user12645: Let me introduce my idea.
Given:

sizeof( Blockchain ) = 16Gb
Downloading of one avi film 16GB from the pirate bay ( 5mb/s ) = 2-3 hours
Downloading of bitcoin's blockchain ( 5mb/s ) = 2-3 days
One day = 6 * 24 = 144 blocks.
Drag - cryptography. 

Task:

Accelerate boot of fresh client to the torrent speed. Similar to Bootstrap.


As I can see, downloading of blockchain is the same hard as mining, because there is every time recalculation of hash, comparing, checking of signs, etc...
What if client will only download this 144 blocks for a day and one super block with 144 hashs of the last valid blocks, thereafter only compare current wallet's addresses with addresses in this 144 blocks without any calculation of its hash.
Is there any alt-coin with such accelerator? 

E.g. this super blocks might be archived into another ultra-block for a month. Than we have similar to sha(sha(text)) cascade shield against bruteforce attack. 

Downloading of blockchain should takes at max the same time as downloading of 16GB avi from the pirate bay. Say, 5mb/s internet channel + p2p / 16 Gb = 2, may be 3 hours ( in the no peers case ), but I spent 2 - 3 days, and I see that this is no internet speed reason, it is CPU + harddisk very very hard job.

user575: Your premise is wrong. The work required to download and validate the blockchain has nothing at all to do with the work required to mine it.
As far as the block hash goes, validating it requires just one hash while mining the block requires quintillions of hash calculations.
Validating the block also requires computing the hashes of the Merkle tree but the main work is validating ECDSA signatures. Your method is not going to help with that.
(On a meta note, it's rude to offer "improvements" when you don't understand well enough what currently exists.)

user4748: Downloading the blockchain is several orders of magnitude easier than mining. Validating is just taking the blocks, hashing them and verifying that the proposed solution a) matches such hash and b) at the specified difficulty level. If a received block passes these validations, it's accepted as valid an the next one is requested, and so on.
Per comparison, downloading a movie or software implies no validation until the very end, when you check the archive is not corrupted. In case it indeed is, you have to download the whole big mess again .
As you correctly assume, most of the time is spent in verifying blocks. That's why even if a friend lends you a DVD with the blockchain, loading it for the 1st time won't be instantaneous but will take (depending on your PC's speed) from half an hour to several hours.
Your idea of creating a "resume" block at the end of the day (why not weekly/monthly/annually as well?) looks promising, I've heard of no coin implementing any such idea. It's not without potential problems, but it could be.

12645: <p>Let me introduce my idea.</p>

<p>Given:</p>

<ul>
<li>sizeof( Blockchain ) = 16Gb</li>
<li>Downloading of one avi film 16GB from the pirate bay ( 5mb/s ) = 2-3 hours</li>
<li>Downloading of bitcoin's blockchain ( 5mb/s ) = 2-3 days</li>
<li>One day = 6 * 24 = 144 blocks.</li>
<li>Drag - cryptography. </li>
</ul>

<p>Task:</p>

<ul>
<li>Accelerate boot of fresh client to the torrent speed. Similar to <strong>Bootstrap</strong>.</li>
</ul>

<hr>

<p>As I can see, downloading of blockchain is the same hard as mining, because there is every time recalculation of hash, comparing, checking of signs, etc...</p>

<p>What if client will only download this 144 blocks for a day and one super block with 144 hashs of the last valid blocks, thereafter only compare current wallet's addresses with addresses in this 144 blocks without any calculation of its hash.</p>

<p>Is there any alt-coin with such accelerator? </p>

<p><hr>
E.g. this super blocks might be archived into another ultra-block for a month. Than we have similar to sha(sha(text)) cascade shield against bruteforce attack. </p>

<p>Downloading of blockchain should takes at max the same time as downloading of 16GB avi from the pirate bay. Say, 5mb/s internet channel + p2p / 16 Gb = 2, may be 3 hours ( in the <code>no peers case</code> ), but I spent 2 - 3 days, and I see that this is no internet speed reason, it is CPU + harddisk very very hard job.</p>
 575: <p>Your premise is wrong. The work required to download and validate the blockchain has nothing at all to do with the work required to mine it.</p>

<p>As far as the block hash goes, validating it requires just one hash while mining the block requires quintillions of hash calculations.</p>

<p>Validating the block also requires computing the hashes of the Merkle tree but the main work is validating ECDSA signatures. Your method is not going to help with that.</p>

<p>(On a meta note, it's rude to offer "improvements" when you don't understand well enough what currently exists.)</p>
 4748: <p>Downloading the blockchain is several orders of magnitude <em>easier</em> than mining. Validating is just taking the blocks, hashing them and verifying that the proposed solution a) matches such hash and b) at the specified difficulty level. If a received block passes these validations, it's accepted as valid an the next one is requested, and so on.</p>

<p>Per comparison, downloading a movie or software implies no validation until the very end, when you check the archive is not corrupted. In case it indeed is, you have to download the whole big mess again .</p>

<p>As you correctly assume, most of the time is spent in verifying blocks. That's why even if a friend lends you a DVD with the blockchain, loading it for the 1st time won't be instantaneous but will take (depending on your PC's speed) from half an hour to several hours.</p>

<p>Your idea of creating a "resume" block at the end of the day (why not weekly/monthly/annually as well?) looks promising, I've heard of no coin implementing any such idea. It's not without potential problems, but it could be.</p>
