• Breaking News

    Saturday, February 2, 2019

    Home Unlabelled BTC PSA: Electrum and Electron Cash servers are being Sybiled -- AGAIN!

    BTC PSA: Electrum and Electron Cash servers are being Sybiled -- AGAIN!

    February 02, 2019

    BTC PSA: Electrum and Electron Cash servers are being Sybiled -- AGAIN!

    PSA: Electrum and Electron Cash servers are being Sybiled -- AGAIN!

    Posted: 01 Feb 2019 03:33 PM PST

    If you're running the SPV client Electrum (for Bitcoin) or Electron Cash (for Bitcoin Cash) know that ElectrumX servers are being sybilled (again!).

    Presumably the phishers are up to their old tricks of tricking users to install a malware version of their client.

    BUT We at Electron Cash have already put countermeasures in place.

    MAKE SURE you are running the latest version of Electron Cash. Get it here: https://www.electroncash.org.

    The latest version of Electron Cash will:

    1. Never allow server-side strings to spam you with bogus alerts to download an update
    2. Allow you to use the "Preferred Server" feature -- the client will only connect to "trusted" servers. If you are running the latest version be sure to turn this on. It's in the network settings:

    https://imgur.com/7buPdwp

    So get the latest 3.3.5 Electron Cash, and turn "Preferred Servers only" on, and have peace of mind. :D

    EDIT: Words. Typos.

    submitted by /u/NilacTheGrim
    [link] [comments]

    PayPal Co-Founder Admits Original Mission of PayPal Was Creating A ”Global Currency” Much Like Cryptocurrency

    Posted: 01 Feb 2019 08:39 AM PST

    YouTube pulls Rogan/Dorsey (twitter ceo) podcast right as blockchains disruptive potential was being discussed

    Posted: 01 Feb 2019 09:11 PM PST

    BITCOIN CASH (BCH) Buys Real Goods and Services with ANYPAY

    Posted: 01 Feb 2019 11:51 PM PST

    Make no mistake, this is what bitcoin cash is.

    Posted: 02 Feb 2019 12:26 AM PST

    The Kraken team has a massive opportunity to offer BCH/CAD pairing! Let’s show @krakenfx how much the #BCH community in Canada would appreciate this! #BitcoinCash |

    Posted: 01 Feb 2019 12:16 PM PST

    If you believe that anarchy is NOT the answer, then....

    Posted: 01 Feb 2019 03:51 PM PST

    the only other option is to believe that some people get to use violence against peaceful people who haven't aggressed against anyone. There is no middle ground.

    Please watch this 4 minute video and ask yourself "when do you think it is ok to aggress against George?".

    submitted by /u/MemoryDealers
    [link] [comments]

    A leading Canadian exchange has been locked out of its crypto cold storage holding $145M

    Posted: 01 Feb 2019 11:52 PM PST

    BCH now on Anypay! #BCH #Retail #Adoption https://anypay.global

    Posted: 01 Feb 2019 09:49 AM PST

    PSA: Warn: I have detected an advanced camouflaged shill spinning up new narrative. Please take note in order to detect such incidents in the future.

    Posted: 01 Feb 2019 04:03 PM PST

    This is the post in question:

    https://old.reddit.com/r/btc/comments/am2vc3/am_i_really_in_the_minority_in_this_sub_with_the/

    I have verified the poster's account and I am sure that he is a (very advanced and well camouflaged) CSW Shill.

    My certainty level about this fact: Absolute.

    Therefore, the narrative being created here is with very high certainty a fake(spinned/astroturfed) one and the user cannot be trusted to be a honest part of this community.

    Please take note in order to more easily detect & neutralize such incidents in the future before they get out of control.

    submitted by /u/ShadowOfHarbringer
    [link] [comments]

    Switzerland-based Cybersecurity Firm Starts Blockchain Center in Geneva

    Posted: 01 Feb 2019 09:27 PM PST

    Am I really in the minority in this sub with the belief that anarchy is NOT the answer?

    Posted: 01 Feb 2019 07:03 AM PST

    I mean, call me crazy, but I do not believe that bitcoin's purpose is to overthrow representative government and replace it with a theoretical anarchocapitalist society. But BCH's celebrities, mainly /u/chrispacia and /u/memorydealers , seem to consider bitcoin and anarchy to be inseparable, or at the very least, they see bitcoin as the means to the end that is anarchy.

    It can be enough of a headache trying to educate people about bitcoin's use cases as electronic p2p cash. I refuse to also spend time convincing people of anarchy's merit.

    Anarchy is becoming synonymous with BCH and r/btc in general, and it is not a good look. Espousing anarchistic principles is a means to this community's isolation, NOT bitcoin adoption.

    I'm frustrated, but I feel like there's no way that a majority of silent observers in this sub are anarchists. If so, I think the community has been led astray.

    submitted by /u/thedailymath
    [link] [comments]

    If you believe in government, then you also believe your Bitcoin is one executive order away from being rightfully stolen.

    Posted: 01 Feb 2019 11:08 AM PST

    When you don't have kids ���� #powercouple #BTC

    Posted: 01 Feb 2019 04:21 PM PST

    Anarchapulco Returns Promoting Freedom and Cryptocurrencies - Bitcoin News

    Posted: 01 Feb 2019 07:54 PM PST

    Today we completed 411 days of Bitcoin bear market, we match the bear market 2013 to 2015

    Posted: 01 Feb 2019 06:33 AM PST

    Today is a party day, haha

    ​

    Today we completed 411 days of Bitcoin bear market, we match the bear market 2013 to 2015

    ​

    Tomorrow we will beat the WORLD record and we can enter the Guinness book

    ​

    I have waited a long time for this, but I am sure that I am not alone in this

    ​

    Congratulations to all of you who have continued here, your strength and perseverance are too much, keep fighting in pursuit of your dreams, only you know what you want and can achieve, do not give up, persist, together we go beyond, stay srtong warriors.

    submitted by /u/phabulu
    [link] [comments]

    UK man’s bank account frozen for 6 months and ongoing due to trading crypto

    Posted: 01 Feb 2019 02:48 PM PST

    Transaction Censored. "Maduro Abandons Plan To Ship 20 Tons Of Venezuelan Gold Abroad"

    Posted: 01 Feb 2019 06:39 PM PST

    Google and Facebook allows scam and Fraud websites and banned Cryptocurrency/ Bitcoin advertisements !!! Doesn’t make sense!

    Posted: 01 Feb 2019 05:43 PM PST

    When this post is 5 hrs old I will be LIVE hosting my new show, CoinSpice 'n Chill #3: ANOTHER Bitcoin Cash Fork? w/ BCH Dev Mark Lundeberg

    Posted: 01 Feb 2019 02:43 PM PST

    Bitcoin ABC's "parked blocks" feature allows minority hashrate attackers to cause a permanent chain split with high probability.

    Posted: 01 Feb 2019 03:54 PM PST

    BACKGROUND

    ------------------------------------------------------

    In November, Bitcoin ABC introduced "auto-finalization" and "parked blocks" functionality in order to mitigate the risk of 51% attacks.

    Roughly, the way auto-finalization works is that after receiving a new block, a node will look back ten blocks prior and mark that previous block as finalized, which means that the node will not reorg past that point without manual intervention. This prevents attackers from double spending with large reorgs, and thus provides some protection for exchanges and the like.

    The parked blocks functionality is intended to prevent against medium-length reorgs by adding a proof of work penalty. Specifically, a 4+ block reorg requires double the PoW; a 1 or 2 block reorg requires an extra 1/2 blocks' worth of PoW, and a 3 block reorg requires an extra blocks' worth of PoW. These are approximations, because of BCH's DAA which changes each block, but you can find this implemented in FindMostWorkChain() in validation.cpp.

    When these changes were added, there was some discussion on r/btc about how auto-finalization could lead to chain splits because an attacker could mine a 10 block secret chain and broadcast it right at the perfect time that the honest network has broadcast its 10th block from the fork point; however, this is a difficult attack to pull off, and the parked blocks functionality actually makes it such that the attacker would need to mine more like 20 blocks secretly (approximately, because of the DAA), which makes it nearly impossible.

    However, I did not see significant discussion regarding the implications of the parked block functionality itself, and the negative way in which it interacts with auto-finalization. Here is my attempt to rectify that, by presenting an attack that could cause chain splits with moderate probability even for attackers with minority hash rate.

    ​

    ATTACK:

    ----------------------------------------------------

    1) Somehow force a soft-split with the parked chain.

    2) Make sure that the soft split continues until both sides finalize a block on their side of the split (possibly via balancing hashpower on both sides of the soft split).

    More specifically:

    1) Mine 3 blocks before the honest network mines three blocks, and broadcast block 3 when you detect honest block 3 has been broadcast.

    2) Mine such that the difficulty/work condition is fulfilled (see step 2 below regarding lowering the difficulty): block1 + 1/2*priv2 + 1/2*pub2 > pub4 + priv4. If this condition isn't met, the attacker can just try to win the split from the next step and get 3-4 block rewards

    3) Ensure that each side of the soft split mines block 4 before the other side mines block 5, moving into the double-PoW penalty phase. This may require withholding blocks temporarily if "too far ahead", such that there is a 3vs3 split. Since this could happen, it improves our probability of success compared to the calculations below.

    4) Mine at the tip of whichever chain is behind, such that neither side reorgs before finalizing a block on their side of the split. That is, each side must mine 7 blocks w/o being reorg'd. (Must mine 1 before the other mines 4, or 2 before 8, etc.)

    --Analysis is for step 4 is complicated and thus omitted below, but this is likely to succeed, and extremely likely to succeed if the network is split close to evenly or if the attacker has substantial hash power.

    ​

    Analysis:

    ----------------------------------------------------------

    Let x = attacker hash rate; y = main chain hash rate after soft split; z = alt/"attack" chain hash rate after soft split.

    -----STEP 1-------------

    --Start by assuming the attacker has just mined a block and keeps it secret; then they must win 2 blocks before the honest chain wins 3

    --There are 6 possible ways to win: AA, AHA, HAA, AHHA, HHAA, HAHA (A = attacker block; H = honest block.)

    Pr[success] = x^2 + 2*x^2*(1-x) + 3*x^2*(1-x)^2

    x = 1/20 --> 1.4%

    x = 1/10 --> 5.23%

    x = 1/4 --> 26.17%

    x = 1/3 --> 40.74%

    x = 1/2 --> 68.75%

    x = 3/5 --> 82.08%

    ------STEP 2---------------

    Ideally, the 4th block for both chains will be of the proper difficulty that would prevent either chain from being reorged by seeing that 4th block, in which case the soft split should persist. This occurs if the following conditions are met:

    1) In order to prevent the 4th honest block from reorging our 3 private blocks, we need: privChainWork + 1/2*(privBlock1work + privBlock2work) > mainChainWork

    2) In order to prevent the 4th attack block from reorging the 3 public blocks, we need: mainChainWork + 1/2*(pubBlock1work + pubBlock2work) > privChainWork

    Note that pubBlock1work == privBlock1work in all cases. Some algebra:

    Condition 1 --> priv1 + priv2 + priv3 + 1/2*priv1 + 1/2*priv2 > pub1 + pub2 + pub3 + pub4

    Condition 2 --> pub1 + pub2 + pub3 + 1/2*pub1 + 1/2*pub2 > priv1 + priv2 + priv3 + priv4

    --> priv1 + priv2 + priv3 > pub1 + pub2 + pub3 + pub4 - (1/2*priv1 + 1/2*priv2)

    --> pub1 + pub2 + pub3 > priv1 + priv2 + priv3 + priv4 - (1/2*pub1 + 1/2*pub2)

    --> pub1 + pub2 + pub3 > pub1 + pub2 + pub3 + pub4 - (1/2*priv1 + 1/2*priv2) + priv4 - (1/2*pub1 + 1/2*pub2)

    --> 0 > pub4 + priv4 - (1/2*priv1 + 1/2*priv2) - (1/2*pub1 + 1/2*pub2)

    --> (1/2*priv1 + 1/2*priv2) + (1/2*pub1 + 1/2*pub2) > pub4 + priv4

    --> block1 + 1/2*priv2 + 1/2*pub2 > pub4 + priv4

    This is extremely likely if the difficulty is decreasing, which can happen on the private chain by mining blocks with future timestamps, and is likely on the main chain as well, since it will have less hashpower than before the fork point.

    ------STEP 3------------------------

    --What is the probability that both chains mine block 4 before the other mines block 5?

    --Assume both chains have 3 blocks already and the attacker has no secret blocks. If the attacker successfully mined block 4 already, our chances would be higher, so this is an underestimate.

    --The chance of success depends on how much hash is on each side, which we don't know. Here we analyze two possibilities:

    1) y = z (attacker's best case);

    2) y = 3z (1/4 of the honest hash is on one side, 3/4 on the other)

    --For case 1, assume the miner simply shuts off until one side wins a block, and then immediately mines the other side. They could also pick a side to start with, but we ignore that possibility. For case 2, we assume the attacker mines on the minority chain until a block is mined, and switches if the minority chain wins the first block.

    Case 1:

    Pr[success] = x + z = x + y

    x = 1/20 --> 52.5%

    x = 1/10 --> 55%

    x = 1/4 --> 62.5%

    x = 1/3 --> 66.67%

    x = 1/2 --> 75%

    x = 3/5 --> 80%

    Case 2:

    Pr[success] = (x+z)*(x+y) + y*(x+z) = x^2 + 2xy + 2yz + xz

    x = 1/20 --> 42.41%

    x = 1/10 --> 47.13%

    x = 1/4 --> 60.16%

    x = 1/3 --> 66.67%%

    x = 1/2 --> 78.13%

    x = 3/5 --> 84%

    -----END STEP 3---------------------

    ​

    ​

    EXAMPLE: Attacker has x fraction of the hash rate, and if he successfully finishes step 1, we assume that the difficulty works out in step 2 about half the time (probably a significant underestimate). Assume that each step is independent (not true, and causes an underestimate of success probability). Assume that the soft split that results splits the hash power 3 to 1, as in case 2 above. What is the probability of getting to the final step of the attack? How many initial blocks can the attacker expect to throw out before succeeding, and how long should this take given their hash rate?

    x = 1/20 --> 0.3% --> 334 blocks thrown out, 6680 blocks total, 46.4 days

    x = 1/10 --> 1.23% --> 82 blocks thrown out, 820 blocks total, 5.7 days

    x = 1/4 --> 7.87% --> 13 blocks thrown out, 52 blocks total, 8.7 hours

    x = 1/3 --> 13.58% --> 8 blocks thrown out, 24 blocks total, 4 hours

    x = 1/2 --> 26.86% --> 4 blocks thrown out, 8 blocks total, 1.3 hours

    x = 3/5 --> 34.47% --> 3 blocks thrown out, 5 blocks total, < 1 hour

    ​

    DISCUSSION

    -------------------------------------------

    There are tradeoffs between protecting against chain-split attacks and protecting against deep reorgs, and a chain like that of BCH, with minority SHA-256 hashrate, must tread carefully. However, I think I have demonstrated here that there isn't a tradeoff when you have both parked blocks AND auto-finalization - the security assumption of "everything is fine if majority hashrate is honest" is no longer true, because a 33% attacker can cause a far worse outcome than a deep reorg.

    That said, unlike with 51% attacks, this particular attack is one that isn't as likely to be profitable for the attacker financially, so it may not be exploited by random Internet bad guys. Also, it would require some more complicated software and is less likely to succeed without some amount of network intelligence, like knowing which nodes are miners or exchanges to target. However, it CAN still be profitable in a number of ways: shorting BCH, low-conf double spends, and/or the possible selfish mining profits that could accrue from a failure at some step of this strategy.

    Timejacking may be useful to smooth over some of the parts of the attack by making sure that a timejacked node will view a block as valid/invalid when the rest of the network doesn't, via timestamp manipulation. This can buy the attacker a little bit of time, and "shape" the network such that he knows which side of the split his targets may be on. Furthermore, if the attacker fails to split the network somewhat evenly, then he can ignore the minority side of the fork and immediately start trying again on the majority side, in an attempt to cause a 3-way split.

    Finally, while you may believe that this attack is improbable, the prevailing wisdom of this sub is that a super powerful cabal of bankers will stop at nothing to destroy Bitcoin Cash (operating via their alleged proxy, Blockstream), and since a well-resourced attacker should be able to pull this attack off, I believe y'all should be more concerned than you have been. My recommendation is to remove the parked block functionality from ABC entirely, and accept the risk of medium-length reorgs.

    submitted by /u/iwantfreebitcoin
    [link] [comments]

    Startup Launches Loaded Bitcoin Cash Notes to Spread BCH Adoption

    Posted: 01 Feb 2019 11:29 AM PST

    Cryptocapital.Co May Be Crypto's Black Swan

    Posted: 01 Feb 2019 01:02 PM PST

    Started streaming the family dog so that out of town relatives could see her, she's only accepting BCH for treats!

    Posted: 01 Feb 2019 09:39 AM PST

    Similar to BTC, BCH too gets physical notes

    Posted: 02 Feb 2019 02:00 AM PST
    Read more
    at

    No comments:

    Post a Comment