awks

Create a sha256 hash (in uppercase) for each line in a file:
awk '{printf "%s - ",$1 }{"echo -n "$1"|sha256sum"|getline d;split(d,a,"-"); print toupper(a[1])}' notes.txt  

For each line in the 'reps.txt' - create a random string of correct length and do a replace.
for i in `cat reps.txt`; do                                                                                                                                                                              [16:28]
x=`cat /dev/urandom | tr -dc 'a-zA-Z' | fold -w ${#i} | head -n 1`; echo $x;
sed -i "s/$i/$x/g" x6 ;
done