Jul 29, 2011 · With file locking you can specify that your process is the only one allowed to access the file WHILE it is running. All locks are freed once your program terminate. Acess control, as you need it, is part of the operating system (ACLs, read/ write permissions) http://linux.die.net/man/2/flock.

Jan 7, 2021 · The following example encrypts a data file. The example interactively requests the name of the file that contains plaintext to be encrypted and the name of a file where the encrypted data is to be written.

Jun 14, 2010 · Strings in executable file are in plain text, anyone with a text editor can easily look at your password. A not so secure, but would trample some people, is to store the encrypted string instead. So, basically: pass = getPassFromUser(); encpass = myHashingFunction(pass); return enc == encpass;

Mar 20, 2025 · Write a C program to encrypt a file using a simple substitution cipher and save the encrypted file. Write a C program to encrypt a file using XOR encryption with a user-provided key. Write a C program to encrypt the contents of a file line by …

Jun 30, 2021 · Link against libsodium and use its secretbox to encrypt a buffer of file contents. You'll need to derive a key from the user's password. Alternatively use Monocypher which is more flexible but a bit more complex. It has its own kind of secretbox.

Mar 28, 2012 · Just store the password in hashed form. Often, the method is to use MD5 + salt (here is a description and some sample PHP code). What you can do is instead of transmitting or storing the plaintext password, just hash the user input and check the hash against the stored hash value. Matching hashes corresponds to matching passwords. EDIT

Let us create a simple File Security System using C programming file handling and other basic concepts. A File Security System is a console application that can be used to prevent unauthorized access to a file. It prompts the user to enter a password before he/she can access the particular file.

Jun 1, 2022 · Caesar cipher logic with "key = 3" is used to encrypt the data file. Following C Programming File Management functions are used to encrypt content of Login.txt file: fopen () fgetc () fputc...

To encrypt a file in C programming, you have to open that file and start reading the file character by character. At the time of reading, create some algorithm to encrypt the content of the file, and place the content in a temporary file, character by character.

Oct 1, 2021 · Secure your C programs with password protection. Follow this tutorial on rrtutors.com to implement authentication before executing a C program.