BitCoin is a distributed crypto-currency. General questions about bitcoin, other crypto-currencies and their environment not directly relating to security are better suited for bitcoin.stackexchange.com

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18
votes
5answers
935 views

How can I explain “zero knowledge proof” to an end user?

A ZKP allows proof of knowing the answer to a secret, without actually disclosing what that answer is. Is there any analogy that can help people put this concept into everyday practice? A "lie to ...
5
votes
1answer
127 views

I have been hacked and im not sure how — Ubuntu 14 VPS, crypto wallet [closed]

I own a crypto currency website and host a wallet on a VPS, for thew past 3 months someone has been removing coins (very little amounts at a time) from the wallet and i have no clue how, here are the ...
5
votes
1answer
85 views

How does combining SHA256 with RIPE-MD160 compare to SHA256 + SHA-3?

Bitcoin stores its addresses as a combined SHA256 + RIPE-MD160 hash. Is it correct to assume this is done to prevent a failure in the algorithm? Since SHA3 was designed to be an alternative to ...
3
votes
2answers
96 views

DoS attacks and bitcoin

I was wondering what the repercussions were if a Bitcoin exchange or website that holds bitcoins were to succumb to a DoS attack. In my understanding, all a denial-of-service attack does is deny ...
0
votes
1answer
64 views

Can a Bitcoin miner generate SHA2 hashes on arbitrary data?

I'm not asking about bitcoin's design...but am interested in the hashing capacity of a bitcoin miner. To be short: do bitcoin miners(or some of them) accept customizable inputs and hash them in ...
1
vote
1answer
42 views

Implement GPG Verification (Bitcoin-OTC)

I'm looking to implement a "Verify with Bitcoin-OTC" feature for my web app. The general idea is the user would prove he owns a particular account on the external site Bitcoin-OTC and my app would ...
1
vote
1answer
56 views

Keeping signatures valid even after the private key has been compromised

If I understand the topic of digital signatures correctly, you sign a message via hashing+encrypting it using your private key. Then, if a private key is compromised by an attacker, she could sign ...
17
votes
4answers
3k views

If you send a bitcoin payment to a seller, will they learn your IP address?

Since you send bitcoin payments through one of the Bitcoin clients, I assume it announces the payment to the network, so each computer it connects to in order to do so would know the IP address from ...
5
votes
2answers
113 views

which memory hard hashing algorithm can equalize low-computational and high-computational power devices to utilize blockchain in the IoT?

Recently IBM and Microsoft showed their interest (IBM post, Microsoft post) in utilizing bitcoin's blockchain for internet of things (IoT) development. Let's assume that in close future the blockchain ...
6
votes
3answers
231 views

Any way to prove that two devices are in the same physical space, for authentication?

I need to come up with digital proof that two physical devices are in the same (approximate) location whenever that transaction occurs. This could be: A digital ID and the authenticator A consumer ...
2
votes
1answer
70 views

Bitcoin and fraudulent transactions

I was reading Police suspect fraud took most of Mt. Gox's missing bitcoins, and its effectively claiming the missing 650,000 bitcoins vanished: Of the 650,000 bitcoins unaccounted for -- worth ...
0
votes
1answer
142 views

blockchain.info exploit - Random number flaw

"The problem that led to the vulnerability was reportedly wallets generated with previously used 'R-values' in formulas that generate random numbers, meaning a hacker could use the public ...
3
votes
1answer
107 views

Offline phone security

How secure is an offline android phone? Some background. I want to use an app called Bither on android, which allows me to create a cold wallet on 1 phone and a hot wallet on another phone. Cold ...
0
votes
2answers
145 views

How would you set up a ‘cold’ netbook for master-key signing, large Bitcoin transactions, etc? [closed]

I've just ordered a cheap-o netbook on Amazon, with the intention of installing a Linux distro, and turning it into a permanently-offline high-security machine for sensitive tasks. However, I'm no ...
0
votes
2answers
87 views

Why don't sites implement a system where a wrong password causes a 3 second delay?

I am into bitcoin right now, and the password threats scare me a little... Not so much for me, because I use LastPass and generate new passwords at 20 characters and it includes symbols, upper and ...
1
vote
1answer
112 views

Tiny USB sticks

To store my Bitcoin safely, I have an offline transaction setup. Computer A is online with a copy of the blockchain, and computer B is offline with the private keys. To make a transaction, I craft it ...
0
votes
1answer
46 views

Is a government entity capable of establishing a secure virtual currency system? [closed]

After reading about BitCoins, I can't help but contemplate the idea of the a government withdrawing paper money and bringing all currency transactions digital, via a bitcoin-like method where every ...
1
vote
1answer
105 views

Anonymity of Bitcoin

I just asked myself that when you have bitcoin network, which is as we know "pseudo" anonym. Because of the transaction logs of the network (which are afaik endless), it seems that transactions are ...
0
votes
1answer
145 views

compromising DVRs to become bitcoin mining bot [duplicate]

I read this article, about an exploit which highjacks a DVR to become a "bitcoin mining bot". The heart of the attack is to send a binary using just echo comands to the device, which acts as a ...
0
votes
2answers
110 views

Is it safe to use a ECDSA public key as a password seed for GCM/AES?

Two peers already exchanged their ECDSA (curve secp256k1) public keys using a secure channel. They want to establish an authenticated encrypted channel between them. They will use CCM mode and with ...
0
votes
1answer
277 views

Can I use crypto.getRandomValues to create a private key?

In the window.crypto spec: http://www.w3.org/TR/WebCryptoAPI/#RandomSource-interface It says explicitly: "Do not generate keys using the getRandomValues method. Use the generateKey method ...
8
votes
4answers
922 views

Is webRTC safe against man in the middle attacks?

We are implementing an open source software package (copay, a multisig bitcoin wallet), that uses peerJS, which uses webRTC to allow peer-to-peer communication between browsers. peerJS (and webRTC) ...
-2
votes
2answers
118 views

Could a network host and process programs while securing against piracy?

Consider an ideal service hosting network, which: Lets programmers: Publish a program in such a way that it can't be retrieved. Associate a program with a wallet. Specify a cost per request and ...
1
vote
1answer
109 views

Minimum SHA256'd UTF8 encoded passphrase length not stored anywhere

For a passphrase that is UTF8 encoded and then SHA256'd, what is the minimum length to achieve a practically collision free result? The implementation is for a 32 byte cryptocurrency ed25519 seed ...
12
votes
1answer
503 views

Is the Litecoin Scrypt hashing technique a threat to hashed passwords?

The Bitcoin alternative, Litecoin uses a different algorithm to protect the block chain, namely Scrypt (not Sha256). Given that GPU accelerators exists, and ASICS are due to be released, does the ...
14
votes
2answers
990 views

Are there any tell-tale signs of self-hacking? [closed]

After the Mt.Gox crash, and also keeping in mind recently published attacks on Target and Neiman Marcus, one is led to believe that sometimes so-called hacking is perpetrated by insiders. What are ...
0
votes
1answer
215 views

Building an VM with Vagrant and connecting with ssh+2FA to protect a bitcoin wallet?

I would like to try to build a Virtualbox image to use with Vagrant. This is the features: Login with SSH + 2FA (Google Auth) No X No internet connection Copy unsigned transaction, sign it and ...
1
vote
1answer
92 views

Ideal cryptocurrency digital signature

What are the characteristics of the ideal digital signature for cryptocurrency transaction verification? The reason I ask is because this answer about bitcoin signatures describes a potential ...
10
votes
3answers
12k views

With ASIC bitcoin miners, should SHA256 be considered insecure for password hashing?

I'm sure everyone here has seen the rise and further rise of bitcoin. The process used for mining bitcoin is basically "let's brute force an SHA256 hash that is less than this amount" That being ...
11
votes
3answers
10k views

Detect Bitcoin Mining

So, me and a network administrator friend were discussing about bitcoin mining. With so many portable bitcoin mining software, we wanted to find the different ways to detect them in the network. How ...
6
votes
1answer
594 views

Safest way to keep an offline bitcoin wallet

Keeping a large amount of bitcoins in an online computer is dangerous. The bitcoin wallet is merely a file, and once the file has been copied the bitcoins can be transferred to another account. ...
1
vote
2answers
1k views

Best practices for operating a Bitcoin-Qt client regarding netwok privacy?

As privacy is part of security, I know there is a Bitcoin SE here but they couldn't answer my question so I hope it's appropriate to ask it here. I don't ask about how to secure my wallet on my ...
10
votes
6answers
2k views

Security of SHA256 and Bitcoins

The Bitcoin network use SHA256 as a core component to it's design. I'm no expert on cryptography, but it seems to me it usually is only a matter of time before security vulnerabilities are discovered ...