#==Initialization==
-let ALPHABET_SIZE="32" # number of unique chars in bech32 base32 charset, argument fed to `tr -c` in 'Generate passphrase' step)
+let ALPHABET_SIZE="32" # number of unique chars in bech32 base32 charset
LOG_BASE=2 # Set logarithm base to 2
# Define `echoerr` function which outputs text to stderr
echo "$@" 1>&2;
}
-# Define `rpass` function which generates a base32 passphrase of length $1 (ex: `rpass 22` generates a 22-char string)
+# Define `rpass` function which generates a base32 passphrase of length $1 (ex: `rpass 20` generates a 20-char string)
# Note: function adapted from https://www.thegeekstuff.com/2010/04/unix-bash-function-examples/
# Note: base32 charset uses bech32 charset
function rpass {
#==Main Program==
# Define $ENTROPY_BIT_COUNT1 as argument $1 or prompt user if $1 is not defined.
- # note: argument test adapted from https://stackoverflow.com/a/6482403
+# Note: argument test adapted from https://stackoverflow.com/a/6482403
if [ -z "$1" ]
then
echo "Entropy bit count argument (\$1) not supplied."
fi
# Check if $ENTROPY_BIT_COUNT1 is an non-negative integer
- # Note: Regular expression test is adapted from https://stackoverflow.com/a/806923
+# Note: Regular expression test is adapted from https://stackoverflow.com/a/806923
RETEST1='^[0-9]+$'
if ! [[ $ENTROPY_BIT_COUNT1 =~ $RETEST1 ]] ; then
echo "error: Not an integer." >&2; exit 1
fi
# Calculate minimum count of chars needed to encode $ENTROPY_BIT_COUNT1 with alphabet size of $ALPHABET_SIZE as float
- # Solve ln(a^n)/ln(2)=b for n using `bc` where
- # a=$ALPHABET_SIZE
- # n=$CHAR_COUNT1_FLOAT
- # b=$ENTROPY_BIT_COUNT1
- # Note: `bc` logarithm usage adapted from http://phodd.net/gnu-bc/bcfaq.html#bashlog
+# Solve ln(a^n)/ln(2)=b for n using `bc` where
+# a=$ALPHABET_SIZE
+# n=$CHAR_COUNT1_FLOAT
+# b=$ENTROPY_BIT_COUNT1
+# Note: `bc` logarithm usage adapted from http://phodd.net/gnu-bc/bcfaq.html#bashlog
CHAR_COUNT1_FLOAT=$(echo "$ENTROPY_BIT_COUNT1*l($LOG_BASE)/l($ALPHABET_SIZE)" | bc -l)
- # Note: Float will be of form "21.49744370650136860806". This particular float should be rounded to "22" later.
+# Note: Float will be of form "21.49744370650136860806".
+# Note: This particular example float should be rounded to "22" later.
# Round $CHAR_COUNT1_FLOAT1 up to next highest integer for use as argument in later bash functions.
- # Note: awk expression from https://bits.mdminhazulhaque.io/linux/round-number-in-bash-script.html
+# Note: awk expression from https://bits.mdminhazulhaque.io/linux/round-number-in-bash-script.html
CHAR_COUNT1=$(echo "$CHAR_COUNT1_FLOAT" | awk '{print ($0-int($0)>0)?int($0)+1:int($0)}')
# Generate passphrase