Tools to Encrypt/Decrypt and Password Protect Files
Encryption is the process of encoding files in such a way that only those who are authorized can access it. Encryption does not of itself prevent interception, but denies the file content to the interceptor. In an encryption scheme, the intended files, referred to as plaintext, is encrypted using an encryption algorithm, generating ciphertext that can only be read if decrypted.
Linux distribution provides a few standard encryption/decryption tools that can prove to be handy at times. Here in this article we have covered 3 such tools with proper standard examples, which will help you to encrypt, decrypt and password protect your files.
GnuPG (GNU Privacy Guard, often called as GPG) package in most of the today’s Linux distributions comes by default, if in-case it’s not installed you may apt or yum it from repository.
sudo apt-get install gnupg
yum install gnupg
Now you can encrypt file using GPG. As soon as you run the gpg command with option -c (encryption only with symmetric cipher) it will create a file testfile.txt.gpg.
gpg -c /path_to_the_file/testfile.txt
Note: Enter Paraphrase twice to encrypt the given file. The above encryption was done with CAST5 encryption algorithm automatically. You may specify a different algorithm optionally. To see all the encryption algorithm present you may execute:
Now, if you want to decrypt the above encrypted file, you may use the following command:
Note: You need to provide the same password you gave at encryption to decrypt when prompted.
More information about GNU Privacy Guard on official site:
It is one of the most famous archive format and it is so much famous that we generally call archive files as zip files in day-to-day communication. It uses pkzip stream cipher algorithm.
If you have not installed zip you can do it with apt or yum.
sudo apt-get install zip
yum install zip
Create a encrypted zip file using zip:
zip --password mypassword testarchive.zip testfile.txt
Or if you want to add more files into zip archive:
zip --password mypassword testarchive.zip testfile.txt testfile1.txt testfile2.txt
Note: Here mypassword is the password used to encrypt it.
Decrypt the password protected zipped file using unzip:
You need to provide the same password you provided at encryption.
By default OpenSSL is installed in all out templates, however if you have removed it you can install it with apt-get or yum.
sudo apt-get install openssl
yum install openssl
openssl enc -aes-256-cbc -in /path_to_the_file/testfile.txt -out /path_to_the_file/testfile.dat
Explanation of each option used in the above command.
-aes-256-cbc the algorithm to be used.
-in full path of file to be encrypted.
-out full path where it will be decrypted.
Decrypt a file using openssl:
openssl enc -aes-256-cbc -d -in /path_to_the_file/testfile.dat > /path_to_the_file/testfile2.txt