16 Replies to “Encrypt & Decrypt Files With Password Using OpenSSL”

1. error:20074002:BIO routines:FILE_CTRL:system lib:bss_file.c:400:

2. openssl enc -aes-256-cbc -d -in /Users/huntert/Desktop/IMPT.dmg -out /Users/huntert/Desktop/IMPT.dmg
   enter aes-256-cbc encryption password:
   Verifying – enter aes-256-cbc encryption password:

   When I tried to decrypt it, I received the folllowing messages:
   enter aes-256-cbc decryption password:
   error reading input file

   I should’ve been more cautious and tried it on a rubbish file. Lesson learned.

3. -pass pass:
   or
   -pass file:
   works for ecoding & decoding

4. I have a problem to decrypt a file
   I have encrypted my file after I used this file in matlab (modulation ..) and then I cannot decrypt the extracted file from matlab
   error is ” error reading file ”
   what I have to do ?

5. thank you for this, very helpful.
   one thing I ask, where do I get the openssl (I assume executable) from to run the encrypt and decrypt?
   Neil

6. If you want a solution i’m here
   Thanks
   Kurtis

7. But how do we do this programmatically? I’ve a situation where I need to use a password to login to a server programmatically. We cannot hard code the password to decrypt the file. One option I know is to store the password in a vault but that takes too long/expensive to implement. Please suggest. thanks

   1. I used to deploy encrypted bash programs to production using openssl.
      I suggest looking at https://linuxconfig.org/using-openssl-to-encrypt-messages-and-files-on-linux
      Or,
      If your program is compiled code, then why not encrypt secret in a file (manually) then decrypt it in your code into a variable? Then, you can programmatically use it as input to your authentication process.
      Hope this helps.

      Here is a sample code in GNU-C:

      //------------------------------------
      int main (int argc, char *argv[], char *envp[]) {
        char *cmdstr = (char *) malloc (254);
        memset(cmdstr, '\0', sizeof(254));
        /* build the command string for encryption */
        strcpy(cmdstr, "openssl enc -aes-256-cbc -in file.txt -out file.txt.enc -iter 29 -pass pass:mysecret");
      
        /* encrypt */
        if (run_my_script (cmdstr) == -1)
          fprintf(stderr, "Failed to encrypt file\n");
      
        /* rebuilt the command string for decryption */
        strcpy(cmdstr, "openssl enc -aes-256-cbc -d -in file.txt.enc -out decrypted_file.txt -iter 29 -pass pass:mysecret");
      
        /* decrypt */
        if (run_my_script (cmdstr) == -1)
          fprintf(stderr, "Failed to decrypt file.txt.enc\n");
      
        free(cmdstr);
      
        return 0;
      }
      
      int run_my_script (const char *command) {
         int status;
         pid_t pid;
         pid = fork ();
         if (pid == 0) {
            /* This is the child process.  Execute the shell command. */
            execl (SHELL, SHELL, "-c", command, NULL);
            _exit (EXIT_FAILURE);
         }
         else if (pid < 0)
            /* The fork failed.  Report failure.  */
            status = -1;
         else
            /* This is the parent process.  Wait for the child to complete.  */
            if (waitpid (pid, &status, 0) != pid)
               status = -1;
         return status;
      }

8. e.g.
   ENCRYPT (interactive):

   openssl enc -aes-256-cbc -in file.txt.enc -out file.txt  -iter 29 -k PASS

   DECRYPT (interactive):

   openssl enc -aes-256-cbc -d -in file.txt.enc -out file.txt -iter 29 -k PASS

   ENCRYPT (non-interactive):

   openssl enc -aes-256-cbc -in file.txt.enc -out file.txt  -iter 29 -pass pass:mysecret

   DECRYPT (non-interactive):

   openssl enc -aes-256-cbc -d -in file.txt.enc -out file.txt -iter 29 -pass pass:mysecret