A secure, lossless, and compressed Base62 encoding
Kejing He, Xiancheng Xu, Qiang Yue · 2008
In many applications and protocols, the number of usable characters is limited. Base64 or other similar algorithms are widely used to encode the binary data into a printable representation. But base64 itself can¿t compress data, contrarily, it inflates the binary data by 33%. This paper presents a lossless base 62 compressed encoding method that only use alphanumeric characters to represent the original data. Burrows-Wheeler Transform (BWT) is used along with range coding to compress data before it is transfered to base 62 encoder. And a simple encryption mechanism is incorporated to provide basic security. This base62 compressed encoding has been tested using the Canterbury corpus, and this paper also presents a comparative study with other similar methods. It can be used for compressing data into base 62 format in wide-range applications, e.g., URL encoding, Internet Mail Transfer, and embedding binary objects into XML files.