Stealing anything is illegal.. 
But is it punishable by law? Then its a big NO for you.
Illegal is unlawful. For something to be illegal it has to be specified in written law. Most countries don't have a policy on bitcoin, so stealing it isn't illegal. But is it punishable by law? Then its a big NO for you.Well, that statement just sucked 50 IQ points off everyone.
Most countries don't have a policy on tiddlywinks, either. However, stealing a kid's tiddlywinks is still theft. Punishable by law. As is stealing Bitcoins. Whether or not specifically addressed by proper name in the text of the law.