False alarm. I was basing this on an older description of Nxt. The code already removes effects of age on hashing power. Going to delete older posts.
Specifically, I was confused by this:
Alice has 2500 nxts on her account. Last time she found a block 4 days ago. Her money is like a mining rig with hashpower equal to 2500 * 4 = 10000 GH/s.
Bob has 1000 ntx on his account. He was on vacation and hasn't opened his account for 20 days. His money is like a mining rig with 1000 * 20 = 20000 GH/s hashpower.
Bob has 1000 ntx on his account. He was on vacation and hasn't opened his account for 20 days. His money is like a mining rig with 1000 * 20 = 20000 GH/s hashpower.
But later BCNext says this (see below), which doesn't mention coin-age at all. So like you say he must have changed the spec. I was confused why he criticized PPCoin and ended up adopting an almost identical system. It would make a lot more sense if he dropped coin age altogether.
It's a good chance to tell the details...
Each block has "generationSignature" parameter. An active account signs "generationSignature" of the previous block with its private key. This gives 64 bytes which are hashed with SHA256. The first 8 bytes of the hash gives a number (I call it a "hit"). The hit is compared to the current "target" (64bit number). If the hit is lower than the target then next block can be generated.
The target for each account is proportional to the balance. Someone holding 1000 coins gets a 50 times bigger target than someone with 20 coins. Thus the owner of 1000 coins will generate 50 times more blocks than the owner of 20 coins (in the long run).
The target is not constant, it grows each second passed since the timestamp of the previous block. If noone generated a block on the first second then the target becomes 2 times bigger and so on. The base target is the target on the 60 second mark. If there is only a few active accounts then after a long time someone will generate a block because the target will become very big. If you open the client and log with any funded account you can see a ticking timer in BLOCKS widget. It shows when the target will become greater than your hit.
Each block has "generationSignature" parameter. An active account signs "generationSignature" of the previous block with its private key. This gives 64 bytes which are hashed with SHA256. The first 8 bytes of the hash gives a number (I call it a "hit"). The hit is compared to the current "target" (64bit number). If the hit is lower than the target then next block can be generated.
The target for each account is proportional to the balance. Someone holding 1000 coins gets a 50 times bigger target than someone with 20 coins. Thus the owner of 1000 coins will generate 50 times more blocks than the owner of 20 coins (in the long run).
The target is not constant, it grows each second passed since the timestamp of the previous block. If noone generated a block on the first second then the target becomes 2 times bigger and so on. The base target is the target on the 60 second mark. If there is only a few active accounts then after a long time someone will generate a block because the target will become very big. If you open the client and log with any funded account you can see a ticking timer in BLOCKS widget. It shows when the target will become greater than your hit.
tia! 
