png-parser - 分析CTF、Python API和CL的PNG文件格式

项目说明

png-parser

Best tool to analyse PNG files, it shows you PNG chunks : header, palette, and text.

!demo

!demo text

Usage

API

Class PngParser

PngParser(file)

file: str or file type

PngParser.get_image_data()

PngParser.set_image_data()

PngParser.get_chunk_by_index(idx)

PngParser.get_chunk_by_type(type)

Class Chunk

Chunk(type, data=None, crc=None)

Chunk.update_crc()

Chunk.length

Class ImageData

ImageData(header, data, palette=None)

ImageData.scanlines

ImageData.get_pixel(x, y)

ImageData.set_pixel(x, y, pixel)
ImageData.set_pixel(x, y, data)

Class Scanline

Scanline(filter, data, previous=None)

Scanline.filter

Scanline.data

Class Pixel

Pixel(type, channels)
Pixel.__getitem__

Dev

Install for de

Run example

DOC

PNG Chunks

| Length | Chunk type | Chunk data | CRC |
|---------|------------|--------------|---------|
| 4 bytes | 4 bytes | Length bytes | 4 bytes |

Critical Chunks:

IHDR : must be the first chunk; it contains (in this order) the image's width,

height, bit depth, color type, compression method, filter method, and
interlace method (13 data bytes total).

PLTE : contains the palette; list of colors.

IDAT : contains the image, which may be split among multiple IDAT chunks.

Such splitting increases filesize slightly, but makes it possible to
generate a PNG in a streaming manner. The IDAT chunk contains the
actual image data, which is the output stream of the compression
algorithm.

IEND : marks the image end.

Ancillary Chunks:

bKGD : gives the default background color. It is intended for use when there

is no better choice a, such as in standalone image (but
not web browsers; see below for more details).

cHRM : gives the chromaticity coordinates of the display primaries and white

point.

dSIG : is for storing digital signatures.

eXIf : stores Exif data.

gAMA : specifies gamma.

hIST : can store the histogram, or total amount of each color in the image.

iCCP : is an ICC color profile.

iTXt : contains a keyword and UTF-8 text, with encodings for possible

compression and translations marked with language tag. The Extensible
Metadata Platform (XMP) uses this chunk with a keyword
'XML:com.adobe.xmp'

pHYs : holds the intended pixel size and/or aspect ratio of the image.

sBIT : (significant bits) indicates the color-accuracy of the source data.

sPLT : suggests a palette to use if the full range of colors is una.

sRGB : indicates that the standard sRGB color space is used.

sTER : stereo-image indicator chunk for stereoscopic images.[15]

tEXt : can store text that can be represented in ISO/IEC 8859-1, with one

key-value pair for each chunk. The "key" must be between 1 and 79
characters long. Separator is a null character. The "value" can be any
length, including zero up to the maximum permissible chunk size minus
the length of the keyword and separator. Neither "key" nor "value" can
contain null character. Leading or trailing spaces are also disallowed.

tIME : stores the time that the image was last changed.

tRNS : contains transparency information. For indexed images, it stores alpha

channel for one or more palette entries. For truecolor and
grayscale images, it stores a single pixel value that is to be regarded
as fully transparent.

zTXt : contains compressed text (and a compression method marker) with the

same limits as tEXt.

(c)

项目信息

开发语言：Python

Star 数：103

技术要点

该项目属于CTF思路方向的开源资源，代码结构清晰，适合安全研究人员学习参考。项目围绕Analyse PNG file format for CTF, python API and CLI展开，提供了可运行的实现，对理解相关安全机制、工具原理与攻防技术具有较高的研究价值。

从技术实现角度看，此类项目的核心在于对底层原理的深入理解与工程化落地。开发者在研究过程中可以结合官方文档与社区讨论，梳理项目的初始化流程、核心模块职责与数据流转，逐步掌握其中的技术细节与设计思路。

使用与学习建议

1. 下载源码压缩包，解压到本地环境。

2. 根据项目类型准备对应的运行环境与依赖。

3. 按照 README 中的步骤完成配置与部署。

4. 在隔离的测试环境中运行验证，避免影响生产系统。

免责声明

本资源来源于开源社区，仅供安全研究、技术学习与合法授权范围内的攻防演练使用，请勿用于任何非法或侵害他人权益的用途。使用本项目产生的一切后果由使用者自行承担。