Converting from DES passwords to MD5 and MD5 to DES

To change from DES to MD5:

• Make note of any DES user passwords that exist on your system. MD5 cannot read DES passwords, so any DES passwords you have will have to be changed.

  # vi passwd
  

  You should see something similar to:

  root:$1$93CDf$EQWY0qV7WJ1HBwx3OhOwo/:0:0::0:0::/root:/bin/csh paul:$1$hZQd5kJY$dWKdu.A8O9HOr8Qz2.ck21:1000:20::0:0::/home/dan:/usr/local/bin/bash
  

• MD5 passwords start with '$1$', DES passwords do not; MD5 password hashes are also longer.

  Once you make note of any users whose passwords will have to be changed, exit vi.

• Check that your system is indeed using DES:

  # ls -l /usr/lib/libcrypt*
  lrwxr-xr-x 1 root wheel 11 Aug 15 16:48 /usr/lib/libcrypt.a -> libdescrypt.a
  lrwxr-xr-x 1 root wheel 12 Aug 15 16:49 /usr/lib/libcrypt.so -> libdescrypt.so
  lrwxr-xr-x 1 root wheel 14 Aug 15 16:49 /usr/lib/libcrypt.so.2 -> libdescrypt.so.2

  If your system is using DES, the links will point to libdescrypt.* (If not, the links will point to libscrypt.*).

• Change the symbolic links to point to the MD5 libraries:

  # cd /usr/lib
  # ln -s libscrypt.a libcrypt.a
  # ln -s libscrypt.so libcrypt.so
  # ln -s libscrypt.so.2 libcrypt.so.2

• Reboot the system:

  # init 6

• When the system is back up, enter new passwords for the users who had DES passwords

passwd user

Changing from MD5 to DES:

• Check that your system is indeed using MD5:

  # ls -l /usr/lib/libcrypt*
  lrwxr-xr-x 1 root wheel 11 Aug 15 16:48 /usr/lib/libcrypt.a -> libscrypt.a
  lrwxr-xr-x 1 root wheel 12 Aug 15 16:49 /usr/lib/libcrypt.so -> libscrypt.so
  lrwxr-xr-x 1 root wheel 14 Aug 15 16:49 /usr/lib/libcrypt.so.2 -> libscrypt.so.2

  If your system is using MD5, the links will point to libscrypt.* (If you are already using DES, the links will point to libdescrypt.*).

• 
  
• Change the symbolic links to point to the DES libraries:

  # cd /usr/lib
  # ln -s libdescrypt.a libcrypt.a
  # ln -s libdescrypt.so libcrypt.so
  # ln -s libdescrypt.so.2 libcrypt.so.2

  
  
• Reboot the system:

  # init 6

• When the system is back up, enter new passwords for the users who had DES passwords

passwd user