Which of the following is a lossless compression algorithm?

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Lossless compression algorithms are used to reduce the size of files without losing any data. This means that when the compressed file is decompressed, it will be identical to the original file. In this article, we will explore different compression algorithms and determine which one is a lossless compression algorithm.

Lossless Compression Algorithms

There are several lossless compression algorithms available, but one of the most commonly used is the ZIP algorithm. ZIP compression is widely supported and can be found in various operating systems and software applications. It uses a combination of different techniques to reduce file size without losing any data.

ZIP compression works by identifying repeated patterns in the data and replacing them with shorter representations. It also uses a technique called dictionary encoding, where frequently occurring patterns are stored in a dictionary and referred to by shorter codes. This allows for efficient compression and decompression of files.

Another lossless compression algorithm is the GZIP algorithm. GZIP is often used to compress web pages and other text-based files. It is based on the DEFLATE algorithm, which combines LZ77 compression and Huffman coding. LZ77 compression replaces repeated patterns with references to previous occurrences, while Huffman coding assigns shorter codes to more frequently occurring patterns.

The PNG (Portable Network Graphics) file format also uses lossless compression. PNG compression is based on a combination of different techniques, including DEFLATE compression and adaptive filtering. It is commonly used for images that require lossless compression, such as logos and graphics.

Comparison and Selection

When comparing lossless compression algorithms, it is important to consider factors such as compression ratio, speed, and compatibility. The compression ratio refers to the amount of compression achieved compared to the original file size. A higher compression ratio means a smaller compressed file size.

In terms of compression ratio, ZIP and GZIP algorithms are known to achieve good results. They can significantly reduce file sizes without losing any data. PNG compression also performs well for images, especially those with large areas of uniform color.

When it comes to speed, ZIP compression is generally faster compared to GZIP compression. This is because ZIP compression does not require the extensive dictionary lookups that GZIP compression does. PNG compression can be slower, especially for larger images, due to the adaptive filtering process.

In terms of compatibility, ZIP compression is widely supported and can be opened on various operating systems. GZIP compression is commonly used for web-related tasks and is supported by most web browsers. PNG compression is supported by most image editing software and web browsers.


In conclusion, all of the following compression algorithms are lossless: ZIP, GZIP, and PNG. These algorithms are widely used and offer efficient compression without losing any data. When selecting a compression algorithm, it is important to consider factors such as compression ratio, speed, and compatibility based on the specific requirements of the files being compressed.


– zip.org
– gzip.org
– png.org