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How to generate the private and public keys?

Table of Contents

Introduction​

This guide will help you to easily generate the private and public keys for nodes and accounts.

Private key generation​

To generate the private keys, run:

openssl ecparam -name secp256k1 -genkey -noout -out priv.key

After the key is generated, you will see the following output:

~ cat ./key.priv.pem

ASN1 OID: secp256k1
-----BEGIN EC PARAMETERS-----
BgUrgQQACg==
-----END EC PARAMETERS-----
-----BEGIN EC PRIVATE KEY-----
MHQCAQEEIFi3694ES2t3WIy1CbGeXsdF7jTQJgd+j9VMkWGsuY1roAcGBSuBBAAK
oUQDQgAEO0Z9+pYftutujvJwKuWaM0L5w0jfi/fIKFypak2csE7jSCAjLDY/GV8y
/fmdC4ksHQQ/ToZhuLDx5yKJiXBbIw==
-----END EC PRIVATE KEY-----

Your private key will be stored in a private key file in the directory you've specified in the command. The private key will be used later to sign all transactions you will perform.

Calculation of a public key out of a private key​

To calculate the public key out of the private key file priv.key, run:

openssl ec -in priv.key -pubout -conv_form compressed > pub.key

After the key is calculated, you will see the following output:

-----BEGIN PUBLIC KEY-----
MDYwEAYHKoZIzj0CAQYFK4EEAAoDIgADO0Z9+pYftutujvJwKuWaM0L5w0jfi/fI
KFypak2csE4=
-----END PUBLIC KEY-----

Extraction of the private key (HEX)​

To extract the private key out of the private key file priv.key, run:

openssl asn1parse -in priv.key -inform pem | grep -e "\[HEX DUMP\]" | cut -d ":" -f4

After the key is extracted, you'll see the following output:

58B7EBDE044B6B77588CB509B19E5EC745EE34D026077E8FD54C9161ACB98D6B

Extraction of the public key (HEX)​

To extract the public key out of the private key file priv.key, run:

openssl ec -in priv.key -noout -text -conv_form compressed 2>/dev/null | grep -A 3 '^pub:' | tail -n 3 | tr '\n' ' '| sed 's/[^01-9a-z]//g' | tr ‘[:lower:]’ ‘[:upper:]’

After the key is extracted, you'll see the following output:

033B467DFA961FB6EB6E8EF2702AE59A3342F9C348DF8BF7C8285CA96A4D9CB04E

Extraction of the public key (DEC)​

To extract the public key out of the private key file priv.key, run:

raw=$(openssl ec -in priv.key -noout -text -conv_form compressed 2>/dev/null | grep -A 3 '^pub:' | tail -n 3 | tr '\n' ' ' | tr -d ' ' | tr ':' ' '); b="";for a in $raw; do b="$b$((16#$a)) "; done; echo $b | tr ' ' ','

After the key is extracted, you'll see the following output:

3,59,70,125,250,150,31,182,235,110,142,242,112,42,229,154,51,66,249,195,72,223,139,247,200,40,92,169,106,77,156,176,78

Attention

If you work with zsh (MacOS) this command needs another cycle parameter:

raw=$(openssl ec -in priv.key -noout -text -conv_form compressed 2>/dev/null | grep -A 3 '^pub:' | tail -n 3 | tr '\n' ' ' | tr -d ' ');IFS=":"; b="";for a in ${=raw}; do b="$b$((16#$a)) "; done; echo $b | sed 's/\ $//' | tr ' ' ','

Otherwise, the line will be parsed incorrectly.