Concerning the broad subject of cryptography and its narrow application in Bitcoin protocol and applications.

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Hash property resistance

I'm experimenting with some self study cryptography and I was curious about the two following scenarios (simple answers and/or in relation to bitcoin) If SHA256 was found to lack pre-image ...
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1answer
22 views

What is the algorithm used to sign data within Nxt?

I understand that Nxt uses Curve25519 to generate pubkeys for user accounts, however, I can't find a reference that states what which signing algorithm/process is used for transactions and blocks. ...
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1answer
50 views

What exactly is generator G in Bitcoin's elliptical curve algorithm?

Given an elliptic curve u = k r, the generator G is This generator G is typically described as point on the curve. But what exactly is this value G in programming terms? Is this a tuple of values? ...
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1answer
68 views

Anonymous transactions technology for a cryptocoin? [duplicate]

I’m thinking of investing in a cryptocoin with anonymous transactions feature. So far there are 3 well-known technologies for that: coinjoin (Bitcoin), masternodes (Darkcoin) and CryptoNote ...
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3answers
84 views

Which cryptocurrencies deviate significantly from Bitcoin?

There's been dozens of alternate cryptocurrencies but I don't believe many of them did much other than find/replace some strings. We see Bitcoin as made up of the blockchain and proof-of-work via ...
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1answer
58 views

Bitcoin related research areas [closed]

I have a one year research project in my MSc curriculum. So i was suppose to address a existing issue in bitcoin protocol. Highly appreciate if someone can advise me and give me some ideas. Thank ...
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0answers
58 views

Multisig transactions vs secret sharing

Some background here, I am implementing a wallet that enhances security by using smart cards. The card stores a pin protected key but unfortunately cannot do ECDSA signing. There is also a server ...
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2answers
80 views

Are Bitcoin Block Hashes Predictable

to create the block chain, the Bitcoin network runs hashing algorithms for each block, is it mathematically possible to predict the hash value of say, the 100th block from the last block currently in ...
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8 views

Crptoarbitrer gem shows infinity and zero to crptocoin exchanges

I am using Crypto Arbitrer gem for finding the price amount to buy and sell some coins. It is said that it supports (btc ltc nmc nvc trc ppc ftc cnc) the mentioned coins. But when i check it does not ...
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1answer
51 views

Should I use a large random value for i in BIP 32 instead of sequential?

BIP32 doesn't have any guidance on how to choose the i value for child keys. Is there any benefit to using a random value for i ? Other than documenting and saving the value of I for various ...
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1answer
141 views

What are the weakest cryptographic guarantees in Bitcoin?

I read in this Github pull that Bitcoin relies on weaker cryptographic guarantees than SHA256. What are the weaker cryptographic guarantees being referred to? Could it be that RipeMD is 160 bits? ...
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3answers
300 views

How can a bitcoin exchange prove its solvency while maintaining privacy?

What methods can an exchange website use to prove that it actually has all its users' bitcoins? These are the requirements: User privacy is a must. No one should be able to tell how many bitcoins ...
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1answer
154 views

Is Electrum Cryptographically Secure?

Electrum seems very user friendly, thin and convenient, but is it cryptographically secure? One of the ways to attack any cryptographic system is to exploit weaknesses in the key generation ...
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1answer
67 views

ECIES - When is it bad to sign and encrypt using the same keys?

Suppose I have a public key for a particular user (perhaps extracted when using the new public key recovery format included in P2SH, and BIP32 transactions). Is it OK the same key for both signing ...
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3answers
236 views

Why is Bitcoin better than other cryptocurrency? [duplicate]

If there too many types of such kind of currency, will them be very cheap? I have 4 BTC and since the current BTC price waves a lot, I am wondering this. Thanks,
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1answer
92 views

Is there a signature format, or cryptography has *only one* possible S value?

EDIT: This question is not specific to Bitcoin. It's applicable to any other crypto currency that is interested in using a different signature scheme than Bitcoin or the QT reference client. One ...
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1answer
1k views

What does the curve used in Bitcoin, secp256k1, look like?

I'm reading up on ECC curves and on many of them I see an illustration that looks like this What does the comparable curve in Bitcoin look like, or are all curves generally the same?
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0answers
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Does Amit Sahai's indistinguishability obfuscator enable Autonomous Virtual Corporations or “Agents”?

Given that an "Agent" is described as Agents are autonomous programs that maintain their own wallet, which they use to buy server time. Money is obtained by the agent selling services. If demand ...
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2answers
522 views

How does this OpenCL BTC private-key cracker work? Is it a real threat to bitcoins?

I am specifically referring to this over at bitcointalk.org. The general consensus I gathered from reading the thread is that this is not a hoax. There seems to be a group of generated bitcoin ...
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71 views

Multibit: Using the same passphrase for both my wallet and exported private keys

I have a password-protected wallet in Multibit that I have backed up in multiple locations. I have exported the private keys from this wallet. The private keys are password-protected using the same ...
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1answer
108 views

Are transactions still tamper-proof if blocks are hashed without nonces?

If an alt were to forgo difficulty and timed release of new supply by removing the nonce from blocks therefore the whole difficulty/target system, is hashing without nonces still providing the same ...
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1answer
134 views

Why are blocks hashed?

Am I correct that addresses are hashed to compress a huge text-represented coprime into something of manageable size? Am I also correct that transactions are hashed for the same reason and also ...
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1answer
159 views

What is the Elliptic Curve algorithm used in Ripple to generate public / private key pairs?

The algorithm used by bitcoin to generate keys is secp256k1, is it the same for ripple?
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2answers
235 views

Is it possible to use a PGP key as a bitcoin address?

Both bitcoin and encrypted emailing are based on public key cryptography. However, they use different implementations, so I assume that a public PGP key cannot be used as a bitcoin address directly. ...
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3answers
734 views

What is the problem that mining solves?

Of course, the function of mining is to secure the blockchain, but I'm looking for a more abstract summary of what the exact problem is that mining tries to solve? I believe its called the Byzantine ...
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1answer
697 views

Step by Step - how does sending 1 bitcoin work?

I've been reading about how BitCoin works for a few weeks now - and I'm trying to understand under-the-hood how the cryptography works. So i'll explain what I know at the moment - and if someone ...
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1answer
330 views

What are the advantages of using Secp256k1?

Bitcoin uses secp256k1 as the specification for it's address system (https://en.bitcoin.it/wiki/Secp256k1). What are the advantages (and disadvantages) of using this over other specifications such as ...
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1answer
107 views

What is the ECC key length for OpenCoin's implementation of Ripple?

http://www.reddit.com/r/Bitcoin/comments/1lubl1/wired_oped_worries_that_elliptic_curve/cc2vhos suggests that key lengths < 500 bits are no longer considered secure from the NSA. What key length is ...
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2answers
366 views

Litecoin formal description

Is there a paper with a formal description of a Litecoin? And a paper explaining what a miner does? I would like to understand how to mine "manually", I mean I dont need a tutorial on how to install ...
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1answer
228 views

The compressed public key byte header

I've noticed that compressed public keys are always either 0x02 or 0x03, but what exactly determines whether it's 0x02 or 0x03? I can go look at the OpenSSL code to answer this, but I'm hoping someone ...
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39 views

Future treasure hunters [duplicate]

Would it be possible and economical in the far future to look for addresses abandoned in the early years of Bitcoin and then brute force their private keys? In the near future the usual argument goes ...
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1answer
259 views

Recovering the last few digits of a Litecoin private key

Is it possible to recover the last few lost digits (10) of my Litecoin wallet private key? Are there any recovery tools available? Or will I have to try and roll my own? Crucially, what crypto ...
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2answers
1k views

Economics of Bitcoin Mining [duplicate]

I thought I understood the gist of what "bitcoins" are: electronic currency tokens representing $X USD that could be used to trade, buy or sell online items. But recently I heard the term "mining for ...
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1answer
287 views

Address Public Private key verification [duplicate]

Apologies if this question has been asked before, but when a bitcoin client wishes to send funds to an address, does the bitcoin protocol force the client to verify that the address has a ...
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1answer
207 views

What standard is used for the ECDSA to verify transactions?

Bitcoin used Elliptic Curve Digital Signature Algorithm. (see here). I'm wondering what standard is actually used for this Algorithm: which curve? which prime? Can anybody give me a reference? (Wiki ...
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2answers
151 views

When will the public key of an address used in the network?

On block explorer there are some address with public key available, and some without. (e.g. this one has public key: http://blockexplorer.com/address/1HBheYzvX7NDtcwVrMS7gxReNRVezYS7w2 , and this ...
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1answer
1k views

How does bitcoin work from a technical computer science cryptography perspective?

How does the cryptography science behind bitcoins work to make it robust(reliable , scalable). I am interested in technical explanation with cryptography math and not just conceptual explanation.
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Can there be Bitcoin-like network that also works as whatever@home? [duplicate]

There are Bitcoin-like network that performs calculations that are not locally useful, but interesting for peers. There are {SETI,folding,...}@home networks that calculates something that is ...
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2answers
1k views

If SHA256 and/or RIPEMD-160 were broken, would all bitcoin addresses be compromised?

If not, what else would be needed to steal all funds from all people and completely break bitcoin? I bet some will say ECSDA gives bitcoin an additional layer of protection. I counter this by saying ...
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1answer
194 views

How can I use message signing to prove that I have private keys for many different accounts?

I want to prove the total sum of BTC I have access to. Therefore I think if I use message signing to assert "owned by makerofthings7" in each address, then anyone can compute the total coins in my ...
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4answers
7k views

Bitcoin Mining ASICs used for cryptographic application? Rainbow tables?

What is the potential that the ASICs being developed for mining could be used for other cryptographic applications such as building rainbow tables? I know that for instance those that crack GSM with ...
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1answer
184 views

Does a Vanity Address reduce the randomness / entropy of the private key? Is there cryptographic proof?

Since a vanity address discards many "valid" keys in order to find one that matches a pre-determined string, I think that the "randomness" of the data would be reduced, thus weakening the key. Is ...
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1answer
351 views

What OpenCL video cards (or FPGAs) are best for multiplication?

I'm benchmarking some Bitcoin related software and am looking for cards that are better at parallel multiplication vs parallel addition. Is there any prior work that may have this information? ...
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357 views

Do vanity addresses lower the security of my key? (reduced complexity)

Do vanity addresses somehow decrease the security of my private key?
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1answer
447 views

What mathematical property links the Armory chain to the public/private keys?

According to the Armory site the Public Keys needed for the Bitcoin addresses can be generated without having access to the Private Keys, which ideally are stored on a completely different computer. ...
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6answers
2k views

Which Bitcoin-powered gambling sites are “provably fair”?

Through the spread of Bitcoin for the purposes of online gambling, the concept of "provably fair" games came more into the limelight. Which of the Bitcoin-powered gambling websites are provably fair? ...
5
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1answer
473 views

Where and how is secp256k1 used within Bitcoin?

Bitcoin is unique that is uses secp256k1 to secure it's transactions; and any cryptographic attack against this algorithm is probably going to be percieved as an attack against the bitcoin network. ...
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1answer
295 views

Bitcoin Research

I have recently been assigned to advise a student on a senior thesis in math. She has taken linear algebra, introductory real analysis, basic cryptography, and abstract algebra. Her interest is in ...
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54 views

How secure is a private key? [duplicate]

Possible Duplicate: Is it possible to brute force bitcoin address creation in order to steal money? I've tried brainwallet.org and now I wonder, what happens if someone starts to generate a ...
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3answers
4k views

What is a compressed Bitcoin key?

The standard Bitcoin client in version 0.6 apparently introduces compressed keys. What are they? Are there any drawbacks to using them? Any incompatibilities with older software? Reductions in ...