[Scope:]

Scope:
Introductory level (presumably collage courses, although I would gladly do high-school homework as well) courses in calculus, classical mechanics, electricity and magnetism, and thermodynamics.
I can do more advanced work (relativity, quantum mechanics, Lagrangian/Hamiltonian mechanics), but I don't feel like it, so expect to pay more for it. Also, more advanced students tend to understand that outsourcing their homework defeats its purpose.
Volume:
Probably not more than one problem set a week (I have my own homework to do), sometimes none if I am too busy.
I will keep the status on this post.
Directions:
Send me via my PM box or arccsch@gmail.com (send me a short PM as a notification if you use email for the data, as I rarely check that email address) the following contents (can be google docs/drive links):
-Your user-name.
-The problems assigned.
-The relevant pages of the textbook, if problems are assigned from one.
-Pages containing any definitions, diagrams, and formulas referenced in the problems.
-The due date, include time zone.
-The amount offered as payment.
-The address(es) the payment is on.
Please apply as early as possible, preferably on the same day as the homework is posted, confirmation must be at least 50 hours before due time.
I will reply as soon as possible, negotiate the price, if I accept your offer, I will ask you to confirm it.
To confirm it, you must send me at least 25% of the agreed bitcoin value up front (will be refunded if I must cancel the deal, but not if you do) I will then start to work on it.
After I finish it, I will inform you and request payment (minus the 25% paid at confirmation), after you pay, I will send you the completed assignment .tex file (you can use www.sharelatex.com to generate .pdf flie).
Terms of service:
If outsourcing your homework is not allowed for your class, please do not use this service.
I do not guarantee that the homework will contain no mistakes, please check the homework before submitting it, it only takes a couple of minutes.
Remember that the purpose of homework is to further your learning, do not be surprised if you flunk the final exam after outsourcing your homework.
Payment:
I only accept payment in bitcoin.
To estimate a reasonable fee, multiply the estimated time to do the homework (can usually be derived from the syllabus or the first lecture) by a decent wage (somewhat above minimum wage), for example, if the professor says "5 hours per week" and there are three 50 minute classes per week, that leaves 2.5 hours for homework, so at a high rate of $18/hr, this comes to 50mBTC, at a lower rate of $9/hr, this comes to 25mBTC, this is the approximate range of rates.
Questions and answers:
Are you doing this yourself, or are you part of a group?
I am doing this alone.
Why must I send you a private message even if I send an email?
I rarely check that address, I may not see it if you don't send me a private message informing me of the email.
Status:
TEMPORARILY CLOSED

There is a thread about recomendations for the best wallet to use, but not all practice what they preach, so this poll is to see what people are actually using.
I understand that some people use multiple wallets of different kinds, so this poll asks which wallet is most used, this can be measured either by quantity of bitcoin or ammount of transactions.

[(1)Download the generator from https://bitcoinpaperwallet.com/, open it and skip randomness generation:]

(1)
Download the generator from https://bitcoinpaperwallet.com/, open it and skip randomness generation:



(2)
Use a strong passphrase, enter it into the "brain-wallet" box, ad a backslash, and add a salt (something you can easily remember but is quite unique, to prevent hackers from going after everyone at once, such as your name or phone number) type the same thing into the BIP38 encryption:



(3)
Copy the encrypted private key (6PRUVtdGSuoypYyf2hAWukGzZVrtE2b89QrXXyVXuVHRQgWA8oj4N9fumC) to the "brain-wallet" box, turn off BIP38, and create the wallet:




(4)
Use this as your brain wallet, it is more secure than a regular brain wallet because BIP38 key-stretching prevents hackers from searching quickly, and the salting in step 3 prevents hackers from attacking everyone at once.
Note that this is a way to improvise on existing software to create a secure brain wallet, a better solution would be software that automatically uses scrypt stretching for brain wallets, but this is not currently available.
EDIT: Use Warp Wallet.
Also, don't use any suggestion (specially one from a n00b like myself) for large amounts of Bitcoin until it has been adequately peer-reviewed.

The scheme:
Let multiple users create a private-public key pair, submit the public keys, and request a vanity pattern.
Let the vanity miners create key-pairs, combine the public key with all the submitted public keys, and check address against all patterns.
When a pattern is found for a user, all other users submit their private keys, the lucky user can combine them with his/her own to create a full private key, and the rest create a new pair.
Advantage:
Vanity miners can mine for multiple users simultaneously, cutting the computational cost.
Disadvantage:
Troublemakers can refuse to reveal keys, causing the whole computation to go to waste.
Discussion:
Has this been suggested before?
Is this practical?
Is this secure?

CPU coins (their proponents actually) claim greater decentralization and low barriers to entry.
I presume that disadvantages of CPU coins fall into two categories:
(1) Not a good idea in the first place.
(2) Someone can always make an ASIC.

Memory-hard proponents claim more difficulty in building an ASIC.
I presume that disadvantages of memory-hard coins fall into two categories:
(1) Hard to verify.
(2) Scrypt ASICs exist.

Some people claim that Hashcash is good enough, they claim that ASICs are reaching the limits of performance, and it would soon be practical for hobbyists and people in general to buy a relatively cheap USB and mine on a small scale, without it going obsolete in months. Others cite the growth of giant mining farms and are afraid of China dominating bitcoin.

What are the pros and cons of different mining schemes?
I am only comparing different types of PoW, not PoW vs. PoS vs. PoD vs. PoB vs etcetera...

9f9119fbda62be97d1c6438a23959b450a5573e0ecb4062c3704f740769e537c
This is still unconfirmed, but some outputs are spent, how is this possible?
Don't you need the output to be confirmed first?
I have a screenshot, but don't know how to include an image.

EDIT:
Thanks, californiaquail!
http://imgur.com/a/7Yxph

I recently funded a paper wallet with coin I got from a faucet, here is the id:
b606ad986d7c16e0a8b13d6a5a5a58bbb938413b04c74bfcc32b711478ad43e1
I got it confirmed by 1Hash after 144min despite including a fee of only 0.01mBTC.

I am considering to buy bitcoin in tangible am mounts, (more than the couple of mBTC I made at a faucet) andneed a way to store them, I have access to 3 computers (and 1 printer) and my scheme goes as follows:

Generate 3 independent long strings (50 rolls each) key strings using dice.

On each computer, go offline, generate a key-pair (prferably use different software for each), encrypt the private key with one of the strings, go online, and print the result.

Combine the addresses into a 3/3 multi-signature address.

Place the 3 private keys, with their respective key strings, in an envelope.

To receive coins, have them sent to the multi-signature address.

To spend coins, decrypt one key (offline, preferably on the same computer that generated it), sign the transaction, delete the decrypted key, send it to the second computer, go offline, decrypt the key, sign it, delete the decrypted key, repeat this for the third computer, and broadcast the transaction.


Is this a good way to store coins?
I am not clear on some details, how do I preform this procedure?
Is it a good idea to test the set-up with pocket change and reuse the same keys for large amounts?

[Idea #X]

This thread is for anyone (newbies included) with new ideas for altcoins, the ideas need not be complete.
If you have a new idea, post Idea #X followed by your idea (edit post to add to it later), otherwise(if you are commenting on an existing idea), just post #X above your comment.
EDIT#1:
The ideas must be related to the development of new altcoins, not how to use them!
EDIT#2:
The purpose of this thread is to provide a repository of ideas to developers aiming to create new altcoins, please do not spam it with frivolous drivel.

According to Bitcoin Wiki:
"Block chain length" is calculated from the combined difficulty of all the blocks, not just the number of blocks in the chain. The one that represents the most computation will win.

The worry addressed there was that an attacker reduces block difficulty, creating lots of new blocks.

There is, however, another concern, an attacker may increase block difficulty to just above that of the whole competing block chain.
Since PoW is added linearly to the 'true' chain, the attacker's probability rate of success is inversely proportional to the time.
Since the integral of 1/x diverges at infinity, any attacker, even with an arbitrarily small fraction of the total hash rate, will almost certainly eventually overtake the network.

Is this a problem?
Can this be prevented?
Are there any safeguards to prevent this?

As pointed out in this post, new altcoin ideas pop up very often, often posted by newbies like myself.
I think it would be helpful to create a new forum for such topics.
It would benefit developers by providing a large pool of diverse ideas they can build on, and benefit everyone else by freeing up the Altcoin Discussion.

The title explains it all, you look at blockchain.info and see a burst of transactions sending a total of 1000000BTC to 1BitcoinEaterAddressDontSendf59kuE.
What happens next?
Would it make headlines?
Would the exchange rate rise significantly?
Is it likely?

This cryptocurrency combines features from Bitcoin and my previous invention, Dust.
Each lump attempt (iterated by miners) has the following form:

MinerAddress Difficulty BlobFee PreviousBlockHash Counters HashRoot Iterator

MinerAddress - Self explanatory.
Difficulty - Set by network (I don't know exactly how this works).
PreviousBlockHash - Self explanatory.
Counters - Blockhight and LumpNumber.
HashRoot - Hash of recent transactions and blobs.
Iterator - Self explanatory.

For the lump to be valid, the first bits of the hash H(MinerAddress Difficulty PreviousBlockHash HashRoot Iterator) must pass the Difficulty.
The last four bits of the hash determine whether the the lump is a block (if they are 0000) or a blob otherwise.

Blobs are added to the block chain, (with the HashRoot included simply as a string of bits) and do not conflict with each-other, multiple blobs can sit side-by-side in the block chain, each of them confirming the previous block.
Blocks are added to the block chain, they confirm (and contain) the recent transactions (transactions are no different from bitcoin transactions) and recent blobs.


If the Difficulty is set to yield blocks every 600s (on avarage), blobs are created (on avarage) every 40s and lumps (both blocks and blobs) every 37.5s.
Each lump yields a quantity R of lumpcoin, this changes over time but is the same for blocks and blobs, in addition, blocks collect transaction fees and blob fees.

Honest miners determine where to mine by selecting the chain with the most PoW (blocks have somewhat more weight) and try to include recent blobs. If everyone else does this, there is nothing to be gained by defecting, since (even without blob fees) including recent blobs benefits the miner by reducing the risk of a block being orphaned (it makes no difference for blobs, blocks can still be orphaned if several blobs are found before word of the block gets around, this can be fixed by giving more weight to blocks in choosing where to mine). Mining from blocks that are to be orphaned in the aforementioned manner is also stupid, since both blocks and blobs may be orphaned.

This system has some advantages over standard Bitcoin (the most obvious is finer distribution of coins) but more important is finer distribution of confirmation.
Assume, for now, that the block to blob weight ratio is 1+, (same weight, block wins in a tie, fresh block can be orphaned by 2 quick blobs, different ratios may be better).

Imagine Alice owns a coffee shop, Eve, who controls 10% of mining power, walks in and asks for a cup of coffee. She pays Alice with Bitcoin and Alice serves her the coffee after 2 confirmations (about 1200s). To reverse the transaction, Eve has to mine to catch up with the network, she is behind by 2 blocks (the math may not be right, I hope I can still get the point across), the chances of this are on the order of 1% (source: guess).

Now imagine Eve pays with Lumpcoin, as before, Alice waits about 1200s and about two blocks are mined. However, there are about 15 blobs in the second block, and all of them confirm the transaction. To reverse this, Eve has to catch up by 18 blobs, 1 block and 17 blobs, 2 blocks and at least 15 blobs, 3 blocks and 14 blobs, 4 blocks and 13 blobs, et cetera. In any case, she is behind by at least 17 PoW's and the rest of the network is chugging one out every 41.67s.
If the ratio is 2+ (3 quick blobs to orphan), Eve has to catch up by 20 blobs, 1 block and 18 blobs, 2 blocks and at least 15 blobs, 3 blocks and 13 blobs, 4 blocks and 11 blobs, 5 blocks and 9 blobs, 6 blocks and 7 blobs, 7 blocks and 5 blobs, 8 blocks and 3 blobs, 9 blocks and 1 blob or 10 blocks. However, options closer to the end of the list are increasingly unlikely and, in even the unlikeliest cases, she is still behind by 10PoW's.

You may ask what advantages this has over mining blocks more often (lower difficulty), the answer is that in, for example, DOGE, each block conflicts with parallel blocks and the result is a highly branched block chain, in Lumpcoin, blocks conflict with each other and, to an extent, with lumps, but lumps do not conflict with each other.

The lump string may also contain a block counter and a total lump counter. The lump reward R can be 1 lumpcoin for the first lump, 0.5 for the next 2, 0.25 for the next 4, 0.125 for the next 8, et cetera, thus maintaining relative scarcity while maintaining non-zero lump rewards to the end of time. To order lumps in one block, the block can come before the blobs and the blobs ordered by hash value.

Some things I am not clear on:
What prevents a miner from gaining more weight for his/her lumps without significantly changing difficulty (Bitcoin also has this issue?) by increasing the difficulty very slightly?
How is difficulty set in the first place?
What value is best for the fraction of lumps that are blocks?
What weight ratio is best? 1+? 2+? 16?
One issue I see is that a malicious miner may mine blobs and release them right after a block is mined, just to disrupt the network, is this a problem?

Bitcoin has a serious issue, the huge amount of work necessary to mine a block makes small-scale mining a lottery. This encourages miners to join mining pools, contributing to centralization. Large mining pools have far too much power over the block chain and may be vulnerable to hacking, corruption and rubber-hose attacks.

One way to fix this is to change the mechanism of mining, instead of having blocks each contain coins, have blocks contain only transaction fees and transactions include a PoW section that add coins to their address. To prevent miners specializing in coins or blocks (which would make the network less robust by reducing the block hash-rate), have the PoW look for coins and blocks simultaneously with different probabilities for each.

As an example, let me present...Dust!

The block-chain is much like the one for Bitcoin, with a few differences:
Each transaction has the following form:

SenderAddress Nuance1 CoinDifficulty Nuance2 Reciever1 Amount1 Reciever2 Amount2 . . . RecieverN-1 AmountN-1 RecieverN AmountN Signature

Now each part:
SenderAddress - The public key of the sender.
Nuance1 - Hash of recent transactions, hash of previous block, block difficulty, block height, ...
DustDifficulty - Set by the miner.
Nuance2 - Iterator, set by the miner.
Signature - A digital signature of the whole thing.
Recievers - Addresses.
Amounts - Self-explanatory, may include miner fees.

If the hash H(SenderAddress Nuance1 DustDifficulty Nuance2) starts with enough zeroes (set by DustDifficulty), the transaction is valid, and the DustDifficulty is added to the funds of the sender before the transaction. In this case, Nuance1 can just be included as a string of bits. Since the value of Nuance1 is irrelevant, the transaction can be submitted at any time and the PoW does not expire (if PoW expiration is desirable, the hash of the previous block can be included outside Nuance1, however, I think that lets large miners bully each-other and small miners). To avoid reuse, miners must keep track of either used PoW's or used addresses.

If the hash H(SenderAddress Nuance1 DustDifficulty Nuance2) starts with enough ones (set by BlockDifficulty), the sender just mined a block, the transactions included in Nuance1 are confirmed, and the Sender gets the fees, however the original transaction is invalid.

If someone wants to send Dust without mining, (s)he can set DustDifficulty=0 and just use an arbitrary string of bits for Nuance1, to avoid keeping track of other transactions or doing PoW (if (s)he just happens to "accidentally" mine a block, it will be invalid).

In this scenario, every "particle" is worth one hash evaluation, hence the name "Dust," so it appears that the price would stabilize at the energy cost of one hash, I am not sure if more scarcity can be practicably enforced.


Pros of Dust over Bitcoin:
-No incentive to pool.
-Anyone can easily make a few particles to play around with.
-Weak scarcity allows use for anti-spam PoW.
-Can be spent painlessly do to ease of manufacture.

Pros of Bitcoin over Dust:
-Scarce.


Can the general idea of separate blocks and coins have any application?

Is Dust practical?

Has anyone thought of this before?