Understanding mbedtls pem cert convert

When it comes to SSL certificate file formats, there are various types, including .pem, .cer, .jks, .pfx, .der, .p12, .crt, and .p7b files. To navigate the intricate world of certificate conversion, OpenSSL commands come in handy. One of the most important conversions in this realm is the mbedtls pem cert convert. This conversion is crucial for web developers who need to convert their SSL certificates from one format to another to ensure compatibility with different web servers.

What is mbedtls?

Before diving into the specifics of mbedtls pem cert convert, it’s essential to understand what mbedtls is. Mbedtls is a lightweight SSL/TLS library written in C. It’s designed to offer a secure, reliable, and efficient SSL/TLS implementation for embedded systems and IoT devices. Mbedtls provides various cryptographic functions, including symmetric and asymmetric encryption, hashing, and digital signatures. Its small size and low memory footprint make it ideal for resource-constrained environments.

What is a pem certificate?

A PEM certificate is a base64-encoded X.509 certificate that contains the public key of a website. PEM certificates are commonly used for SSL/TLS encryption, and most web servers support them. PEM certificates are stored in a text file and have a .pem extension. They are easy to read and edit, making them a popular choice among web developers.

Why convert pem certificates?

While pem certificates are widely supported, some web servers require different certificate formats. For example, Apache web server uses .crt and .key files, while Nginx uses .pem and .key files. Converting pem certificates to these formats is necessary for web developers to ensure compatibility with different web servers.

How to perform mbedtls pem cert convert

Converting pem certificates to other formats is easy and straightforward using OpenSSL commands. The following are the steps to perform mbedtls pem cert convert:

  1. Open a terminal window and navigate to the directory where the pem certificate is stored.

  2. Run the following command to convert the pem certificate to the desired format:


In this example, we are converting a pem certificate to a DER format. Replace cert.pem with the name of your pem certificate and cert.der with the desired output format.

  1. Verify that the conversion was successful by opening the converted certificate file using a text editor or running the following command:

This command will display the certificate information in human-readable form.

The importance of SSL certificates

SSL certificates are crucial for securing website traffic and protecting sensitive information such as passwords, credit card numbers, and personal information. SSL certificates encrypt the data transmitted between the website and the user’s browser, ensuring that no third party can intercept or read the data. Without SSL certificates, websites are vulnerable to attacks such as man-in-the-middle attacks, where an attacker intercepts the data transmitted between the website and the user’s browser and reads or modifies it.

Other useful OpenSSL commands

In addition to mbedtls pem cert convert, OpenSSL provides various other useful commands for managing SSL certificates. Some of these commands include:

  • openssl req: This command is used to generate a new SSL certificate signing request (CSR) and private key.
  • openssl genrsa: This command is used to generate a new RSA private key.
  • openssl pkcs12: This command is used to convert a PEM certificate and private key to PKCS12 format, which is commonly used for importing SSL certificates into web browsers.

FAQs for mbedtls pem cert convert

mbedtls, formerly known as PolarSSL, is a lightweight cryptographic and SSL/TLS library written in C. It supports a wide range of cryptographic algorithms such as RSA, AES, SHA, etc. and provides functions for SSL and TLS protocol implementation. It is widely used in embedded systems and IoT devices.

PEM stands for Privacy Enhanced Mail and is a file format used to store digital certificates, public and private keys. PEM certificates are Base64-encoded and have a header and footer indicating the certificate type, such as “—–BEGIN CERTIFICATE—–” for X.509 certificates.

How to convert a PEM certificate to DER format using mbedtls?

Mbedtls provides a function mbedtls_pem_read_buffer() to read a PEM certificate from a buffer. To convert it to DER format, we can use the function mbedtls_pem_write_buffer() and extract the DER buffer using mbedtls_pem_write_buffer() parameters. We can then write the DER buffer to a file or use it for other purposes.

How to convert a DER certificate to PEM format using mbedtls?

Similarly, mbedtls provides two functions, mbedtls_pem_write_buffer() and mbedtls_pem_free(), to convert a DER certificate to a PEM format. First, we need to read the DER file using standard file I/O functions and extract it into a buffer. Then, create a mbedtls_x509_crt structure and load the buffer using mbedtls_x509_crt_parse_der(). Finally, we can write the certificate to a PEM file using mbedtls_pem_write_buffer() and free the structure using mbedtls_pem_free().

What are the advantages of using mbedtls for certificate conversion?

Mbedtls is a highly efficient and lightweight library that provides a simple and easy-to-use API for certificate conversion. It supports a wide range of cryptographic primitives and is specifically designed for embedded and IoT devices. It is also open-source and has a large community of users and contributors, ensuring that any security vulnerabilities are quickly identified and fixed.