SSL certificate for Localhost

Solution 1: Self-Signed SSL

Self-signed certificates generated via openssl or others. Here is the easiest way to generate a private key and a self-signed certificate for localhost:

openssl req -x509 -out localhost.crt -keyout localhost.key \
  -newkey rsa:2048 -nodes -sha256 \
  -subj '/CN=localhost' -extensions EXT -config <( \ printf "[dn]\nCN=localhost\n[req]\ndistinguished_name = dn\n[EXT]\nsubjectAltName=DNS:localhost\nkeyUsage=digitalSignature\nextendedKeyUsage=serverAuth")

But such a certificate will cause trust errors in browsers because there is no corresponding certification authority in the trusted store.

Solution 2: mkcert

The trick is to register a new domain like localhost.example.com, which locally resolves to 127.0.0.1 (in / etc / hosts), to get the usual certificate for this domain. But such fraud is questionable from a security point of view - at least for public services such a resolving is highly not recommended because of a possible MiTM attack with a change to a hostile IP address. If we restrict ourselves only to the local machine, then this may be a suitable option, although there are also some doubts. In addition, such certificate may be revoked. In any case, there is a simpler and safer option (see below).

This is mkcert, a simple utility for generating locally trusted certificates with its own certification authority. It works under all OSs and does not require any configuration.

For Linux

First you have to install certutil.

sudo apt install libnss3-tools
-or-
sudo yum install nss-tools
-or-
sudo pacman -S nss

Then do:

brew install mkcert
                                

or compile from source:

go get -u github.com/FiloSottile/mkcert
$(go env GOPATH)/bin/mkcert

For MacOS

Follow the next command:

brew install mkcert
brew install nss # if you use Firefox

For Windows

You can download the collected binaries or use one of the package managers: Chocolatey or Scoop.

choco install mkcert
-or-
scoop install mkcert