First of all an important technical detail. You say that you want to encrypt and then compress. Unfortunately in order to compress you need to find and take advantage of patterns in the data - and encryption tries to make sure there are no understandable patterns. Therefore you need to compress and then encrypt.

For a compression library I would use Compress::ZLib. If you want to stream you will need to use deflateInit/deflate/flush for compression and inflateInit/inflate for decompression. (Read the documentation for details - I don't have time at the moment to hack up some pseudocode.)

One warning. You need to think through what your buffering strategy is. Compression and encryption work best when they get as much data as they want to do a chunk of work. Streaming data often cares about latency. The two goals conflict - if a message halfway fills a compression buffer and you let compression work like it wants to, the message won't get sent for an indefinite amount of time.

Two articles that may help you understand the warning. See Suffering From Buffering and then It's the Latency, Stupid. If you read those and don't follow my point, just ask.

UPDATE
A random tip which is not quite worth a new post. If you are on Windows, you will need to look at binmode.

In reply to Re (tilly) 1: Streaming Compression by tilly
in thread Streaming Compression by satanklawz

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