Error level analysis (ELA)

• “Error level analysis (ELA) works by intentionally resaving the image at a known error rate, such as 95%, and then computing the difference between the images.If there is virtually no change, then the cell has reached its local minima for error at that quality level. However, if there is a large amount of change, then the pixels are not at their local minima and are effectively original.” 

This implemenation makes use of the Python Image Library, and libjpeg (v6.2.0-882.2). ELA is carried out at 95%. Resulting ELA images have had their brightness enhanced to further seperate differences out.
http://www.errorlevelanalysis.com/

• This free research service is public

http://fotoforensics.com/

• Photo Forensics: Detect Photoshop Manipulation with Error Level Analysis

Error Level Analysis is a forensic method to identify portions of an image with a different level of compression.
The technique could be used to determine if a picture has been digitally modified. To better understand the techniques, it’s necessary to deepen the JPEG compression technique.

JPEG (Joint Photographic Experts Group) is a method of lossy compression for digital images.

The Image Error Level Analyzer
The Image Error Level Analyzer in an online tool that implements an ELA algorithm. By using it, it’s possible to rapidly discover image manipulation. The web tool is based on the Python Image Library and the libjpeg library (v6.2.0-822.2). The verification process consists of successive resaves of the image at a predefined quality. The resulting picture is compared with the original one.

The rainbowing technique
Rainbowing indicates the visible separation between the luminance and chrominance channels as blue,purple and red.
Picture modification with commercial tools such as Photoshop or Gimp can introduce distinct rainbowing pattern surfaces that have near-uniform coloring
High-quality camera photos may also include a rainbowing effect along uniformly colored surfaces.
Beware that the presence of rainbowing may only mean that an Adobe product, like Photoshop or Lightroom, was used to save the image. It may not represent proof of an intentional image alteration.
https://resources.infosecinstitute.com/error-level-analysis-detect-image-manipulation/#gref

• This is the home of Pillow, the friendly PIL fork. PIL is the Python Imaging Library. If you have ever worried or wondered about the future of PIL, please stop. We're here to save the day.

https://python-pillow.org/

• To me, the "realistic" claims for these images does not match the quality. (I've been seeing altered and computer-generated images for years. Many of those other approaches are much better than this.) Instead, the impressive parts are the speed, size, and detail. Each time you reload a picture on their site, they create a brand new image from scratch. There is no 3D modeling or manual editing. With more training and some rule adjustments, I'm sure they could fix their aesthetics issues. And they can probably do this without any impact to their post-training speed.

However, I also expect to see these images being used for scams that involve images. For example, catfishing uses photos of people to lure victims. Many catfishers grab photos from Facebook or other social media sites. But there is always the risk of being discovered through a reverse image search. With these completely computer-generated people, there is no risk of finding a stolen social media photo.
Fake dating sites could also use this system. Ashley Madison had thousands of fictional accounts for female users; 99% of their profiles for women were fake and designed to attract paying male users. Most of their fake profiles used low quality or distorted images of women
I'm actually a little surprised that I haven't yet seen fake IDs with these pictures. But it's only a matter of time before they show up. Fake accounts on services like Facebook and Twitter work best when there's a profile image, and these pictures are good enough for that. LinkedIn requires "real photos", but I'm sure these fakes would be acceptable. Really, these pictures can be used almost anywhere a headshot could be used
http://www.hackerfactor.com/blog/

the directories dot and dot-dot

Verify on your system that the directories dot and dot-dot are not the same, except in the root directory

the root directory
vagrant@control01:/$ ls -ail
total 97
      2 drwxr-xr-x  24 root    root     4096 Feb 21 20:28 .
      2 drwxr-xr-x  24 root    root     4096 Feb 21 20:28 ..


the directories dot and dot-dot are not the same
vagrant@control01:~$ ls -ail
total 64
3145730 drwxr-xr-x 5 vagrant vagrant 4096 Feb 22 05:08 .
3145729 drwxr-xr-x 3 root    root    4096 Aug 24 08:48 ..

3145730
The first is the directory itself (so it contain some data about directory permissions)
3145729
the second is the parent directory


The UNIX System guarantees that every process has a unique numeric identifier called the process ID. The process ID is always a non-negative integer


Directories cannot have hard links
Unix permits you to give files many names ("links"),but, not directories
You are not allowed to create a hard link to a directory
Each directory inode is allowed to appear once in exactly one parent directory and no more
every sub-directory only has one parent directory, and that means the special name ".." (dot dot) in a sub-directory always refers unambiguously to its unique parent directory.

Each subdirectory adds one to the link count

A directory may have sub-directories. Since the special name ".." (dot dot) in every one of those sub-directories is a link to the inode number of the parent directory, the link count of the parent directory is increased by one for every sub-directory the parent contains. (Remember - the link count counts how many name-inode maps point to this inode, and that includes the special "." (dot) and ".." (dot dot) name-inode maps!) A directory with five sub-directories will show a link count of 2+5=7.

• What is Sticky Bit?

The sticky bit is used to indicate special permissions for files and directories.
If a directory with sticky bit enabled will restrict deletion of the file inside it.
It can be removed by root, owner of the file or who have to write permission on it.
This is useful for publically accessible directories like /tmp.

What is SUID (setuid)?
If SUID bit is set on a file and a user executed it. The process will have the same rights as the owner of the file being executed.
For example: passwd command have SUID bit enabled. When a normal user changes his password this script update few system files like /etc/passwd and /etc/shadow which can’t be updated by non-root account. So that passwd command process always run with root user rights.

$ ls -lrt /usr/bin/passwd
-rwsr-xr-x 1 root root 54256 May 16  2017 /usr/bin/passwd
$ ls -lrt /etc/shadow
-rw-r----- 1 root shadow 994 Aug 24  2018 /etc/shadow
$ ls -lrt /bin/su
-rwsr-xr-x 1 root root 40128 May 16  2017 /bin/su

https://tecadmin.net/understanding-sticky-bit-suid-and-sgid-in-linux/

If You’re Not Interviewing Anywhere Else

• If You’re Not Interviewing Anywhere Else

You know not to say this directly, but how do you get around it? The trick is to simply choose to answer a different question. Instead of responding with your lack of other interviews, let your interviewer know what types of positions and companies you’ve been applying to.
https://www.themuse.com/advice/how-to-answer-what-other-companies-are-you-interviewing-with

• Let’s start by considering why hiring managers ask this question in the first place. There are three big-picture reasons.

To gauge their own timeline.
Your hiring manager may want to know where in the hiring process you are with other companies so that they can speed up the decision-making process on their end if necessary. They also may not want to invest much more time into your candidacy if they sense that you are close to accepting an offer elsewhere (particularly if they were not all that keen on you to begin with).
To assess the supply and demand in the market.
The hiring manager may be asking this tough interview question to try to get a sense for how many similar positions are open right now. That can impact the economics of the offer – in your favor, or in favor of the company.
To get a sense for your popularity.
Sometimes, hiring managers like to get external confirmation that you are a valuable and in-demand candidate. This may not make logical sense–after all, if they are interviewing you, there must be something about your background they like! And yet, sometimes they want to hear it from other companies.
https://www.topresume.com/career-advice/how-to-answer-where-else-are-you-interviewing

• To demonstrate your commitment and still make it clear that you’re a valuable candidate who is already on the radar of other employers, be enthusiastic while showing that you do have other opportunities.

https://www.wayup.com/guide/answer-companies-interviewing/

• “I’m actively interviewing and I’m talking with a number of early stage technology companies like yours

If they press you for specific company names:
Do NOT give them company names.
https://careersidekick.com/what-other-companies-are-you-interviewing-with/