roman_mir, It would have been clearer if you referred to it as base 64 *encoding*, rathern than encryption, since it has nothing to do with cryptography.
On an unrealted note, with regards to the V8 performance test, the reason Chrome's V8 engine works well with the V8 benchmark is because the tests themselves are bias towards the specific optimisations that the Chrome developers have chosen to include in their V8 engine.
Carakan, on the the other hand, has, for various reasons, been developed to optimise for different cases. There are trade-offs here which, as a result, affect the performance of Carakan in some of the tests included in the V8 performance test.
Disclaimer: I work for Opera the on Carakan team. I cannot go into specifics about what optimisations and trade-offs have been made.