gg_stegano

README

Steganography implementation

Write/Read text into/from images.

This module is a fork and adjustment from original work of Auyer https://github.com/auyer/steganography

Documentation

Index

• type SteganoHelper
  • func (instance *SteganoHelper) Decode(msgLen uint32, pictureInputFile image.Image) (message []byte)
  • func (instance *SteganoHelper) DecodeMessageBytes(img image.Image, key []byte) ([]byte, error)
  • func (instance *SteganoHelper) DecodeMessageBytesFromBytes(data []byte, key []byte) ([]byte, error)
  • func (instance *SteganoHelper) DecodeMessageBytesFromFile(filename string, key []byte) ([]byte, error)
  • func (instance *SteganoHelper) Encode(writeBuffer *bytes.Buffer, pictureInputFile image.Image, message []byte) error
  • func (instance *SteganoHelper) EncodeMessageBytes(img image.Image, msg, key []byte) (*bytes.Buffer, error)
  • func (instance *SteganoHelper) EncodeMessageBytesFromBytes(data []byte, message, key []byte) (*bytes.Buffer, error)
  • func (instance *SteganoHelper) EncodeMessageBytesFromFile(filename string, message, key []byte) (*bytes.Buffer, error)
  • func (instance *SteganoHelper) EncodeNRGBA(writeBuffer *bytes.Buffer, rgbImage *image.NRGBA, message []byte) error
  • func (instance *SteganoHelper) GetMessageSizeFromFile(filename string) uint32
  • func (instance *SteganoHelper) GetMessageSizeFromImage(pictureInputFile image.Image) (size uint32)
  • func (instance *SteganoHelper) MaxEncodeSize(img image.Image) uint32
  • func (instance *SteganoHelper) MaxEncodeSizeFromFile(filename string) uint32
  • func (instance *SteganoHelper) Verify(img image.Image, message []byte) bool
  • func (instance *SteganoHelper) VerifyNRGBA(img *image.NRGBA, message []byte) bool

Types

type SteganoHelper

type SteganoHelper struct {
}

var Stegano *SteganoHelper

func (*SteganoHelper) Decode

func (instance *SteganoHelper) Decode(msgLen uint32, pictureInputFile image.Image) (message []byte)

Decode gets messages from pictures using LSB steganography, decode the message from the picture and return it as a sequence of bytes It wraps EncodeNRGBA making the conversion from image.Image to image.NRGBA

Input:
	msgLen uint32 : size of the message to be decoded
	pictureInputFile image.Image : image data used in decoding
Output:
	message []byte decoded from image

func (*SteganoHelper) DecodeMessageBytes

func (instance *SteganoHelper) DecodeMessageBytes(img image.Image, key []byte) ([]byte, error)

func (*SteganoHelper) DecodeMessageBytesFromBytes

func (instance *SteganoHelper) DecodeMessageBytesFromBytes(data []byte, key []byte) ([]byte, error)

func (*SteganoHelper) DecodeMessageBytesFromFile

func (instance *SteganoHelper) DecodeMessageBytesFromFile(filename string, key []byte) ([]byte, error)

func (*SteganoHelper) Encode

func (instance *SteganoHelper) Encode(writeBuffer *bytes.Buffer, pictureInputFile image.Image, message []byte) error

Encode encodes a given string into the input image using the least significant bit encryption (LSB steganography) The minimum image size is 23 pixels It wraps EncodeNRGBA making the conversion from image.Image to image.NRGBA

Input:
	writeBuffer *bytes.Buffer : the destination of the encoded image bytes
	message []byte : byte slice of the message to be encoded
	pictureInputFile image.Image : image data used in encoding
Output:
	bytes buffer ( io.writter ) to create file, or send data.

func (*SteganoHelper) EncodeMessageBytes

func (instance *SteganoHelper) EncodeMessageBytes(img image.Image, msg, key []byte) (*bytes.Buffer, error)

func (*SteganoHelper) EncodeMessageBytesFromBytes

func (instance *SteganoHelper) EncodeMessageBytesFromBytes(data []byte, message, key []byte) (*bytes.Buffer, error)

func (*SteganoHelper) EncodeMessageBytesFromFile

func (instance *SteganoHelper) EncodeMessageBytesFromFile(filename string, message, key []byte) (*bytes.Buffer, error)

func (*SteganoHelper) EncodeNRGBA

func (instance *SteganoHelper) EncodeNRGBA(writeBuffer *bytes.Buffer, rgbImage *image.NRGBA, message []byte) error

EncodeNRGBA encodes a given string into the input image using the least significant bit encryption (LSB steganography) The minimum image size is 24 pixels for one byte. For each additional byte, it is necessary 3 more pixels.

Input:
	writeBuffer *bytes.Buffer : the destination of the encoded image bytes
	pictureInputFile image.NRGBA : image data used in encoding
	message []byte : byte slice of the message to be encoded
Output:
	bytes buffer ( io.writter ) to create file, or send data.

func (*SteganoHelper) GetMessageSizeFromFile

func (instance *SteganoHelper) GetMessageSizeFromFile(filename string) uint32

func (*SteganoHelper) GetMessageSizeFromImage

func (instance *SteganoHelper) GetMessageSizeFromImage(pictureInputFile image.Image) (size uint32)

GetMessageSizeFromImage gets the size of the message from the first four bytes encoded in the image

func (*SteganoHelper) MaxEncodeSize

func (instance *SteganoHelper) MaxEncodeSize(img image.Image) uint32

MaxEncodeSize given an image will find how many bytes can be stored in that image using least significant bit encoding ((width * height * 3) / 8 ) - 4 The result must be at least 4,

func (*SteganoHelper) MaxEncodeSizeFromFile

func (instance *SteganoHelper) MaxEncodeSizeFromFile(filename string) uint32

func (*SteganoHelper) Verify

func (instance *SteganoHelper) Verify(img image.Image, message []byte) bool

func (*SteganoHelper) VerifyNRGBA

func (instance *SteganoHelper) VerifyNRGBA(img *image.NRGBA, message []byte) bool