rename and simplify section about the major system.

Author: Lucien Grondin

README.md

@@ -36,7 +36,7 @@ $ mnemonic=($(create-mnemonic 128))
 $ echo "${mnemonic[@]}"
 
 $ mnemonic-to-seed "${mnemonic[@]}" > seed
-$ pegged-entropy {1..38} > seed
+$ dc -e "$((RANDOM))P" > seed
 
 $ xkey -s /N < seed
 $ ykey -s /N < seed
@@ -301,34 +301,15 @@ The passphrase can also be given with the `BIP39_PASSPHRASE` environment variabl
 
 <a name=major />
 
-#### Major system
+#### Memory Techniques
 
-As an alternative to bip-39, bitcoin-bash-tools includes a function
-called `pegged-entropy` wich prompts decimal numbers from 0 to 99
-and uses them to generate a byte stream that can then be used as input
-for `bip32`. The generated extended key can then be used by `bip85`
-to produce all sorts of entropy for various applications.
+An alternative to bip-39 is to use [memory techniques](https://artofmemory.com/).
 
-The numbers are between 0 to 99 to facilitate the use of the so-called
-[major system](https://en.wikipedia.org/wiki/Mnemonic_major_system).
-
-To memorize the sequential order of the numbers, either the
-[method of loci](https://en.wikipedia.org/wiki/Method_of_loci) or the
-[peg system](https://en.wikipedia.org/wiki/Method_of_loci) can be used.
-
-The function takes as argument the pegs to use. For the method of loci,
-a sequence of integers can be used.
-
- $ pegged-entropy {1..10}
-
-Pegs do not have to be secret, so they can be saved in a file or in
-a variable in plain text.
-Here is an exemple from http://thememoryinstitute.com/the-peg-system.html :
-
- $ pegs=(Bun Shoe Tree Door Hive Sticks Heaven Gate Vine Hen)
- $ pegged-entropy "${pegs[@]}"
-
-This function will escape non-printable characters when writing to a terminal.
+Once you've become familiar with these techniques, you can generate a seed in
+several ways, you just have to make sure you remember your choice of encoding.
+For instance, if you've memorized a long number in decimal, you could either
+use its representation in ASCII or a byte stream generated from it with dc's
+`P` command.
 
 <a name=addresses />
 

bitcoin.sh

@@ -623,39 +623,6 @@ isPublic() ((
  $1 == BIP32_MAINNET_PUBLIC_VERSION_CODE
 ))
 
-pegged-entropy()
- if (( ${#@} == 0 ))
- then
- echo "no peg was provided" >&2
- return 1
- elif test ! -t 0
- then
- echo "$FUNCNAME will only read input from a terminal" >&2
- return 2
- else
- local peg
- local -i i c
- {
- for peg in "$@"
- do
- read -p "$peg $((++i))/${#@}: "
- if ((REPLY > 99 || REPLY < 0))
- then
- echo "input out of range" >&2
- return 2
- fi
- # https://stackoverflow.com/questions/9134638/using-read-without-triggering-a-newline-action-on-terminal
- echo -en "\033[1A\033[2K" >&2
- ((c += REPLY))
- printf "%02d" "$REPLY"
- done
- echo " P"
- echo "checksum is $((c % 100))" >&2
- } |
- dc |
- escape-output-if-needed
- fi
-
 bip32()
  if
  local header_format='%08X%02X%08X%08X'