Keypair (public and a private key)

About

A keypair is a pair of keys:

a public key: Used for encryption or signature verification;
and a private one: The decryption key which is kept secret decrypt and sign.

They are a component of the public key scheme.

For some software such as portcle, a keypair is:

a private key
and its certificate

Because the public key is generated from the private key

Usage

Note that a public key can be regenerated from the private key. A keypair is mostly generated for public key authentication where you need the 2 at once.

Management

Format

See File format for key

Creation

Different tool create different format.

The keygen tool of OpenSSH has become the default tool as OpenSsh is now supported on Windows and Linux platform.

keygen

How to create a keypair with OpenSSH KeyGen? to create a key pair in the pem format

keytool

With the Java keytool utility, generation of a keypair and creation of a (Java) key store (Jks) with the rsa implementation algorithm.

keytool \
    -genkeypair 
    -alias aliasEntry
    -keyalg RSA 
    -keystore keyStoreName.jks 
    -dname "[email protected], CN=KeyName, OU=Programs Partners, O=Organisation, L=Town, C=NL" 
    -storepass keyStorePassword 
    -keysize 2048 
    -keypass keyPassword

where:

dname is the What is the LDAP Distinguished Name (DN)?

putty

Putty has a tool to create key pair in a ppk format