Posts Tagged ‘openssl’

Encrypting files with OpenSSL

Friday, January 9th, 2009

The OpenSSL Project is an Open Source implementation of the Secure Sockets Layer and Transport Layer Security protocols as well as a cryptography library. In this tip I will show you how to encrypt an individual file using the openssl tool.

Probably GPG is a better choice for simple file encryption, but in some ocassions (i.e. encrypt without building keys or certificates) OpenSSL could be very useful. It’s very simple:

openssl enc -aes-256-cbc -salt -in SuperSecretFile.txt -out SuperSecretFile.txt.enc

And your are done! Now to decrypt the file:

openssl enc -d -aes-256-cbc -in SuperSecretFile.txt.enc -out SuperSecretFile.txt

A note from the man pages.

use a salt in the key derivation routines. This option should *ALWAYS* be used unless compatibility with previous versions of OpenSSL or SSLeay is required. This option is only present on OpenSSL versions 0.9.5 or above.

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