Graphic interchange format (GIF) image encryption method based on compressed encoding

A technology of compression coding and encryption method, which is applied in the field of digital image encryption, can solve the problems of great impact on security, inability to adjust encryption strength adaptively, increase ciphertext volume, etc., achieve good security, maintain format compatibility, and The effect of encryption efficiency

Active Publication Date: 2013-03-13
重庆艾博特科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, the existing encryption algorithm based on LZW encoding cannot provide adaptive adjustment of the corresponding encryption strength according to the statistical characteristics of the image plaintext data.
[0006] Secondly, at present, some encryption algorithms based on LZW encoding, when the encryption...

Method used

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  • Graphic interchange format (GIF) image encryption method based on compressed encoding
  • Graphic interchange format (GIF) image encryption method based on compressed encoding
  • Graphic interchange format (GIF) image encryption method based on compressed encoding

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0072] Embodiment one: if figure 1 Shown, a kind of GIF image encryption method based on compression coding is characterized in that comprising the following steps:

[0073] Step 1. Input the GIF plaintext image;

[0074] Step 2, the color list of GIF image is encrypted; The described color list of GIF image is encrypted according to the following steps:

[0075] Set the key stream as K={K n ∣0n <1}, n is a positive integer, and the key stream is obtained by iterative piecewise linear chaotic map, which is prior art and can be accurately understood by those of ordinary skill in the art, so it will not be explained too much here; set the GIF image Each color component in the color list of is T(x,y), T(x,y)∈[0,255], x, y are integers and x∈[0,255], y∈[0,2];

[0076] The value K in the keystream n Multiply by 255 and round to get K n '; Set the color list of the encrypted GIF image as T'(x,y); calculate Get the color list of the encrypted GIF image;

[0077] The key strea...

Embodiment 2

[0084] Embodiment two: if figure 2 Shown, a kind of GIF image encryption method based on compression coding comprises the following steps:

[0085] Step 1. Input the GIF plaintext image.

[0086] Step 2, carry out LZW encoding encryption to the image data of GIF image: described carry out LZW encoding encryption to the image data of GIF image and carry out as follows:

[0087] S1. Initialize the dictionary and scramble the dictionary; wherein the scrambling of the dictionary is performed according to the following steps:

[0088] A1, initialize the dictionary so that the dictionary contains all single characters;

[0089] A2. Set the index of the element currently to be scrambled as i, and initialize the value of i to the number len of elements contained in the current dictionary;

[0090] A3. Calculate r is a random number; exchange the elements of i and r in the dictionary;

[0091] A4. Calculate i'=i-1; when i'≥2, return to step A2, otherwise end scrambling.

[0092...

Embodiment 3

[0119] Embodiment three: as image 3 Shown, a kind of GIF image encryption method based on compression coding comprises the following steps:

[0120] Step 1. Input the GIF plaintext image;

[0121] Step 2, encrypt the color list of the GIF image and carry out LZW encoding encryption to the image data of the GIF image:

[0122] The described color list of the GIF image is encrypted according to the following steps:

[0123] Set the key stream as K={K n ∣0n <1}, n is a positive integer; the key stream is obtained by iteration of the piecewise linear chaotic map, and each color component in the color list of the GIF image is set as T(x, y), T(x, y)∈[ 0,255], x, y are integers and x∈[0,255], y∈[0,2];

[0124] The value K in the keystream n Multiply by 255 and round to get K n '; Set the color list of the encrypted GIF image as T'(x,y); calculate Get the color list of the encrypted GIF image;

[0125] The image data of the GIF image is carried out to LZW encoding and encry...

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Abstract

The invention discloses a graphic interchange format (GIF) image encryption method based on a compressed encoding and belongs to the field of digital image encryption. According to an algorithm, encryption is performed by selecting color lists of the GIF image and lempel-ziv-welch (LZW) compressed encoding data. When the color lists are encrypted, a key stream is utilized to mix up values of color components in the color lists, and thereby information of plaintext image color indexes can be hidden; when the LZW encoding data is encrypted, a dictionary used by encoding is subjected to scrambling when dictionary entries are matched according to the features of the LZW compression, so that the scrambling algorithm can self-adaptively and dynamically adjust the encryption intensity according to plaintext features, and the encryption efficiency and the safety are good. According to the GIF image encryption method based on compressed encoding, the GIF compressed encoding design encryption algorithm is combined, simultaneously the safety of the GIF image color indexes and the image compressed data is considered, the GIF image color indexes and the image compressed data are respectively encrypted, and good safety is achieved. After the encryption operation is introduced, the GIF image compressed effect is not affected, and the format compatibility of original GIF images is maintained.

Description

technical field [0001] The invention belongs to the field of digital image encryption, in particular to a GIF image encryption method. Background technique [0002] With the rapid development and popularization of information technology and network communication, more and more images and other multimedia information need to be stored and transmitted on the network. These multimedia information may be obtained and used by some attackers with ulterior motives, which will bring various losses and harms. Therefore, information security technology has been paid more and more attention by people. Encryption technology is an important means to ensure information security. However, traditional encryption methods such as DES and AES have some inherent weaknesses, such as low encryption speed and no consideration of redundant information in the multimedia information to be encrypted. Using them Encrypting multimedia information still has many unsatisfactory places. Therefore, many r...

Claims

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Application Information

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IPC IPC(8): H04N7/26H04N11/04H04N19/46H04N19/88
Inventor 向涛王安肖迪周庆杨吉云
Owner 重庆艾博特科技有限公司
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