PuTTYgen private key
File type: Encoded and encrypted file
A pkk file is a private-key file generated or used by PuTTYgen, the key-generation utility included with PuTTY.
It stores a private key used for authentication with SSH connections.
File type category:
Encoded and encrypted file
Date updated: October 7, 2026
The pkk file extension is associated with PuTTYgen, which is part of the PuTTY suite for Microsoft Windows. PuTTYgen generates public and private key pairs for SSH authentication, including RSA and DSA keys.
A pkk file contains the private portion of a key pair. The file may be protected with a passphrase, which PuTTYgen requests before allowing the key to be used or saved.
Open the file in PuTTYgen, which is included with PuTTY for Microsoft Windows. Load an existing private key and choose the pkk file. Enter its passphrase if prompted.
After loading the key, PuTTYgen can display its public-key information or save it for use by PuTTY.
A pkk file is not normally converted like a document. Use PuTTYgen to load the private key and save it in the private-key format required by PuTTY or another SSH client.
Any export option depends on the key type and the destination software supported by the installed version of PuTTYgen. Keep the private key protected when exporting it.
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