Keys can be exported to text files. These files contain human-readable text at the beginning and at the end of a key. This format is called an ASCII-armored key.
To import keys:
Click Applications › Utilities › Passwords and Keys.
Click File › Import.
Select a file containing at least one ASCII-armored public key.
Click Open to import the key.
You can also paste keys inside Passwords and Keys:
Select an ASCII-armored public block of text, then copy it to the clipboard.
Click Applications › Utilities › Passwords and Keys.
Click Edit › Paste