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

Step 3: Submit CSR details

Follow the process and submit all details.

• Common Name: "KEEP EMPTY"
• Organization: None, or any other name;
• Organization Unit (OU): IT, Security or any other;
• City or Locality: Submit your city;
• State or Province: Submit your State, Region, Province;
• Country: ISO-2 country code, like US, LV, RU, CN, make sure it is allowed country;

Note: Do not submit any key phrase, it will prevent the SSL generation process.

Step 4: Locate CSR file

You will be able to find the CSR file in working directory once the software finished the process of generation. An alternative command to list out all CSRs on your system.

ls *.csr
                                

Step 5: Opening CSR in the console (optional)

You can open the generated .csr file in the editor using the command below.

sudo nano new.csr
                                

Example code

You can open the generated .csr file in the editor using the command below.

openssl req -out new.csr -new -newkey rsa:2048 -nodes -keyout new.key
    Generating a 2048 bit RSA private key
    writing new private key to 'new.key'
-----
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
    Country Name (2 letter code) []:LV
    State or Province Name (full name) []:Rigas
    Locality Name (eg, city) []:Rigas
    Organization  (eg, company) []:None
    Organizational Unit Name (eg, section) []:IT
    Common Name (eg, fully qualified host name) []:
    Email Address []:test@test.tld

Please enter the following 'extra' attributes
to be sent with your certificate request
A challenge password []:                             

Conclusion

That steps are mandatory in order to purchase and order Public IP SSL. You can use that manual to generate classical CSR, just submit Common name.