AES-256 CBC decrypt is incredibly slow and CPU-intensive with large bytes of data

[loves-bruins]

Hello,
We are using CryptoSwift at our company and it has worked well with decrypting (AES-256 CBC) small chunks of data. However I download a required file for an update. That file has been encrypted using AES-256 CBC and is about 23 megabytes in size. CryptoSwift decrypt does work but it pegs CPU and takes about 1 full minute to decrypt when on a high priority thread.
Any ideas on why it's taking so long? My guess it should be seconds to decrypt.
/Loren

[krzyzanowskim]

if this is a debug build, then it's the nature of the Swift debug builds. Release (optimized) build should be > 1000 times faster. So the first thing is this.

[loves-bruins]

It is indeed a debug build! That is excellent news. Thank you