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Generating OpenSSH-compatible Keys for Use with PuTTY

To generate a set of RSA keys with PuTTYgen:

1. Start the PuTTYgen utility, by double-clicking on its .exe file;
2. For Type of key to generate, select RSA;
3. In the Number of bits in a generated key field, specify either 2048 or 4096 (increasing the bits makes it harder to crack the key by brute-force methods);
4. Click the Generate button;
5. Move your mouse pointer around in the blank area of the Key section, below the progress bar (to generate some randomness) until the progress bar is full;
6. A private/ public key pair has now been generated;
7. In the Key comment field, enter any comment you’d like, to help you identify this key pair, later (e.g. your e-mail address; home; office; etc.) — the key comment is particularly useful in the event you end up creating more than one key pair;
8. Optional: Type a passphrase in the Key passphrase field & re-type the same passphrase in the Confirm passphrase field (if you would like to use your keys for automated processes, however, you should not create a passphrase);
9. Click the Save public key button & choose whatever filename you’d like (some users create a folder in their computer named my_keys);
10. Click the Save private key button & choose whatever filename you’d like (you can save it in the same location as the public key, but it should be a location that only you can access and that you will NOT lose! If you lose your keys and have disabled username/password logins, you will no longer be able log in!);
11. Right-click in the text field labeled Public key for pasting into OpenSSH authorized_keys file and choose Select All;
    Right-click again in the same text field and choose Copy.
12. NOTE: PuTTY and OpenSSH use different formats for public SSH keys. If the SSH Key you copied starts with “—- BEGIN SSH2 PUBLIC KEY …”, it is in the wrong format. Be sure to follow the instructions carefully. Your key should start with “ssh-rsa AAAA ….”
13. Save The Public Key On The Server

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