If you’re working with SSL certificates, you may have come across the need to convert PEM files to SSH-RSA format. This can be a daunting task if you’re not familiar with the process, but fear not! In this article, we’ll walk you through the steps of converting PEM to SSH-RSA format.
What is PEM Format?
Before we dive into the conversion process, let’s briefly discuss what PEM format is. PEM stands for Privacy Enhanced Mail, and it is a base64 encoded format used for encoding SSL certificates, keys, and other sensitive information. PEM files are usually identified by the file extension .pem, .crt, or .key.
What is SSH-RSA Format?
SSH-RSA format is a way of encoding SSH keys used for SSH logins. It is based on the RSA algorithm and is widely used for secure communications over the internet. SSH-RSA keys are usually identified by the file extension .pub.
Step 1: Convert PEM to DER Format
To convert PEM to SSH-RSA format, we first need to convert the PEM file to DER format. DER stands for Distinguished Encoding Rules and is a binary format used for encoding SSL certificates and keys. To convert PEM to DER, we’ll use the OpenSSL command-line tool.
Open a terminal window and enter the following command:
openssl x509 -outform der -in certificate.pem -out certificate.der
This command will convert the PEM file named certificate.pem to DER format and save it as certificate.der.
Step 2: Convert DER to SSH-RSA Format
Now that we have the certificate in DER format, we can convert it to SSH-RSA format using the following command:
ssh-keygen -i -f certificate.der > certificate.pub
This command will take the DER-encoded certificate file named certificate.der and convert it to SSH-RSA format, saving the result in a file named certificate.pub.
FAQs for Convert PEM to SSH-RSA
What is PEM and SSH-RSA?
PEM (Privacy Enhanced Mail) is a base64-encoded encrypted format used to store and manage certificates and private keys. While SSH-RSA (Secure Shell – Rivest, Shamir, Adleman) is a public-key cryptography system widely used for secure remote login from one computer to another.
Why do I need to convert PEM to SSH-RSA?
You may need to convert PEM to SSH-RSA format when you want to use an SSH key to authenticate a remote service or SSH server.
How can I convert PEM to SSH-RSA?
To convert PEM to SSH-RSA, you should use the command-line tool OpenSSL. First, ensure that you have a PEM-formatted private key. Next, run the following command – openssl rsa -in privkey.pem -outform pem > ssh_key.rsa – and replace privkey.pem with the name of your PEM key file. This command will convert the PEM key to SSH-RSA format and save it as an RSA key file.
Is it possible to convert SSH-RSA to PEM?
Yes, it is possible to convert SSH-RSA to PEM. Again, you can use OpenSSL to convert SSH-RSA to PEM format. The command for this is openssl rsa -in ssh_key.rsa -outform PEM -out privkey.pem where ssh_key.rsa is the name of your SSH-RSA key file. This command will save your SSH-RSA key in PEM format as privkey.pem.
Are there any tools or websites to convert PEM to SSH-RSA?
Yes, there are several online tools and websites that can also convert PEM to SSH-RSA. Users can use Puttygen, an open-source tool available for Windows and Unix-like systems. You need to load the PEM file into Puttygen, enter a passphrase if needed, and click on the “Convert” button. The tool will generate a new key in either the SSH-1 or SSH-2 format, depending on your chosen options.
In summary
PEM and SSH-RSA are two different formats used to store and manage certificates and private keys. To convert PEM to SSH-RSA, you should use OpenSSL; you can also use Puttygen, which can convert PEM files to SSH format and vice versa. Make sure you have a backup of important keys before attempting any conversion.