How do I convert a .pem file into a .ppk, and vice versa, on Windows and Linux?

Last updated: 2019-10-28

How do I convert my Amazon Elastic Compute Cloud (Amazon EC2) Privacy Enhanced Mail (.pem) file to a PuTTY Private Key (.ppk) file? Or, convert a .ppk file to a .pem file?

Short Description

PuTTY doesn't natively support the private key format (.pem) generated by Amazon EC2. You must convert your private key into a .ppk file before you can connect to your instance using PuTTY. You can use the PuTTYgen tool for this conversion. This tool, available for both Windows and Unix operating system, can convert keys.

Resolution

Windows - install PuTTYgen

Most Windows operating systems have PuTTY installed. If your system doesn't, download and install PuTTYgen.

Windows - convert a .pem file to a .ppk file

Start PuTTYgen, and then convert the .pem file to a .ppk file. For detailed steps, see Convert Your Private Key Using PuTTYgen.

Windows - convert a .ppk file to a .pem file

  1. Start PuTTYgen. For Actions, choose Load, and then navigate to your .ppk file.
  2. Choose the .ppk file, and then choose Open.
  3. (Optional) For Key passphrase, enter a passphrase. For Confirm passphrase, re-enter your passphrase.
    Note: Although a passphrase isn't required, you should specify one as a security measure to protect the private key from unauthorized use. Using a passphrase makes automation difficult, because human intervention is needed to log in to an instance or to copy files to an instance.
  4. From the menu at the top of the PuTTY Key Generator, choose Conversions, Export OpenSSH Key.
    Note: If you didn't enter a passphrase, you receive a PuTTYgen warning. Choose Yes.
  5. Name the file and add the .pem extension.
  6. Choose Save.

Unix or Linux - install PuTTY

Install PuTTY, if it's not already on your system.

Important: A PuTTY package is provided by the Extra Packages for Enterprise Linux (EPEL) repository. You must enable the EPEL repository before you install PuTTY.

To install PuTTY, run one of the following commands:

RPM-based

$ sudo yum install putty

Dpkg-based

$sudo apt-get install putty-tools

Unix or Linux - convert a .pem file to a .ppk file

On the instance shell, run the puttygen command to convert your .pem file to a .ppk file:

$ sudo puttygen pemKey.pem -o ppkKey.ppk -O private

Unix or Linux - convert a .ppk file to a .pem file

Run the puttygen command to convert a .ppk file into a .pem file:

$ sudo puttygen ppkkey.ppk -O private-openssh -o pemkey.pem

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