Yes, one could try splitting coins into different transactions but there is no guarantee that you would consume the coin days of each of those groups consecutively. Coin days are only consumed when a stake is generated, right? The attacker cannot use up his accumulated coin days in those different transactions at his desired time.

It would take a very very long time for him to be lucky enough. It may take years and years because every time he fails, he would have to wait another 30-90 days to try it again. We seriously need a mathetician to show just how the odds are against the attacker.

It would be interesting to know how many years would it take for a person with 50% of all PPC to generate 6 blocks in a row. In bitcoin, the probability is 1.5625% and the time to wait for another try is 10 minutes. So to have a somewhat guaranteed 6 blocks in a row, it would take ([100/1.5625]x 10 minutes) = 640 minutes.

In peercoin, the probability is lesser than 1.5625% (since chances of solving a consecutive block decreases when a block is solved) and the time to wait for another try is 30-90 days. So for example, the scenario is that the attacker has 50% of all minting power of the PPC network. The goal is to find 6 blocks consectively. He then splits his coins into 6 groups so that each split will have 8.333% of all PPC. He lets them age for 90 days to ensure maximum success. Assuming all of the PPC in the network are minting at maximum age (90 days), how long would it take to have a guaranteed success of 6 blocks in a row?

Probability of finding the 1st block:

50%

Finding 2 blocks in a row:

[(50-8.333)/(100-8.333)] x 0.50 = 22.72%

Finding 3 blocks in a row:

[(50-8.333 x 2)/(100-8.333 x 2)] x 0.2272 = 9.088%

Finding 4 blocks in a row:

[(50-8.333 x 3)/(100-8.333 x 3)] x 0.09088 = 3.029%

Finding 5 blocks in a row:

[(50-8.333 x 4)/(100-8.333 x 4)] x 0.03029 = 0.757%

Finding 6 blocks in a row:

[(8.333)/(100-8.333 x 5)] x 0.757 = 0.108%

Comparing this same scenario in bitcoin but in hashing power,

Probability of finding the 1st block:

50%

Finding 2 blocks in a row:

0.5 x 0.5 = 25%

Finding 3 blocks in a row:

0.25 x 0.5 = 12.5%

Finding 4 blocks in a row:

0.125 x 0.5 = 6.25%

Finding 5 blocks in a row:

0.0625 x 0.50 = 3.125%

Finding 6 blocks in a row:

0.03125 x 0.50 = 1.5625%

Just looking at this, a 50% attack in PPC has a success chance of 0.108% while in BTC it is 1.5625%. That doesn’t even take into consideration the time-to-wait for another trial. And so…

To have a somewhat guaranteed (~100%) 6 blocks in a row in Bitcoin, it would take ([100/1.5625]x 10 minutes) = 640 minutes.

To have a somewhat guaranteed (~100%) 6 blocks in a row in Peercoin, assuming the attacker let’s his coins age for 90 days for maximum success, it would take ([100/0.108]x 90 days) = 83,333 days or 228 years.

Personal disclosure: I’m no mathematecian so don’t take these words so easily but I hope it makes sense and you all get my point.

Conclusion:

PPC is damn secure.