Bitcoin Forum

#!/bin/bash
#bitpoa: Bitcoin blockchain based proof of authenticity
#Author: Wolciph
#Public domain, use at your own risk
set -e

#config:
interactive=1
hashAlgo=sha256
amount=0.00000001
fee=0.0001
keyType=pk
infoFile='info.poa'

bitcoind=~/bitcoind
bitcoinDir=~/.bitcoin/
dbdump=~/bitcointools/dbdump.py

cd "$(dirname "$0")"
. addrgen.so.bash
#. bitpoa.conf
cd - >/dev/null

_tries=5
get_transaction_block() #(txid)
{
	#workaround to access block of transaction:
	local c=$($bitcoind getblockcount)
	local b=$($bitcoind gettransaction $1 |
		grep -m1 '"confirmations" :' |
		sed -r 's/^.*"confirmations" : ([0-9]*).*$/\1/g';
		[[ ${PIPESTATUS[@]} = '0 0 0' ]])
	local c2=$($bitcoind getblockcount)
	if (( $c2 == $c )); then echo $((c - b + 1))
	elif (( _tries > 0 )); then ((_tries--)); get_transaction_block
	else 
		echo "Cannot get stable blockcount. Wait until your blockchain is up\
		to date and try again." >&2
		return 2
	fi
}
get_field() #(field)
{
	grep -m1 "^$1:" | sed -r "s/^$1:(.*)$/\1/g"
	[[ ${PIPESTATUS[@]} = '0 0' ]]
}

check_pipes() { [[ "${PIPESTATUS[@]}" =~ ^0(\ 0)*$ ]]; }

help="bitpoa Bitcoin blockchain proof of authenticity tool:
Examples:
  These tasks require the bitcoin server to be active:
    Creation: $0 -cf document.txt -i info.poa -a sha256 -A 0.00000001
    Finding the block: $0 -b -i info.poa
  This task requires the bitcoin server to be stopped:
    Verifying: $0 -vf document.txt -i info.poa
Commands:
	-c, --create : create and send _amount_ coins to a new address
	-b, --find-block : find the block in which the new transaction is to
		complete the info file
	-v, --verify : verify a POA
	-f, --file= : file from which to create a hash
	-i, --info-file= : info file to read or write info for checking the POA
	-h, --hash : do not hash the file (to use if it already is a hash)
	-a, --algo= : the hashing algorithm; uses openssl
	-y, --assume-yes : do not prompt before critical operations, non-interactive
	-s, --secret-key : use hash in the private key (NOT IMPLEMENTED)
	-A, --amount= : amount of bitcoins to send (WILL BE LOST FOREVER!!!)
	-F, --fee= : transaction fee
"
#------------------

OPTS=$(getopt -o cvbf:i:ha:yA:F: \
	--long create,verify,find-block,file:,info-file:,hash,algo:,assume-yes,help,amount,fee\
	-n "$0" -- "$@")
if [ $? != 0 ]; then echo "Terminating. Use --help for help." >&2; exit 1; fi
eval set -- "$OPTS"
while true; do
	case "$1" in
		-c|--create) action=create; shift;;
		-v|--verify) action=verify; shift;;
		-b|--find-block) action=findBlock; shift;;
		-f|--file) file="$2"; shift 2;;
		-i|--info-file) infoFile="$2"; shift 2;;
		-h|--hash) hash=1;; #the file cointains the hash
		-a|--algo) hashAlgo="$2"; shift 2;; #first round (followed by ripemd160)
		-y|--assume-yes) interactive=0; shift;;
		-s|--secret-key) keyType=sk; shift;;
		-A|--amount) amount=$2; shift 2;;
		-F|--fee) txfee=$2; shift 2;;
		--help) printf "%s" "$help" >&2; exit 0;;
		--) shift; break;;
		*) echo "Invalid argument: $1. Use --help for help." >&2; exit 1;;
	esac
done
[ -n "$1" ] && { echo "Unknown extra argument: $1" >&2; exit 1; }
[ -z "$action" ] && { echo 'No action specified (-c|-v|-b)' >&2; exit 1; }

if [[ $action = findBlock ]]; then
	txid="$(get_field txid < $infoFile)"
	block=$(get_transaction_block $txid)
	printf "%s\n" "block:$block" >> $infoFile
	exit 0
fi

if [[ "$hash" = '1' ]]; then 
	hash=$(cat "$file")
else
	hash=$(cat "$file" | openssl dgst -$hashAlgo -hex; [[ ${PIPESTATUS[@]} = '0 0' ]];) ||
	{ echo "Error while hashing using $hashAlgo. Exiting." >&2; exit 1; }
fi

if [[ $keyType = pk ]]; then
	h=$(xxd -p -r <<< "$hash" | openssl dgst -rmd160)
	address=$(hash160ToAddress $h)
else
	exit 1
	#use hash as seed for prng?
fi

if [[ $action = 'create' ]]; then
	printf "%s\n%s\n%s\n" "file:$file" "algo:$hashAlgo" "address:$address" > $infoFile
	cmd="$bitcoind -paytxfee=$txfee sendtoaddress $address $amount"
	if [[ $interactive = '1' ]]; then
		echo "Warning: $amount bitcoins will be lost forever." >&2
		printf '%s\n%s\n%s\n' "The following command is about to be sent to the bitcoin daemon:"\
		"$cmd" "Make sure it is running. Proceed? (y/n)" >&2
		read r
		[[ "$r" =~ ^y(es?)?$ ]] || exit 0
	fi
	echo -n 'txid:' >> $infoFile
	eval $cmd >> $infoFile
	if [[ $interactive = '1' ]]; then
		printf "%s%s\n" 'You must now wait for the transaction to be '\
		"integrated into a new block before launching $0 -b [...]" >&2
	fi
elif [[ $action = 'verify' ]]; then
	address2="$(get_field address < $infoFile)"
	if [[ "$address2" != "$address" ]]; then 
		printf "%s\n" "FAILURE: The address is incorrect (should be $address)!" >&2
		exit 5
	fi
	block=$(get_field block < $infoFile)
	blockInfo="$($dbdump --block=$block)"
	if ! (grep -m1 "pubkey: $address" <<< "$blockInfo"); then
		echo "FAILURE: The address is correct but does not appear in the given block!" >&2
		exit 6
	fi
	echo "The address is correct and was published in the blockchain at around:"
	grep -m1 '^Time: ' <<< "$blockInfo" | sed -r 's/Time: (.*) Nonce:.*$/\1/'
fi

  These tasks require the bitcoin server to be active:
    Creation: ./bitpoa.bash -cf document.txt -i info.poa -a sha256 -A 0.00000001
    Finding the block: ./bitpoa.bash -b -i info.poa
      (for creation, a second step must be taken to find the block of the transaction in order to speed up verification)
  This task requires the bitcoin server to be stopped:
    Verifying: ./bitpoa.bash -vf document.txt -i info.poa

file:bitpoa.bash
algo:sha256
address:1Dga4BiLThvbFeA7b2sxzQx2G85uCk67kr
txid:9209f8bfaa967cf2530a6a708ac12b370615ca4e4d5242e8bc28261f12522bce
block:142683

bitpoa -v -f bitpoa.bash -i bitpoa.bash.poa