Security issues with the design or implementation of Bitcoin and related crypto-currencies.

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1answer
31 views

Reuse of addresses by a service (“get new address” returning *funded* addresses)

Recently, a marketplace was said to have been reusing deposit addresses, such that clicking the "get new address" button would immediately give the user a different address, however, the "new address" ...
2
votes
1answer
84 views

Who pays me when pool mining?

When I pool mine, do my payments come from the pool operator's personal account? From the pool's wallet? Or from somewhere else? When using P2Pool, the payments appear in bitcoin-qt as though I had ...
1
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0answers
15 views

Do any router custom firmwares enable Bitcoin for anonymous usage?

I want to find Wifi firmware where I can sell my internet service with anyone who needs to use it... ideally paying in an Altcoin or Bitcoin. Are there any router modifications that support a wallet ...
4
votes
2answers
116 views

How can services that use the bitcoin blockchain help secure it?

There are many projects being worked on that involve using the bitcoin blockchain for its public verifiability and immutability. A few examples would be Counterparty, Medici, Factom, etc. But each use ...
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2answers
49 views

Is an unencrypted wallet secure if bitcoind is not accepting RPC calls?

I'm interested in setting up a P2Pool node (which requires running bitcoind) to run a little mining pool for myself. Before you ask, nope I'm not even trying to break even, I know I'll lose money on ...
0
votes
1answer
95 views

As of Feb 2015, what's the most technically secure wallet for Android?

I want a wallet on my Android phone that is rooted. I'm new to bitcoins and I'd like to know which one is technically secure...if it helps, I'll be buying Canadian bitcoins.
0
votes
1answer
49 views

Pseudo-Node and putative attack vectors on the network

Pseudo-Node is discussed here on Reddit's /r/Bitcoin Essentially it functions to relay calls from connected nodes in a random fashion. This was an experiment into how easily can full nodes be ...
4
votes
2answers
75 views

Intercept and edit transaction output

When a P2PKH transaction is created there are two main parts: the transaction input and the transaction output. I understand that the transaction input requires a signature that unlocks a previous ...
2
votes
2answers
174 views

Can an attacker create many nodes that approve blocks without work?

There are currently about 7000 nodes in the Bitcoin network. The security rests on the fact that someone adding nodes would have have to expend CPU power to hash transactions. What prevents someone ...
2
votes
3answers
128 views

Can an exchange work which does not have control of the private keys?

It seems like there is really no great way to exchange USD for BTC. Having to trust an exchange with your private keys is undesirable. I'm wondering if there is a way to utilize the convenience of ...
5
votes
2answers
316 views

Proving a transaction is mine

As an assignment in a digital security course, a group of 100 students was asked to transfer a small amount in bitcoins to a certain wallet. They promised they'd buy something for us from this money. ...
4
votes
4answers
3k views

Did I just create counterfeit bitcoins?

I had 3 Bitcoins stored on my PC and I had a backup image of my PC. I restored my PC on another computer from the image and I had 3 Bitcoins on that computer also. I spent 5 Bitcoins as a test, and it ...
4
votes
2answers
208 views

How could a time warp attack be prevented?

jarpian explains what a time warp attack (AKA zeitgeist attack) is: This is a 51% attack where the attacker sets the block timestamps artificially to lower the difficulty, allowing him to profit ...
0
votes
1answer
42 views

How can I be sure that bitcoin mining software is not compromised?

I have been interested of generating Bitcoins but how can I be sure that the software that is available for this is not somehow compromised? My concern is that the software may have some backdoor ...
1
vote
1answer
37 views

Confirmed transactions lost in my synchronised node

I tried to get a transaction information using RPC method getrawtransaction in my synchronized node, but I got no information about the transaction. I did it in another node, and I could get the ...
2
votes
1answer
85 views

How resilient are Proof of Stake (PoS) mechanisms to brute force quantum computing attacks?

The article called "Bitcoin vs. The NSA’s Quantum Computer" was a great read pertaining to Bitcoin, and computing minimum thermodynamic energy required to brute force attack public key to discover the ...
1
vote
2answers
95 views

How does Ripple ensure that transactions take place

I am struggling with some concepts in the Ripple system. As I understand it: After an American user goes to a gateway and loads $ into the Ripple system that he wants to send to Cambodia, the ...
1
vote
1answer
80 views

Encrypting Bitcoin private keys instead of printing out paper

I follow the procedure of making a cold storage wallet: downloaded copy of bitaddress.org using an off-line computer booted with Ubuntu from CD. Instead of printing out the private keys and ...
3
votes
1answer
102 views

Technical analysis of Blockchain.info security breach

I the news I read this: The firm was forced to make a security disclosure on its blog and on Reddit, admitting that a development error had led to a problem with the generation of private ...
1
vote
1answer
27 views

Funds and Wallets

If I load bitcoins to my wallet and the funds are there, and I go back to load more Bitcoins with a new address for my wallet are the funds from my first wallet going to merge with the newly added ...
1
vote
1answer
76 views

Lower confirmation time schemes: any requirement between confirmation time and the probability to find a block during that confirmation time?

Bitcoin, the first blockchain-based cryptocurrency, set a 10 minute confirmation interval time; LiteCoin set a 2 minute confirmation interval time; DogeCoin set it at 1 minute; QuarkCoin set it at 30 ...
1
vote
0answers
59 views

Which exchanges support U2F authentication?

I got myself a nice security key (Yubico Fido) today, which utilises the U2F protocol. But to my surprise not a single Bitcoin exchange seems to support this yet, only Google itself. So which ...
0
votes
1answer
97 views

Why are non-final transactions considered non-standard?

In IsStandardTx within main.cpp, there is a comment: // Treat non-final transactions as non-standard to prevent a specific type // of double-spend attack, as well as DoS attacks. (if the transaction ...
1
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3answers
170 views

ECDSA x,y coordinate validity verification doesn't seem to work

The ECDSA algorithm, secp256k1 for Bitcoin allegedly uses the equation y ^ 2 = x ^ 3 + 7 mod P to determine the validity of an alleged point upon the elliptical curve. Utilizing ...
6
votes
1answer
212 views

Is there a fallback plan if bitcoin's underlying cryptography is cracked?

Lets say someone started making real viable quantum computers that were affordable enough that large companies could buy one. And lets say a quantum algorithm was devised to crack the private keys of ...
1
vote
2answers
168 views

Why don't any of the SHA-256 vulnerabilities matter for mining?

Wikipedia lists several vulnerabilities in SHA-256. Presumably, none of them can be used to mine faster, or it would be done already. Why don't these vulnerabilities lead to a problem for mining?
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2answers
50 views

Profit possibility for colluding with 51% attacker

The Bitcoin Wiki states "A profit-seeking person will always gain more by just following the rules, and even someone trying to destroy the system will probably find other attacks more attractive." ...
3
votes
1answer
68 views

Can side chains or “pegged” chains negatively affect the security of Bitcoin?

Regarding the concept of side chains or "pegged" chains which has been discussed since as early as 2011 and explored in this white paper, how can these negatively affect the security of Bitcoin? ...
3
votes
1answer
140 views

How to generate a public key from a private key using Elliptic Curve Digital Signature Algorithm

I'm trying to understand the graphical basis that underlies the discreet logarithmic Elliptic Curve Digital Signature Algorithm (ECDSA) introduced in Chapter 4 of "Mastering Bitcoin" by Andreas ...
1
vote
2answers
207 views

How does a Trezor passphrase prevent restoration of a wallet if an attacker knows the seed?

Trezor User Manual says if you forget the passphrase there will be no way to recover your bitcoins. Not even the Recovery seed. How is it that you (or an attacker who knows the seed) can't just ...
2
votes
2answers
224 views

Can a Trezor seed be used in any other HD wallet?

Trezor FAQ says If you do not use a passphrase, your recovery seed is all that is needed to access your bitcoins. If you do not use a passphrase, can the Trezor seed be used to recreate a ...
3
votes
2answers
129 views

What is it about a Trezor that means it can't be infected by malware?

The Trezor testimonials include that TREZOR ... cannot be infected by malware What is it about a Trezor that means it cannot be infected?
2
votes
3answers
221 views

How can an online wallet be more secure than paper wallets or cold storages?

Recently, after I was reading that some bitcoin early adopter lost 750 BTC due to theft from his macbook, I was looking for the most secure storage solution for my coins. I already know about paper ...
0
votes
1answer
51 views

How can address' hash160 be used to determine information for malicious purposes? (Ie reusing of the same address)

I've been playing around with Richard Kiss's Pycoin app which is clarifying how P2PK works. I see that the hash160 of the value: (0x04) (x-coordinate) (y-coordinate) (for an uncompressed Testnet ...
0
votes
2answers
55 views

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 ...
1
vote
2answers
109 views

Can you encrypt not just the private key, but also the public keys (ie bitcoin addresses) in an Armory wallet?

I would imagine that the paranoid darknety bitcoin user has an interest in keeping not only their private keys safe (so nobody can steal their bitcoins), but also has an interest in keeping their ...
1
vote
2answers
49 views

Theoretical security of mining bitcoins

Is it possible to change rules of mining bitcoin division? rewrite P2P bitcoin client (or write maleware) which will be pretending that fake bitcoin client is legal, original client distribute ...
0
votes
1answer
37 views

How do I reset my TFA token in Coinbase?

I would like to move my Coinbase Two-factor authentication token from one device to another. I cannot find a location on their website to disable TFA once it has been set up, or to move the token to ...
2
votes
1answer
58 views

How secure is calling bitcoind JSON-RPC from same computer?

I am wondering if calling JSON-RPC from the computer it is running on is secure. I read How secure is calling bitcoind JSON-RPC? and understand why it is insecure to do so from a different computer. ...
1
vote
0answers
86 views

Standardize wallet format [closed]

What's the status of wallet format standardization? Is there any proposal or work-in-progress around? If not, how come nobody urges to define standard wallet formats yet? This is especially needed ...
3
votes
1answer
367 views

New to Bitcoin - tips on securing my server

I regard myself as being a competent programmer and have good general IT knowledge; however I know very little about BTC. I just want to make sure that my setup is "generally secure" and that I'm ...
2
votes
1answer
113 views

How to securly move bitcoins from a wallet.dat file to a paper wallet? [duplicate]

I have an old wallet.dat file with a few Bitcoins. It is stored in an isolated computer that is not connected to the internet. I would like to get rid of the wallet.dat file, and move all the ...
1
vote
0answers
73 views

How do mnemonics encrypt wallet data and what prevents hacking of the algorithm?

How do mnemonics encrypt wallet data and what prevents hacking of the algorithm? For example Blockchain seems to encrypt all data using a mnemonic yet doesn't hold customer data server side. What ...
1
vote
1answer
120 views

How does CryptoNote prevent a 51% attack and double-spending?

How does CryptoNote prevent a 51% attack and double-spending? I’m interested to know what is the mechanism that protects CryptoNote coins from 51% and double-spending attacks.
0
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0answers
22 views

Ensure Wallet consistency

I have recently migrated machine. I used the Apple Migration Wizard and when it was finished my new machine's copy of Multibit appears to have my BTC within it. My next task is to wipe the old ...
2
votes
1answer
105 views

What is Mt. Gox's YubiKeys' “configuration protection access code”?

Does anyone know if Mt. Gox, now that they're bankrupt, has released their YubiKey's "configuration protection access code" (cf. this)? If so, we could reprogram the free YubiKeys they sent us and use ...
3
votes
1answer
94 views

What are some of the pitfalls of a 100% proof of stake currency (pos) like NXT?

Bitcoin has the vulnerability of a 51% attack for a proof of work currency, but what pitfalls does a 100% proof of stake (pos) currency have like NXTcoin?
2
votes
1answer
98 views

Bitcoin security, what is wrong with my thinking? [duplicate]

Lets assume I keep generating random public keys with their matching private keys and never use them. Severals years later I am checking for positive match against the blockchain for all my generated ...
6
votes
2answers
158 views

Does GHashIO already have above 51% hashrate?

Right before writing this question I noticed the GHashIO showing 32% hashrate distribution using the following link. Unknown has 26%. And the IP address of the most blocks reported from unknown is: ...
5
votes
4answers
2k views

Supermajority to prevent 51% attack?

I would think that amending the bitcoin protocol to require a supermajority, say 60% or 75%, to verify proof of work help reduce the risk of a 51% attack. If this is so, what are the major obstacles ...