Why does `od` introduce leading zeros?

Using Solaris 10 ipsec the key must be converted in hex format. So I need a command to convert text in hex. This line works fine echo "mypassword" | od -t x1|head -1|tr -d ' ' |tr [a-z] [A-Z] Produce 00000006D7970617373776F72640A Anyway using an online converter it return this 6D7970617373776F72640A As a workaround I use this echo "mypassword" | od -t x1|head -1|tr -d ' ' |cut -c 8-1000|tr [a-z] [A-Z] it return 6D7970617373776F72640A The question is..why od return those 00000000?