<p dir="ltr">Hi devendra, it's not necessary to wrap around the characters in caeser cipher by taking a modulus like you pointed out, there are many variants of it. Anyways my actual problem is that the encrypted data is not being written into the file whereas if I don't make a call to the encrypt function then the contents are written perfectly to the files. </p>
<br><div class="gmail_quote">On 5:25pm, Fri 30-Jan-2015 devendra.aaru <<a href="mailto:devendra.aaru@gmail.com">devendra.aaru@gmail.com</a>> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Fri, Jan 30, 2015 at 6:48 AM, Kunal Baweja <span dir="ltr"><<a href="mailto:bawejakunal15@gmail.com" target="_blank">bawejakunal15@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div><div><div>Yeah I was trying something similar only but with a much simpler Caeser cipher function of my own written as below:<br><br>void encrypt(char *data, char *encrypted, size_t size)<br>{<br> unsigned int i;<br> for(i=0;i<(unsigned int)size;i++)<br> encrypted[i] = data[i] + 3;<br></div></div></div></div></blockquote><div><br></div></div></div></div><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div>This is not caesar's cipher. If your buffer contains alphabets then only you can apply caesar cipher.</div><div><br></div><div>It should be something like</div><div><br></div><div> encrypted[i] = (data[i] - 3) % 26;</div></div></div></div><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div><br></div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div><div><div> printk(KERN_INFO "%s",encrypted);<br> return;<br>}<br></div><br></div><div>So in the given code wherever u see the calls to <b>wrapfs_encrypt</b>, I have replaced with my simpler encryption function.<br></div><div><br></div>But I am not able to figure out why calling this function creates a problem, the printk() statement inside the function shows me the correctly encrypted contents but the file is still blank.<br><br></div>Thanks<br><div class="gmail_extra"><span><br clear="all"><div><div><div dir="ltr"><div><b style="font-size:small;font-family:arial"><font face="arial, helvetica, sans-serif" color="#000000">Kunal Baweja</font></b><br></div><img><br><div><div style="font-family:arial;font-size:small"><span style="color:rgb(102,102,102);font-family:arial,helvetica,sans-serif">Undergraduate B.E. (Hons.) Computer Science</span><br></div><div style="font-family:arial;font-size:small"><font face="arial, helvetica, sans-serif"><font color="#666666">Birla Institute Of Technology & Science, Pilani</font><br></font></div><div style="font-family:arial;font-size:small"><font face="arial, helvetica, sans-serif" color="#666666">K.K. Birla Goa Campus</font></div><div style="font-family:arial;font-size:small"><font style="font-weight:bold" face="arial, helvetica, sans-serif" color="#3d85c6">+91 9049655665</font></div></div></div></div></div>
<br></span><div><div><div class="gmail_quote">On Fri, Jan 30, 2015 at 4:03 PM, Saket Sinha <span dir="ltr"><<a href="mailto:saket.sinha89@gmail.com" target="_blank">saket.sinha89@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div>HI,</div><div><br></div>Kindly refer the following link that implements a minimal encryption over wrapfs.<div><a href="https://github.com/piekill/wrapfs" target="_blank">https://github.com/piekill/wrapfs</a><br><div><br></div><div>Go through the wrapfs_encrypt in wrapfs_readpage and wrapfs_decrypt in wrapfs_writepage.</div></div><div><br></div><div>Regards,</div><div>Saket Sinha</div></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div>On Fri, Jan 30, 2015 at 3:56 PM, Kunal Baweja <span dir="ltr"><<a href="mailto:bawejakunal15@gmail.com" target="_blank">bawejakunal15@gmail.com</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div><div dir="ltr"><div><div><div>Hi,<br></div>I am currently working on implementing a simple encrypted file system using a stackable file system <a href="http://wrapfs.filesystems.org/" target="_blank">WrapFS</a>. In order to do so, as I read in the <a href="http://www.fsl.cs.sunysb.edu/pipermail/wrapfs/2011-November/000058.html" target="_blank">WrapFS mailing list</a> one needs to implement address space operations, which I have done and posted on my github at <a href="https://github.com/bawejakunal/wrapfs-addresspace-operations/blob/master/mmap.c" target="_blank">this link</a> and it works fine. But now when I am trying to modify the data before being written in wrapfs_lower() function I get a blank output in files written out.<br></div>Please guide where am I going wrong in modifying the data to be written and what could be the best way to decrypt it ?<br><br></div>Thanks<span><font color="#888888"><br><div><div><br clear="all"><div><div><div><div><div dir="ltr"><div><b style="font-size:small;font-family:arial"><font face="arial, helvetica, sans-serif" color="#000000">Kunal Baweja</font></b><br></div><img><br><div><div style="font-family:arial;font-size:small"><span style="color:rgb(102,102,102);font-family:arial,helvetica,sans-serif">Undergraduate B.E. (Hons.) Computer Science</span><br></div><div style="font-family:arial;font-size:small"><font face="arial, helvetica, sans-serif"><font color="#666666">Birla Institute Of Technology & Science, Pilani</font><br></font></div><div style="font-family:arial;font-size:small"><font face="arial, helvetica, sans-serif" color="#666666">K.K. Birla Goa Campus</font></div><div style="font-family:arial;font-size:small"><font style="font-weight:bold" face="arial, helvetica, sans-serif" color="#3d85c6"><a href="tel:%2B91%209049655665" value="+919049655665" target="_blank">+91 9049655665</a></font></div></div></div></div></div>
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