Steganography in Rust

An introduction for what steganography is, how it works for images and most importantly how it is implemented in rust inside the stegano-cli tool.

Transcript

1. Steganography in Rust hiding secrets in images Sven Assmann @5422m4n /sassman
2. I do lot of business application development with web technologies and big databases Sometimes I also write about learning rust Hi, I’m Sven @5422m4n /sassman
3. tweeting coding writing @5422m4n /sassman twitter.com/@5422m4n github.com/sassman dev.to/sassman
4. What is Steganography? in bloomy words: “the art of hiding information behind something” speaking more tech: “hiding data in image, audio or video data” @5422m4n /sassman
5. Cryptography vs Steganography hiding information nobody should know Alice and Bob are communicating protects the sender and recipient inaccessible information anyone can know Alice and Bob are communicating protects the message Steganography can be combined with Cryptography @5422m4n /sassman
6. About Images width height Pixel @5422m4n /sassman
7. About Pixel Pixel Red Green Blue Transparency / Alpha @5422m4n /sassman
8. About Colors R: 0xE7 G: 0xA6 B: 0x29 R: 0xE6 G: 0xA7 B: 0x28 Can you tell the difference? @5422m4n /sassman
9. Least Significant Bit (LSB) R: 0xE7 G: 0xA6 B: 0x29 R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 0xE6 G: 0xA7 B: 0x28 R: 1110 0110 G: 1010 0111 B: 0010 1000 1 bit 1 bit 1 bit - + - @5422m4n /sassman
10. About Data R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0111 G: 1010 0110 B: 0010 1001 @5422m4n /sassman
11. About Data R: 1110 0110 G: 1010 0110 B: 0010 1000 R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0111 G: 1010 0110 B: 0010 1001 @5422m4n /sassman
12. About Data R: 1110 0110 G: 1010 0110 B: 0010 1000 R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0111 G: 1010 0110 B: 0010 1000 R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0111 G: 1010 0110 B: 0010 1001 @5422m4n /sassman
13. About Data R: 1110 0110 G: 1010 0110 B: 0010 1000 R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0111 G: 1010 0110 B: 0010 1000 R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0111 G: 1010 0110 B: 0010 1001 @5422m4n /sassman
14. About Data R: 1110 0110 G: 1010 0110 B: 0010 1000 R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0111 G: 1010 0110 B: 0010 1000 R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0111 G: 1010 0110 B: 0010 1001 @5422m4n /sassman
15. About Data R: 1110 0110 G: 1010 0110 B: 0010 1000 R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0111 G: 1010 0110 B: 0010 1000 R: 1110 0110 G: 1010 0110 B: 0010 1000 R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0111 G: 1010 0110 B: 0010 1001 @5422m4n /sassman
16. About Data R: 1110 0110 G: 1010 0110 B: 0010 1000 R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0111 G: 1010 0110 B: 0010 1000 R: 1110 0110 G: 1010 0110 B: 0010 1000 R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0110 G: 1010 0111 B: 0010 1001 @5422m4n /sassman
17. About Data R: 1110 0110 G: 1010 0110 B: 0010 1000 R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0111 G: 1010 0110 B: 0010 1000 R: 1110 0110 G: 1010 0110 B: 0010 1000 R: 1110 0110 G: 1010 0110 B: 0010 1001 R: 1110 0110 G: 1010 0111 B: 0010 1001 @5422m4n /sassman
18. About Data R: 1110 0110 G: 1010 0110 B: 0010 1000 R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0111 G: 1010 0110 B: 0010 1000 R: 1110 0110 G: 1010 0110 B: 0010 1000 R: 1110 0110 G: 1010 0110 B: 0010 1000 R: 1110 0110 G: 1010 0111 B: 0010 1001 @5422m4n /sassman
19. R: 1110 0110 G: 1010 0110 B: 0010 1000 What about the end of data? How do we end the message? R: 1110 0110 G: 1010 0110 B: 0010 1000 R: 1110 0111 G: 1010 0110 B: 0010 1000 R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0110 G: 1010 0110 B: 0010 1000 R: 1110 0110 G: 1010 0111 B: 0010 1001 R: 1110 0110 G: 1010 0110 B: 0010 1000 @5422m4n /sassman
20. R: 1110 0111 G: 1010 0110 B: 0010 1000 R: 1110 0110 G: 1010 0111 B: 0010 1000 What about the end of data? R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0110 G: 1010 0110 B: 0010 1000 “Zero out” the LSB for all Pixel Terminate the “Payload” with a marker byte sequence (like zip) Put the size of “Payload” at first (like UDP packages) R: 1110 0110 G: 1010 0110 B: 0010 1000 R: 1110 0111 G: 1010 0110 B: 0010 1000 R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0110 G: 1010 0110 B: 0010 1000 R: 1110 0110 G: 1010 0111 B: 0010 1001 R: 1110 0110 G: 1010 0110 B: 0010 1000 @5422m4n /sassman
21. R: 1110 0111 G: 1010 0110 B: 0010 1000 R: 1110 0110 G: 1010 0111 B: 0010 1000 What about the end of data? R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0110 G: 1010 0110 B: 0010 1000 “Zero out” the LSB for all Pixel Terminate the “Payload” with a marker byte sequence (like zip) Put the size of “Payload” at first (like UDP packages) R: 1110 0110 G: 1010 0110 B: 0010 1000 R: 1110 0111 G: 1010 0110 B: 0010 1000 R: 1110 0111 G: 1010 0110 B: 0010 1001 R: 1110 0110 G: 1010 0110 B: 0010 1000 R: 1110 0110 G: 1010 0111 B: 0010 1001 R: 1110 0110 G: 1010 0110 B: 0010 1000 @5422m4n /sassman
22. Architecture @5422m4n /sassman
23. Finally Code @5422m4n /sassman
24. use stegano_core::{SteganoCore, SteganoEncoder, SteganoDecoder, Hide, Unveil}; #[test] fn should_hide_and_unveil_one_text_file() -> Result<()> { SteganoCore::encoder() .hide_file("Cargo.toml") .use_carrier_image("resources/plain/carrier-image.png") .write_to("/tmp/image-with-a-file-inside.png") .hide(); SteganoCore::decoder() .use_source_image("/tmp/image-with-a-file-inside.png") .write_to_folder("/tmp/") .unveil(); assert_eq_file_content( "/tmp/Cargo.toml".as_ref(), "Cargo.toml".as_ref(), "Unveiled data did not match the original content”, ); Ok(()) } @5422m4n /sassman
25. use stegano_core::{SteganoCore, SteganoEncoder, SteganoDecoder, Hide, Unveil}; #[test] fn should_hide_and_unveil_one_text_file() -> Result<()> { SteganoCore::encoder() .hide_file("Cargo.toml") .use_carrier_image("resources/plain/carrier-image.png") .write_to("/tmp/image-with-a-file-inside.png") .hide(); SteganoCore::decoder() .use_source_image("/tmp/image-with-a-file-inside.png") .write_to_folder("/tmp/") .unveil(); assert_eq_file_content( "/tmp/Cargo.toml".as_ref(), "Cargo.toml".as_ref(), "Unveiled data did not match the original content”, ); Ok(()) } pub struct SteganoEncoder { target: Option<String>, carrier: Option<RgbaImage>, message: Message, } @5422m4n /sassman
26. use stegano_core::{SteganoCore, SteganoEncoder, SteganoDecoder, Hide, Unveil}; #[test] fn should_hide_and_unveil_one_text_file() -> Result<()> { SteganoCore::encoder() .hide_file("Cargo.toml") .use_carrier_image("resources/plain/carrier-image.png") .write_to("/tmp/image-with-a-file-inside.png") .hide(); SteganoCore::decoder() .use_source_image("/tmp/image-with-a-file-inside.png") .write_to_folder("/tmp/") .unveil(); assert_eq_file_content( "/tmp/Cargo.toml".as_ref(), "Cargo.toml".as_ref(), "Unveiled data did not match the original content”, ); Ok(()) } pub struct SteganoEncoder { target: Option<String>, carrier: Option<RgbaImage>, message: Message, } pub struct SteganoDecoder { input: Option<RgbaImage>, output: Option<String>, } @5422m4n /sassman
27. use stegano_core::{SteganoCore, SteganoEncoder, SteganoDecoder, Hide, Unveil}; #[test] fn should_hide_and_unveil_one_text_file() -> Result<()> { SteganoCore::encoder() .hide_file("Cargo.toml") .use_carrier_image("resources/plain/carrier-image.png") .write_to("/tmp/image-with-a-file-inside.png") .hide(); SteganoCore::decoder() .use_source_image("/tmp/image-with-a-file-inside.png") .write_to_folder("/tmp/") .unveil(); assert_eq_file_content( "/tmp/Cargo.toml".as_ref(), "Cargo.toml".as_ref(), "Unveiled data did not match the original content”, ); Ok(()) } @5422m4n /sassman
28. impl Hide for SteganoEncoder { fn hide(&mut self) -> &Self { let mut img = self.carrier.as_mut().unwrap(); let mut dec = LSBCodec::new(&mut img); let buf: Vec<u8> = (&self.message).into(); dec.write_all(&buf[..]) .expect("Failed to hide data in carrier image."); // ... self.carrier .as_mut() .expect("Image was not there for saving.") .save(self.target.as_ref().unwrap()) .expect("Failed to save final image"); self } } @5422m4n /sassman
29. impl Hide for SteganoEncoder { fn hide(&mut self) -> &Self { let mut img = self.carrier.as_mut().unwrap(); let mut dec = LSBCodec::new(&mut img); let buf: Vec<u8> = (&self.message).into(); dec.write_all(&buf[..]) .expect("Failed to hide data in carrier image."); // ... self.carrier .as_mut() .expect("Image was not there for saving.") .save(self.target.as_ref().unwrap()) .expect("Failed to save final image"); self } } pub struct Message { pub header: ContentVersion, pub files: Vec<(String, Vec<u8>)>, pub text: Option<String>, } @5422m4n /sassman
30. impl Hide for SteganoEncoder { fn hide(&mut self) -> &Self { let mut img = self.carrier.as_mut().unwrap(); let mut dec = LSBCodec::new(&mut img); let buf: Vec<u8> = (&self.message).into(); dec.write_all(&buf[..]) .expect("Failed to hide data in carrier image."); // ... self.carrier .as_mut() .expect("Image was not there for saving.") .save(self.target.as_ref().unwrap()) .expect("Failed to save final image"); self } } @5422m4n /sassman
31. impl<'img> Write for LSBCodec<'img> { fn write(&mut self, buf: &[u8]) -> Result<usize> { let carrier = &mut self.subject; let (width, height) = carrier.dimensions(); let mut bit_iter = BitReader::endian( Cursor::new(buf), LittleEndian, ); let mut bits_written = 0; for x in 0..width { for y in 0..height { let image::Rgba(mut rgba) = carrier.get_pixel(x, y); for c in 0..3 as usize { rgba[c] = bit_wave(rgba[c], bit_iter.read_bit()); bits_written += 1; } carrier.put_pixel(x, y, Rgba(rgba)); } } Ok((bits_written / 8) as usize) } } @5422m4n /sassman
32. impl<'img> Write for LSBCodec<'img> { fn write(&mut self, buf: &[u8]) -> Result<usize> { let carrier = &mut self.subject; let (width, height) = carrier.dimensions(); let mut bit_iter = BitReader::endian( Cursor::new(buf), LittleEndian, ); let mut bits_written = 0; for x in 0..width { for y in 0..height { let image::Rgba(mut rgba) = carrier.get_pixel(x, y); for c in 0..3 as usize { rgba[c] = bit_wave(rgba[c], bit_iter.read_bit()); bits_written += 1; } carrier.put_pixel(x, y, Rgba(rgba)); } } Ok((bits_written / 8) as usize) } } @5422m4n /sassman
33. impl<'img> Write for LSBCodec<'img> { fn write(&mut self, buf: &[u8]) -> Result<usize> { let carrier = &mut self.subject; let (width, height) = carrier.dimensions(); let mut bit_iter = BitReader::endian( Cursor::new(buf), LittleEndian, ); let mut bits_written = 0; for x in 0..width { for y in 0..height { let image::Rgba(mut rgba) = carrier.get_pixel(x, y); for c in 0..3 as usize { rgba[c] = bit_wave(rgba[c], bit_iter.read_bit()); bits_written += 1; } carrier.put_pixel(x, y, Rgba(rgba)); } } Ok((bits_written / 8) as usize) } } #[inline] fn bit_wave(byte: u8, bit: Result<bool>) -> u8 { let byt = match bit { Err(_) => byte, Ok(byt) => if byt { 1 } else { 0 } }; (byte & 0xFE) | byt } @5422m4n /sassman
34. impl<'img> Write for LSBCodec<'img> { fn write(&mut self, buf: &[u8]) -> Result<usize> { let carrier = &mut self.subject; let (width, height) = carrier.dimensions(); let mut bit_iter = BitReader::endian( Cursor::new(buf), LittleEndian, ); let mut bits_written = 0; for x in 0..width { for y in 0..height { let image::Rgba(mut rgba) = carrier.get_pixel(x, y); for c in 0..3 as usize { rgba[c] = bit_wave(rgba[c], bit_iter.read_bit()); bits_written += 1; } carrier.put_pixel(x, y, Rgba(rgba)); } } Ok((bits_written / 8) as usize) } } #[inline] fn bit_wave(byte: u8, bit: Result<bool>) -> u8 { let byt = match bit { Err(_) => byte, Ok(byt) => if byt { 1 } else { 0 } }; (byte & 0xFE) | byt } R: 1110 0111 G: 1010 0110 B: 0010 1000 @5422m4n /sassman
35. Demo @5422m4n /sassman
36. @5422m4n /sassman github.com/steganogram www.stegano.org/
37. Q & A @5422m4n /sassman