how to encrypt data incoming in chunks?

[David]

I need to encrypt a large data (e.g. file) that is incoming in chunks.
Ideally, I would like to have a source that I can feed with more
chunks as they arrive, and ask the transformation to "chew" more data.
If the chunks are not aligned with the block size, I'd like to
transformation to deal with it, i.e. keep state between calls.

I'd like my component to expose to its clients an interface of the
sort:

encrypt(buf, size)
getChunk(buf, size)
finalize()

any suggestions how to do it with cryptopp? any examples available?

thanks
David

[David]

Sorry, "getChunk" could be confusing, should be "addChunk" or
something...