit version of DES, is it even possible?

Note: The values used above are from “H. Katzan, The Standard Data Encryption Algorithm, pp75-94, Petrocelli Books Inc., New York, 1977” is:

Key:        5B5A57676A56676E
Plaintext:  675A69675E5A6B5A
Ciphertext: 974AFFBF86022D1F

Answer 1

Use -des-ecb. Also, xxd makes this pipeline much cleaner, if you have it handy (it’s part of the vim package):

sh % echo 675A69675E5A6B5A | xxd -r -ps | openssl enc -des-ecb -nopad -K 5B5A57676A56676E | xxd -ps
974affbf86022d1f