Client Side Online Decryption of Text Files Using git instaweb
NOTE: This is a dirty hack only. It utilizes git-instaweb to show the sparkleshare git online in a browser and adds decrypting functionality for text files to it. Follow the tutorial on your own risk!
1) You need a encrypted sparkleshare share (here: test-crypto)
2) navigate to the share folder (here: /home/storage/test-crypto/)
3) start git-instaweb by typing:
root@box:/home/storage/test-crypto# git-instaweb -p 12345
4) go to /home/storage/test-crypto/.git/gitweb/ and add a file named "decrypt.js" with the following content:
if(!decrypted || decrypted == "") {
alert("Wrong password!");
return(-1);
}
decrypted = decrypted.toString(CryptoJS.enc.Utf8);
var splitted = decrypted.split("\n");
var resulting = "";
for(var i=0; i<splitted.length; i++) {
resulting += "<div class=\"pre\"><a id=\"" + (i+1) + "\" href=\"#" + (i+1) + "\" class=\"linenr\">" + a(i+1, 4) + "</a> " + splitted[i] + "</div>"
}
document.getElementById("page_body").innerHTML = resulting;
}
function a(b, howmany) {
b = "" + b;
var r = ""
for(var i=b.length; i< howmany; i++)
r+=" ";
return(r + b);
}
5) apply the following patch to /home/storage/test-crypto/.git/gitweb/gitweb.cgi:
<head>
+
+<script src="decrypt.js" type="text/javascript"></script>
+<script src="http://crypto-js.googlecode.com/svn/tags/3.0.2/build/rollups/aes.js"></script>
+
<meta http-equiv="content-type" content="$content_type; charset=utf-8"/>
<meta name="generator" content="gitweb/$version git/$git_version$mod_perl_version"/>
<meta name="robots" content="index, nofollow"/>
@@ -4338,8 +4334,7 @@
"<div class=\"title\">$hash</div>\n";
}
git_print_page_path($file_name, "blob", $hash_base);
+ print "<div id=\"page_body\" class=\"page_body\">\n";
+ my $blobcontent;
- print "<div class=\"page_body\">\n";
if ($mimetype =~ m!^image/!) {
print qq!<img type="$mimetype"!;
if ($file_name) {
@@ -4352,7 +4347,6 @@
} else {
my $nr;
while (my $line = <$fd>) {
+ $blobcontent = $blobcontent . $line;
chomp $line;
$nr++;
$line = untabify($line);
@@ -4362,7 +4356,7 @@
}
close $fd
or print "Reading blob failed.\n";
+ printf "</div><button onclick=\"decrypt_blob('%s')\">decrypt</button>", $blobcontent;
- print "</div>";
git_footer_html();
}
6) You are done. Navigate your browser to http://your-ip:12345 and open the blob view of an encrypted text file and at the bottom there is a decrypt button. Use it to decrypt the text live in your browser.