Bitcoin Forum

sudo apt install base58
sudo apt install xxd
sudo apt install qrencode

#! /bin/bash

###############################################
################# FUNCTIONS ###################
###############################################

calculate_checksum(){
        prefix=$1
        value=$2
        suffix=$3
        s1=$(echo -n "${prefix}${value}${suffix}" | xxd -r -p | openssl sha256 | awk '{print $2}')
        s2=$(echo -n ${s1} | xxd -r -p | openssl sha256 | awk '{print $2}')
        checksum=$(echo ${s2} | head -c 8)
        echo ${checksum}
}

hash_160(){
        input=$1
        sha=$(echo -n ${input} | xxd -r -p | openssl sha256 | awk '{print $2}')
        echo -n ${sha} | xxd -r -p | openssl ripemd160 | awk '{print $2}'
}

generate_p2pkh(){
        hash160=$1
        checksum=$(calculate_checksum "00" ${hash160} "")
        echo -n "00${hash160}${checksum}" | xxd -r -p | base58
}

generate_p2sh(){
        input=$1
        hash160=$(hash_160 "0014${input}")
        checksum=$(calculate_checksum "05" ${hash160} "")
        echo -n "05${hash160}${checksum}" | xxd -r -p | base58
}

print_keys(){
        echo "Entropy: "$1
        echo "PK: "$2
        echo "WIF: "$3
        echo "Public Key: "$4
        echo "Compressed Public Key: "$5
        echo "HASH160: "$6
        echo "Legacy Address: "$7
        echo "Segwit Address: "$8
}

print_qr_codes(){
        qrencode -s 6 -l M -o legacy_address.png $1
        qrencode -s 6 -l M -o segwit_address.png $2
}

###############################################
################# MAIN ########################
###############################################

# CONVERT ENTROPY TO WIF KEY

entropy=$1

pk=$(echo -n ${entropy} | openssl sha256 | awk '{print $2}')

checksum=$(calculate_checksum "80" ${pk} "01")

wif=$(echo -n "80${pk}01${checksum}" | xxd -r -p | base58)

# CONVERT PRIVATE KEY TO COMPRESSED PUBLIC KEY USING OPENSSL SECP256K1

public_key=$(openssl ec -inform DER -text -noout -in <(cat <(echo -n "302e0201010420") <(echo -n ${pk}) <(echo -n "a00706052b8104000a") | xxd -r -p) 2>/dev/null | tail -6 | head -5 | sed 's/[ :]//g' | tr -d '\n' && echo)

x_coord=$(printf ${public_key} | cut -c -66 | cut -c 3-)
last_byte=$(printf ${public_key} | cut -c 129-)
last_int=$(printf "%d" 0x${last_byte})
is_odd=$(expr ${last_int} % 2)
if [ "$is_odd" == 1 ]; then
    compressed_public_key=03${x_coord}
else
    compressed_public_key=02${x_coord}
fi

# CONVERTING PUBLIC KEY TO COMPRESSED LEGACY ADDRESS

hash160=$(hash_160 ${compressed_public_key})

legacy_address=$(generate_p2pkh ${hash160})

segwit_address=$(generate_p2sh ${hash160})

# PRINT DATA

print_keys "${entropy}" ${pk} ${wif} ${public_key} ${compressed_public_key} ${hash160} ${legacy_address} ${segwit_address} > data.txt

print_qr_codes ${legacy_address} ${segwit_address}

touch brainwallet.sh

nano brainwallet.sh
<paste the code>
Ctrl+o (save)
Ctrl+x (exit)

chmod u+x brainwallet.sh

./brainwallet.sh 'apogio created a brainwallet generator using bash'

Entropy: apogio created a brainwallet generator using bash
PK: 913fc1abf77ae447c662cbd14a0803e519df65f8c40b3bcb20a911f0f31091dc
WIF: L264Cp6WU73fzmQCvJ8Te2EazXTr3A17yAC13NQDQBwQvyUAaiG3
Public Key: 04582ed090da2d4e4fda943923910a0720391a9903fa5259aa9d50cf3710ed40bbc6ce378a86ab86f2b2d6635e8797e9c4fa2021eff4f57942c22395d7ad1afe83
Compressed Public Key: 03582ed090da2d4e4fda943923910a0720391a9903fa5259aa9d50cf3710ed40bb
HASH160: 8ef81d4f19a7f284e68b32dd58931c6817ceb275
Legacy Address: 1E2xBY8kVhGgNZuRK8RwbvimpeW1E6DPat
Segwit Address: 3MpZWJr5ct3Y4zEeSmbA1R17vj2RrRhfNw