romcrash.ru

Posted: **01 Apr 2025 02:27**

Basic understanding on how to use computer required.

`text` means quoting technical stuff that is sensitive to case and typos.

# Installation

For Windows I recommend installing git bash, as it comes with gpg and a bunch of other useful unix tools.
https://git-scm.com/downloads

# Usage
Open git bash. Follow further instructions.

Perform `gpg --full-generate-key` command. Choose following options:
```
ECC (sign and encrypt)
NIST P-384
0 (never expire)
```
DO NOT USE REAL NAME IN Real Name FIELD
You can leave most of the fields completely empty.
name it.

Use
`gpg --export --armor key_name`, replacing `key_name` with the key's name. This will export public key that you can send to receiver through insecure channel.
Public keys begin with `-----BEGIN PGP PUBLIC KEY BLOCK-----`.

NEVER SHARE PRIVATE KEYS.

Receive public key from your comrade from which you want to receive messages. Import this key using
`gpg --import file.pgp` or `echo "KEY" | gpg --import`, replacing `file.pgp` with a filepath or `KEY` with the key.

`gpg --edit-key keyname` with key name in place of `keyname` to edit they key.
`sign` to sign the key
`trust` to change trust level
`5` for ultimate trust
`y` confirm
`save` save
- This will get rid of key ownership confirmation upon encryption

Basic way of using gpg is to use `echo "message to encrypt" | gpg --encrypt --armor --recipient key_name` with recipient's key name in the place of key_name. Decryption is `echo "encrypted message" | gpg --decrypt`.

But that's a bit inconvenient, is it?

You may want to use following bash script instead:

Code: Select all

#!/bin/bash

input="$1"

if [[ "$input" == *"-----BEGIN PGP MESSAGE-----"* ]]; then
decrypted=$( echo "$input" | gpg --decrypt )
echo "$decrypted"

else
encrypted=$( echo -e "$input" | gpg --encrypt --armor --recipient key_name | sed -z "s/\n\n/\n/" )

echo "$encrypted"

fi

with `key_name` replaced with recipient's key name.
To use this bash script, simple perform `path_to_script.sh "encrypted/decrypted message"`. It will automatically determine whether you intended to decrypt or encrypt.

File encryption is basically the same. `cat path_to_file.any_format | gpg --encrypt --recipient key_name > path_to_file.format.pgp`. File decryption is accordingly `cat path_to_file.pgp | gpg --decrypt > path_to_file.format`
You can also use this bash script for files:

Code: Select all

#!/bin/bash

file="$1"

if [[ "$file" == *".gpg" || "$file" == *".pgp" ]]; then
        decrypted="$file"
        decrypted="${decrypted%.gpg}"
        decrypted="${decrypted%.pgp}"
        cat "$file" | gpg --decrypt > "$decrypted"
else
        cat "$file" | gpg --encrypt --recipient key_name > "$file".gpg
fi

with `key_name` replaced with recipient's key name.

romcrash.ru

GPG Basic usage tutorial

GPG Basic usage tutorial