Rather, shc can be considered a shell script obfuscater which makes it hard for any non tech-savvy user to peak inside a shell script. You are not supposed to rely on shc to hide any confidential shell script from a determined adversary. So relatively straightforward disassembling steps can reveal the encryption password and restore the original shell script. Besides, the adoption of RC4 in shc is particularly weak due to the fact that an encryption key is carried inside the encrypted script itself. The type of encryption used by shc is a variant of RC4 stream cipher, which is already known to be insecure and prohibited for use in TLS. The generated C code is then compiled by cc compiler into a binary executable. Instead, what shc does is to generate a C code which contains the original shell script in an encrypted form, with added functionality for expiration handling. Unlike actual compilers like gcc, shc does not translate the script's source code into lower-level machine language code. What is shc?īilled as a 'generic script compiler' by its author, shc converts any shell script into a binary executable that behaves exactly like the original script. Before demonstrating actual usage of shc, let me explain how shc works and clarify the role of shc. In this tutorial, I describe how you can encrypt your shell script with an open-source tool called shc. Better yet, you want to set the expiration date on the script, so that the script may not be used beyond the set expiration date. For example, for whatever reason you don't want the shell script to be viewed for inspection and modified for re-distribution by others. Suppose you have written a bash shell script and you want to protect the content of the script while sharing it with others.

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