How do you derive the lambda and beta values for endomorphism on the secp256k1 curve?

You can see a little background about this on this bitcointalk post by the late Hal Finney.

Beta and lambda are the values on the secp256k1 curve where:

λ^3 (mod N) = 1

β^3 (mod P) = 1

As seen here, in hex, N and P are:



The actual values of lambda and beta are easily verifiable and are:

λ = 5363ad4cc05c30e0a5261c028812645a122e22ea20816678df02967c1b23bd72

β = 7ae96a2b657c07106e64479eac3434e99cf0497512f58995c1396c28719501ee

The question for me is, how do you derive this? Can someone show me step-by-step how you can figure out these values?

Also posted to the Cryptography Stack Exchange

Where is the Mycelium wallet file stored?

I have a fairly straightforward question that’s still unanswered after googling for days for a definite answer, I hope you guys can help me out with this one here.

Background: I have Mycelium Bitcoin Wallet installed on my Android phone [ROOT], I have backed up my HD wallet which also contains Local Trader account, and have been successful in restoring said backup[s] (by means of un-installing app, wiping it’s old data and re-installing / loading wallet from backup (Master seed)). I also have redundant backups of the app and it’s data (I assume that includes the wallet file?) made with Titanium Backup.

Question: I however still do not know where Mycelium’s wallet resides, is it on my SD extCard? SD Card? Data partition? Protected Storage? Is it just determined by the Master Seed and hence resides nowhere?

Final Note: I’m eagerly awaiting this piece of information to be at ease with my policies, knowing that I can manually backup/encrypt my wallet file (if there is one) is really important to me.

Thanks in advance!

json_rpc_call solo mining with bitcoin running on Windows 7 for antminer

I setup BitcoinD on a Windows 7 PC. I configured for defaults except user/pw and rpcallowip= have also tried 192.168.1.* with no luck.

I ultimately want to use an Antminer to connect to it for solo mining but cannot use it for anything other than mining on the same computer on which it is running.

WORKING: using bfgminer with the following command line:
bfgminer-5.0.0-win64\bfgminer-5.0.0-win64\bfgminer.exe -o -u rpcuser -p rpcpw

NOT WORKING: using bfgminer-5.0.0-win64\bfgminer-5.0.0-win64\bfgminer.exe -o -u rpcuser -p rpcpw

The only difference is the IP address where 123 is my IP.

Error: “json_rpc_call failed, retry after 30 seconds”

I looked at firewall and it has entries for “Bitcoin Core”

“Netstat -a” output:

Antminer says pool is dead.

How do I get another computer or antminer, on my network, to connect for solo mining?


Where can I find code that allows me to calculate Z1 and Z2 from an ECDSA signature?

By following Recovering Bitcoin private keys using weak signatures from the blockchain, I am able to do other calculations, but I have no idea how to calculate Z1 or Z2. There was a public code available by Sean Bradley:

But it does not seems to work now. Is there some other public code to calculate Z1 and Z2 in any language. I can convert it to the language of my preference. Any help is appreciated.

How are change addresses treated differently by Bitcoin Core?

I understand the reasons for wanting to use new change address for each transaction, but am unsure as to how they are treated by the Bitcoin core client.

  1. Is the address deleted as soon as the funds it received as change are spent?
  2. The client probably doesn’t watch for any further sends to these addresses, right?

Ripple: only a sub-network reaching a consensus is largely enough to be decentralized&secure system? [closed]

I spent a while reading ripple protocol, specially the consensus process,
the protocol works based only on a sub-network ( from a huge network) reaching a consensus for the current state, it’s supposed to prevent double-spending and other attacks. There is no analysis about fork events!

First, any one can explain step by step the underlying consensus mechanism?
Second, what’s in the mechanism that prevents double-spending, attacks and fork events?

Is it chain of headers rather than a chain of blocks?

We know widely used explanation of the blockchain:
Every block contains a hash of the previous block“. The sentence above implies that since every block contains a hash of the previous block, therefore every block should have a knowledge about transactions included into the previous block because every block has a following structure:


  1. Magic No
  2. Block Size
  3. Block Header
  4. Transaction counter
  5. Transactions

Block Header:

  1. Version
  2. hashPrevBlock
  3. hashMerkleRoot
  4. Time
  5. Bits
  6. Nonce

However, every block does not have knowledge about transactions incuded into previous block correct???

As fas as I understand there are two chains in the Bitcoin:

  1. a chain of blocks headers (a block chain)
  2. a chain of transactions (Prev Tx Hash)

Hence just to clarify, rather than saying: “every block contains a hash of the previous block”, would not it be correct to say: “header of every block contains a hash of header of the previous block”?

Please correct my assumptions if I am wrong. Thanks.