I'm playing around with a package that does Elliptic Curve Cryptography from <http://jecc.sourceforge.net/>

Every time I encrypt a value it produced a different result (same private key). However I'm always able to decrypt this result with the related public key. For a 1 byte result the resulting data is 34 bytes, 2 bytes the resulting data is 35 bytes. I assume some knowledge of the curve is contained in the result. 

Is this a feature of ECC or would you assume it is just this implementation?