# Self Signed & Free Certificates ==================================================================================== #### What are self-signed certificates (OpenSSL)? - **Generated using OpenSSL:** You can generate these certificates yourself without any cost. - **Not Trusted by Browsers:** Browsers and operating systems do not recognize self-signed certificates as trusted because they are not signed by a recognized Certificate Authority (CA). This results in security warnings when users visit your site. - **Use Cases:** Self-signed certificates are typically used for internal testing, development environments, or intranets where trust can be manually configured. #### What are Let'sEncrypt Certificates? - **Generated using Let's Encrypt:** Let's Encrypt is a free, automated, and open CA that provides SSL/TLS certificates. - **Trusted by Browsers:** Certificates from Let's Encrypt are recognized and trusted by all major browsers, ensuring that users won't see security warnings when visiting your site. - **Automation:** The process can be automated using tools like Certbot, which handles the issuance and renewal of certificates. - **Free:** These certificates are provided at no cost. ==================================================================================== ### OpenSSL using OpenSSL, you can generate a private key and a CSR to either: 1. **Send to a Certificate Authority (CA)** to obtain a certificate that will be trusted by browsers and other clients. 2. **Generate a self-signed certificate** for your own use, which will not be trusted by browsers by default but can be useful in certain scenarios. /etc/ssl perms for SSL files needs to be 600 \------------------------------------------------------------------------------------------------------------------------------------------------ ##### Generating a private key and CSR Generate a private key: generating a private key is a prerequisite for creating a Certificate Signing Request (CSR). The private key is essential because it is used to sign the CSR and is part of the SSL/TLS certificate generation process. ``` openssl genpkey -algorithm RSA -pkeyopt rsa_keygen_bits:2048 -out keyfilename.key ``` Generate a CSR: A Certificate Signing Request (CSR) is a block of encoded text that is given to a Certificate Authority (CA) when applying for an SSL/TLS certificate. The CSR contains information about the organization and the public key that will be included in the certificate. ``` openssl req -new -key keyfilename.key -out csrfilename.csr ``` \------------------------------------------------------------------------------------------------------------------------------------------------ ##### Generating a certificate Using the steps above, you will generate a private key and CSR file. We can then use these files to generate a self-signed certificate. ``` openssl x509 -req -days 365 -in csrfilename.csr -signkey keyfilename.key -out crtfilename.crt ``` ==================================================================================== ### LetsEncrypt ------------------------------------------------------------------------------------------------------------------------------------------------ #### Apache [https://www.digitalocean.com/community/tutorials/how-to-secure-apache-with-let-s-encrypt-on-centos-7](https://www.digitalocean.com/community/tutorials/how-to-secure-apache-with-let-s-encrypt-on-centos-7) ##### Running certbot for a single domain ``` sudo certbot --apache -d example.com ``` ##### Running certbot for multiple domains (or subdomains) ``` sudo certbot --apache -d example.com -d www.example.com ``` ##### Auto Renewal ------------------------------------------------------------------------------------------------------------------------------------------------ #### Nginx [https://www.digitalocean.com/community/tutorials/how-to-secure-nginx-with-let-s-encrypt-on-ubuntu-20-04](https://www.digitalocean.com/community/tutorials/how-to-secure-nginx-with-let-s-encrypt-on-ubuntu-20-04) ``` sudo apt install certbot python3-certbot-nginx ``` ``` sudo certbot --nginx -d example.com -d www.example.com ``` ##### Generate a certificate to be manually installed ``` certbot certonly -manual -d example.com -d example.com --webroot -w /path/to/doc/root ``` ##### Auto Renewal ``` systemctl status certbot.timer ``` test renewal: ``` certbot renew --dry-run ```