Yes I will certainly not abandon interactive mode. Non-interactive mode will be in addition to interactive mode. In addition to gathering entropy from the user, I like to present the user with many passwords. Then the user can pick one that seems easy to remember or whatever.

And cryptographic strength in a random number generator does not mean that any encryption is happening. Take a look at my primary random number generator:

Code:

#! /usr/bin/ksh


bc |&

typeset -Z16 Smaster_mwcrng
Smaster_mwcrng=0
Cmaster_mwcrng=0
Xmaster_mwcrng=0

function master_mwcrng {
    print -p "999999*$Xmaster_mwcrng+$Cmaster_mwcrng"
        read -p Smaster_mwcrng
    Cmaster_mwcrng=${Smaster_mwcrng%????????}
    Xmaster_mwcrng=${Smaster_mwcrng##????????*(0)}
        [[ -z $Xmaster_mwcrng ]] && Xmaster_mwcrng=0
}

echo S=$Smaster_mwcrng C=$Cmaster_mwcrng X=$Xmaster_mwcrng
print -n "Enter a seed - "
read Xmaster_mwcrng

i=0
while ((i<30)) ; do
        ((i=i+1))
        master_mwcrng
        echo S=$Smaster_mwcrng C=$Cmaster_mwcrng X=$Xmaster_mwcrng
done

exit 0
S=0000000000000000 C=0 X=0
Enter a seed - 27
S=0000000026999973 C=00000000 X=26999973
S=0026999946000027 C=00269999 X=46000027
S=0045999981269972 C=00459999 X=81269972
S=0081269891190027 C=00812698 X=91190027
S=0091189936622671 C=00911899 X=36622671
S=0036622635289228 C=00366226 X=35289228
S=0035289193076998 C=00352891 X=93076998
S=0093076905275893 C=00930769 X=5275893
S=0005275888654876 C=00052758 X=88654876

The X's are random numbers. This generator will pass any random number test you throw at it. But suppose you knew the first three numbers:
26999973
46000027
81269972
You could have a database of the first three numbers for every possible seed. You could look up these three numbers. Now you know that the seed was 27. And so you can predict every other random number that this generator will output. Thus this random number generator is said to be cryptographically weak. A cryptographically strong RNG is unpredictable.

Just for the heck of it, I wanted a cryptographically strong RNG. So what I do is call the main RNG 500 times and load the results into an array. Then when a command is entered, one of 60 auxiliary RNG's is selected based loosely on the SECONDS variable. This RNG generates a number between 0 and 499. That element of the array is returned and the master RNG is called again to replace it. There's a lot more to it...this is the reader's digest version. Suffice it to say that if you give me the first n random numbers that it outputs, I cannot predict n+1. And it's not just that I don't have enough computers. Infinite computing resources still would not do it. I would also need to know what commands you are entering and the value of the system clock each time that you press return. In addition the automatic stuff that happens, there are user commands to restart the RNG's, scramble the arrays, etc.

In a command line driven version, I will have to select one auxiliary RNG and go with that. No it won't be as secure. The output will be just as good. The danger would come from an evil Perderabo on the system while the password generator is running. He *might* be able to to acquire enough information to guess the generated password.