Key Management - Common Tasks

Create your own asymmetric key

sudo apt install gnupg2 # install GnuPG (GPG)
gpg2 --gen-key # create public-private key pair

• What kind of key you want? Choose RSA and RSA (default).
• What keysize you want? Choose 2048. (If you have a need for extreme security, you can choose 4096.)
• For how long should the key be valid? Choose 0 = key does not expire

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Share your public key

# export public key as a file
gpg2 --armor --export sarah@mullvad.net > sarah.asc
cat sarah.asc # check content

◇ If you want someone to reply with an encrypted message, send this file (public key) to contacts

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Import someone else's public key

gpg2 --import john.asc

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View list of keys

gpg2 -k # public keys
gpg2 -K # private keys

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Using public key's fingerprint

gpg2 --fingerprint [names] # list of fingerprints

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Encrypt a file (message)

• Create a text file and save it. Run the following command

gpg2 --armor --encrypt --recipient john@mullvad.net message.txt

• File message.txt now saved in a new file called message.txt.asc, encrypted, and addressed to recipient using his or her public key
• Attach the file to an email addressed to the recipient

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Decrypt a file (message)

gpg2 --decrypt message.txt.asc > message.txt

• You will be prompted to enter the password

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APT-Key Add Public Key

wget https://www.virtualbox.org/download/oracle_vbox_2016.asc
sudo apt-key add oracle_vbox_2016.asc

Index