Detailed explanation of ubuntu using gpg2

installation##

apt-get install gnupg2

Generate key pair##

gpg2 --full-generate-key
# Then, just fill in as prompted
gpg2 --list-keys
# Output
pub   rsa2048 2020-01-02[SC]
  6 CFAA44AC11E041B0181988352FC3xxxxC39FF406
uid           [absolute] haha <[email protected]>
sub   rsa2048 2020-01-02[E]

Note that this [email protected] is the user ID
6 CFAA44AC11E041B0181988352FC3xxxxC39FF406 is the user ID

Export public key##

gpg2 --armor --output ~/public-key.txt --export [email protected]

Now in the ~ directory, your public key will appear

Export private key##

gpg2 --armor --output ~/private-key.txt --export-secret-keys [email protected] 

Upload the public key to the server##

# 6 CFAA44AC11E041B0181988352FC3xxxxC39FF406 is the user identification, in--list-keys can be viewed
gpg2  --keyserver hkp://keyserver.ubuntu.com --send-keys 6CFAA44AC11E041B0181988352FC3xxxxC39FF406

At this point, you can search for your public key##

gpg2  --keyserver hkp://keyserver.ubuntu.com --search-keys "[email protected]"

Here is a screenshot:

Download public key##

# First search [email protected], figure out the id, then
gpg2 --keyserver keyserver.ubuntu.com --recv 52FC3B13C39Fxxx6

at this time:

gpg2 --list-keys
/root/.gnupg/pubring.kbx
------------------------
pub   rsa2048 2020-01-02[SC]
  6 CFAA44AC11E041B01819883xxxxxxx9FF406
uid           [ unknown] xxxxx <[email protected]>
sub   rsa2048 2020-01-02[E]

The public key can be found.

encryption##

gpg2 --recipient [email protected] --output test2.txt --encrypt test.txt

After importing the public key, you can use the public key to encrypt. test.txt is the source file, test2.txt is the encrypted file

Decryption##

Send the encrypted file to the party who has the private key.

gpg --recipient [email protected] --output testde.txt --decrypt ./test2.txt

At this time, you will be asked to enter the protection password when creating the key pair. After entering the password, the testde.txt file is generated.