本标准描述了C4 Base58字符集、单个连续数据单元（如文件）的C4 ID格式和构造，以及非连续数据单元（如流中的文件或块集合）的C4 ID构造方法。

This standard describes the C4 Base58 character set, the format and construction of the C4 ID for a single contiguous unit of data (e.g. a file) and method of construction of a C4 ID for non-contiguous units of data (e.g. collection of files or blocks in a stream).