Let's Encrypt vs OpenSSL: What are the differences?

Let's Encrypt and OpenSSL are two widely used tools in the field of web security. Let's explore the key differences between them.

1. Certificate Authority vs Library: Let's Encrypt is primarily a certificate authority that provides free SSL/TLS certificates, whereas OpenSSL is a software library that provides cryptographic functions and protocols.

2. Policies and Trust: Let's Encrypt follows a strict set of policies and practices defined by the CA/Browser Forum to ensure the trustworthiness of its certificates. OpenSSL, on the other hand, is a more flexible tool that allows the creation and manipulation of cryptographic keys and certificates without enforcing specific trust policies.

3. Automation and Renewal: Let's Encrypt promotes the automation of certificate issuance and renewal through its ACME protocol, which enables seamless integration with various web servers and operating systems. OpenSSL does not provide built-in automation mechanisms, and the renewal process must be managed manually.

4. Pricing: Let's Encrypt provides its SSL/TLS certificates free of charge, making it an attractive option for organizations with limited budgets. OpenSSL, being a software library, is also free but requires the implementation and management of the necessary infrastructure.

5. Community Support and Development: Let's Encrypt has a large and active community that provides support, updates, and improvements to the service. OpenSSL also has a dedicated community but is primarily maintained by the OpenSSL Software Foundation, which consists of a smaller group of developers.

6. Validation Types: Let's Encrypt supports domain validation, which verifies control over the domain by checking DNS records or through HTTP-based challenges. OpenSSL can generate certificates with various validation types, including domain, organization, and extended validation, providing more customization options.

In summary, Let's Encrypt is a certificate authority focused on providing free SSL/TLS certificates with automated issuance and renewal, while OpenSSL is a versatile software library for cryptographic functions with broader flexibility but requires manual management and does not offer certificate authority services.