Quote from: smooth on May 07, 2015, 08:07:19 PM

Quote from: dlightman on May 07, 2015, 07:57:38 PM

In case a node doesn't verifies signatures we don't have to consider it as a full node i.e. we can't rely on such node's decisions because they will accept correct PoW with wrong signature. We have to consider such nodes as light wallets.

Exactly yes, that's why I called them a "lightweight client model"

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Network with majority of nodes not verifying signatures can be easily manipulated by big pools.

Full nodes will still verify signatures.

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Let's calculate scratchpad reduction benefit for a low-end device in case of current block verification:

- 120 seconds block target time
- 10 h/s hash calculation speed

In this case one block verification takes 0.083333% of one CPU core time. Is this a showstopper for mobile device?

It could be. If you are two days behind when you open your wallet, that is 144 seconds to sync. Quite a long wait.

Also, I'm not sure that 10 h/s is achievable on a mobile device with scratchpad in RAM. Maybe, but that is aggressive. It is more realistic if scratchpad is in cache.

Scratchpad in RAM is about 8-10 times slower than scratchpad in cache. Speed on embedded CPU depends also on x64 mul/div and aes-ni. Emulation of both will be really slow. Do you plan to remove these instructions also? Wink

In case of low-end device and light-client being two days behind it's probably more user friendly to start from transactions (check if there is some incoming coins). In case there are some incoming transactions you can display amounts as not verified yet and check PoW in the background. This way user will wait several second for downloading and transactions verification.