Abstract: A method and system for streaming dynamically generated Zip archive file content using a standard, non-streaming Zip archive format. In response to a request from a client to receive one or more files, a Zip archive file is dynamically generated that includes at least one file that is altered while servicing the request, wherein the size of the altered file is unknown prior to completion of the alteration operation. For a Zip file entry corresponding to an altered file, a local file header including an overestimated file size and predetermined CRC32 value is generated. After alteration, the file entry content is adjusted using padding and a CRC32 adjustment such that the length and CRC32 values for the resulting Zip file entry match the overestimated file size and predetermined CRC32 value. Examples of file alteration operations include watermarking, compressing, and/or encrypting the file content.