Question : how to random access or skip during decryption

### Problem:

I have a need to handle large files and service a random address range for decryption.
Looking throgh the exampes I dont see an effecient way to do this.
It seems that the underlying encryption data is framed, but the CryptoInputStream doesn't skip in an input stream, and there isnt a support for a Readable Channel that I am aware of

### Solution:
With the existing API - I could use skip in the InputStream, but this will (as I see it) decrypt and throw away the skipped bytes, with extra I/O and CPU load
With an enhanced implementation we could skip on the input stream to the start of a frame and then decrypt that frame (skipping internally to the offset needed by decodng and thowin a few bytes if needed)

### Out of scope:

Comienza con la API existente de CryptoInputStream y su comportamiento de entrada de datos cifrados enmarcados; después, compara InputStream.skip con la compatibilidad solicitada para Readable Channel. Se considerará completado cuando un llamador pueda atender un rango de direcciones aleatorio buscando el frame relevante y evitando el descifrado y la I/O de los bytes descartados.

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