Guide to Computer Forensics and Investigations - Chapter 8: Recovering Graphics Files

A comprehensive set of 1000 flashcards based on key concepts from Chapter 8 of the 'Guide to Computer Forensics and Investigations' to help students study recovering graphics files.

What are the main components of graphic files?

Digital photographs, line art, three-dimensional images, text data converted to images, and scanned replicas of printed pictures.

What are bitmap images?

Collections of dots that make up an image.

How are vector graphics described?

Graphics based on mathematical instructions that use lines instead of dots.

What are metafile graphics?

Graphics that combine both bitmap and vector graphics.

What is the purpose of graphics editors?

To enable users to create and edit graphic files.

What is the difference between bitmap and raster images?

Bitmap images are collections of individual pixels, while raster images are also collections of pixels but stored in a specific format.

What factors influence image quality?

Screen resolution and the number of color bits used per pixel.

What are the characteristics of vector graphics?

They use lines instead of dots, store calculations for drawing shapes, are smaller than bitmap files, and preserve quality when enlarged.

What is an example of a standard vector file format?

Hewlett Packard Graphics Language (.hpgl) or AutoCAD (.dxf).

Name a widely known bitmap file format.

Portable Network Graphic (.png).

What disadvantage do raw file formats have?

They are proprietary and not all image viewers can display them.

What is demosaicing?

The process of converting raw picture data to another format.

What is the Exif format used for?

To store metadata in JPEG and TIF files.

What can investigators learn from examining Exif metadata?

Details about the digital device used and the environment in which photos were taken.

What tool can be used to view Exif JPEG file metadata?

Exif Reader or IrfanView.

What is lossless compression?

A method that reduces file size without removing any data.

What is lossy compression?

A method that permanently discards bits of information.

Which compression method is better for preserving image quality?

Lossless compression.

How can digital forensics tools help locate graphics files?

By comparing image headers with good header samples and using header information for baseline analysis.

What does carving or salvaging files involve?

Recovering any type of file fragments.

What should be done if header data is partially overwritten?

Reconstruct the header to make it readable.

What is the hexadecimal header value for a standard JPEG file?

FFD8.

What are false positives in digital forensics?

Incorrect indications of the presence of JPEG files when searching for data.

What are the steps to recover a fragmented file?

Locate clusters, determine starting and ending cluster numbers, copy sectors in sequence, and rebuild the header.

What is the role of a hexadecimal editor in file analysis?

To record hexadecimal values in headers and define file types.

How can steganography be described?

A method that hides information inside image files without altering their appearance.

What are the two major forms of steganography?

Insertion and substitution.

How can hidden data in image files typically go unnoticed?

Because it is not displayed when viewing the host file in its associated program.

What tool can help detect steganography in files?

Steganalysis tools (steg tools).

What is the significance of the U.S. Copyright Office?

It provides information on what can and can’t be covered under copyright law in the U.S.

What is fair use in the context of copyright?

A guideline that allows the use of copyrighted material for noncommercial or educational purposes without compensation.

What are the three basic types of graphics files?

Bitmap, vector, and metafile.

What formats commonly compress their data?

GIF and JPEG.

What should be avoided when recovering image files to maintain image integrity?

Overwriting the original files.

What is a bitmap file format example?

Windows Bitmap (.bmp).

What are nonstandard formats used in graphics files?

Adobe Photoshop (.psd), Targa (.tga), and Scalable Vector Graphics (.svg).

What is essential to remember when analyzing unknown file formats?

The importance of knowing the purpose of each format and its data storage.

What is a characteristic of raster graphics?

They store data in grids of individual pixels.

How does vector quantization (VQ) relate to lossy compression?

It determines what data to discard based on vectors in the graphics file.

What is the main challenge when working with raw image formats?

Not all viewers can display these proprietary formats.

Why is the Internet a valuable resource for digital forensics?

It provides information about various file formats, tools, and methodologies.

What program can be used to extract metadata from recovered files?

Autopsy.

What is an important step before editing a recovered graphics file?

Open the file with an image viewer first.

What factors affect the file size of an image?

File format, compression method, and image quality.

Name an essential utility for lossless compression.

WinZip.

What does the term 'file slack' refer to in digital forensics?

Unused storage space within a disk cluster.

What should you do if an image does not display correctly after recovery?

Inspect and correct the header values manually.

What are common file extensions for bitmap graphics?

.png, .jpg, .gif, and .tif.

What is an example of a proprietary raw file format from digital cameras?

CR2 from Canon cameras.

What can be inferred from duplicate files with different hash values?

Possible evidence of steganography techniques.

What are the challenges with recovering data from unallocated space?

Time-consuming process and results are difficult to verify.

How can a file be reconstructed from fragments?

By identifying data patterns and manually assembling the file.

What is an indication that a graphics file may have been modified?

Changed file size, image quality, or file extension.

What is the standard format used to display digital device metadata?

Exchangeable Image File format (Exif).

What is the advantage of using multiple viewer programs?

To ensure compatibility with a wide range of graphic file formats.

What is the purpose of using file format identification tools?

To determine the type of unknown file formats.

What does image quality depend on in bitmap graphics?

Screen resolution and the number of color bits per pixel.

What is a key fact about vector graphics?

They preserve quality when enlarged.

What does the digital forensics process include when dealing with images?

Searching, recovering, analyzing, and inspecting image files.

What are graphical editing programs used for?

To create, modify, and edit image files.

How does steganalysis work?

By finding hidden data in image files.

What is the main type of data stored in bitmap images?

Pixels arranged in a grid.

Why might certain file formats be referred to as nonstandard?

They are not widely recognized or used compared to standard formats.

What is the main purpose of metadata in digital photography?

To provide context and details about the photograph.

What are some commonly used apps for viewing images in investigations?

IrfanView, Exif Reader, and Magnet Forensics AXIOM.

What can investigators do with the metadata extracted from an image?

Learn about the conditions under which the image was taken.

How should recovered graphics files be examined?

By comparing them with known good images to verify their integrity.

What is an implication of using digital watermarks?

They can protect copyrighted material.

What does the term 'graphics file format' refer to?

The method of storing and encoding graphic images in digital files.

What is a digital negative in photography?

The raw file format from digital cameras.

How does the process of rebuilding headers assist in file recovery?

It makes recovered files readable by graphics viewers.

What is the benefit of utilizing recovery files?

To safely store and organize fragmented data before reconstruction.

Which kind of compression do most graphics files use?

Data compression.

What is a commonly used tool for JPEG file integrity verification?

Autopsy.

What are the steps involved in reconstructing a graphics file from fragments?

Locate fragments, copy in order, and build the header.

What major advantage do vector graphics have over bitmap images?

Quality preservation when enlarged.

What are some tools used to detect steganography?

Steganalysis tools (steg tools) and software for image analysis.

Why is analyzing graphics file headers important?

To identify file types and integrity.

How can file extensions provide clues about a file's format?

They indicate what type of format the file is likely to be.

What is the preserved component in raw photography files?

The highest quality version of the image data.

What is a critical aspect when recovering image files?

Avoiding any alteration to the original data.

What does Lempel-Ziv-Welch coding apply to?

Lossless data compression methods.

What factor affects the readability of a recovered graphics file?

The condition of its header.

What strategy should be used for examining fragmented files?

Carefully reconstructing using known patterns.

What is a significant feature of metafile graphics?

They combine both raster (bitmap) and vector graphics benefits.

In what context is copyright particularly relevant for graphic files?

When analyzing and using digital images for commercial purposes.

What is typically the first step in digital forensics regarding image files?

Planning the examination process.

How can image viewer tools assist investigators?

By allowing access to and viewing of various image formats.

What do .pst files typically contain?

Data for Adobe Photoshop documents.

What are the key characteristics of graphics file formats?

Standards for how graphics data is stored and interpreted.

What is the goal of compressing data in graphics file formats?

To reduce file size for storage efficiency.

Why is it recommended to have multiple graphics file viewers?

Not all viewers support all image formats.

What constitutes a fragment in the context of graphics files?

A piece of a larger file that may have been deleted or corrupted.

What is the usual outcome of lossy compression?

Reduced file size at the cost of some image quality.

What digital tool can help identify graphics file formats?

Hexadecimal editor.

What might be a consequence of using digital watermarks in images?

Potential legal complications regarding copyright.

How is vector graphic data stored?

As mathematical formulas representing shapes and lines.

What notable difference exists between standard and nonstandard graphics file formats?

Standard formats are widely recognized, while nonstandard formats are less common.

What is a common software utility used for lossless file compression?

WinZip or StuffIt.

What should be analyzed when the integrity of a recovered image file is in question?

The file's header and metadata.