How to encrypt and decrypt a file using gpg command on linux



There are many choices on hand to secure your data. However, GPG provides the additional benefit to encrypting your data on a priority basis and transfers them securely over the internet. This article explains about – How to Encrypt and Decrypt a file using GPG command on Linux.

To get more information about GPG, use the following command –

$ gpg -h

The sample output should be like this –

gpg (GnuPG) 1.4.20
Copyright (C) 2015 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Home: ~/.gnupg
Supported algorithms:
Pubkey: RSA, RSA-E, RSA-S, ELG-E, DSA
Cipher: IDEA, 3DES, CAST5, BLOWFISH, AES, AES192, AES256, TWOFISH,
   CAMELLIA128, CAMELLIA192, CAMELLIA256
Hash: MD5, SHA1, RIPEMD160, SHA256, SHA384, SHA512, SHA224
Compression: Uncompressed, ZIP, ZLIB, BZIP2

Syntax: gpg [options] [files]
Sign, check, encrypt or decrypt
Default operation depends on the input data

Commands:

-s,       --sign [file]        make a signature
          --clearsign [file]   make a clear text signature
-b,       --detach-sign        make a detached signature
-e,       --encrypt            encrypt data
-c,       --symmetric          encryption only with symmetric cipher
-d,       --decrypt            decrypt data (default)
          --verify             verify a signature
          --list-keys          list keys
          --list-sigs          list keys and signatures
          --check-sigs         list and check key signatures
          --fingerprint        list keys and fingerprints
-K,       --list-secret-keys   list secret keys
          --gen-key            generate a new key pair
          --delete-keys        remove keys from the public keyring
          --delete-secret-keys remove keys from the secret keyring
          --sign-key          sign a key
          --lsign-key         sign a key locally
          --edit-key          sign or edit a key
          --gen-revoke       generate a revocation certificate
          --export           export keys
          --send-keys        export keys to a key server
          --recv-keys        import keys from a key server
          --search-keys      search for keys on a key server
          --refresh-keys     update all keys from a keyserver
        --import import/merge keys
--card-status print the card status
--card-edit change data on a card
--change-pin change a card's PIN
--update-trustdb update the trust database
--print-md algo [files] print message digests
...............................................................................

While encrypting and decrypting a file, it will ask to Enter passphrase(password) and Repeat passphrase to secure a file

Encrypt a File using GPG

To encrypt a file using GPG, please use the command as shown below –

$ gpg -c abc.txt

In the above command, it is encrypting abc.txt file. To verify it, use the following command –

$ ls

The sample output should be like this –

abc.txt               Final_Url_Weight.csv           site_health_depth5.txt
abc.txt.gpg           FINAL_URL_WEIGHT.db            tp_Crawled_few.txt
check_ageof_site.py   final_url_weight.py
extracting_keywors.py final_url_weight_sqlite.py

Decrypt a File using GPG

To decrypt the above file, use the following command –

$ gpg -o abc.txt -d abc.txt.gpg
gpg: AES encrypted data
Enter passphrase:

Above the command de-crypts the file and stores in same directory.

In the above article, we have learnt – Learn how to Encrypt and Decrypt a file using GPG command on Linux. In our next articles, we will come up with more Linux based tricks and tips. Keep reading!

Samual Sam
Samual Sam

Learning faster. Every day.


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