From what I can tell, the Ethereum blockchain just stores accounts and balances – why did the original Bitcoin developers choose the method of storing all transactions for validation instead of just account balances? It seems like that would reduce blockchain size on disk quite a bit…
I was wondering what new cryptocurrency features may be introduced.
How can I find published new cryptocurrency features?
How is OP_RETURN used and why was it introduced in the first place?
On blockchain’s blockchain api documentation, located here
https://blockchain.info/api/blockchain_api
There is an api call that uses a parameter called block_index. What is this value, and how does it differ from block_height? From playing around with changing the block_index value in the following api call:
https://blockchain.info/block-index/$block_index?format=json
It seems like (imo quite arbitrarily, which adds to my confusion) that block_index 14849 corresponds to the genesis block. Finally, on the api page listed at the top the first example output they show gives a block whose index is 818044, yet when I enter the following api call into my browser’s address bar:
https://blockchain.info/block-index/818044?format=json
I get “Block Not Found”. Is this just a bug in blockchain.info that the example output they provide doesn’t actually work, or am I using block_index incorrectly?
I want to generate, say 100000 key pairs (address/private key). It should be done offline, without using websites/javascript , with a program on the command line. Of course, the software should use the best way to generate randomness. There is such function on https://www.bitaddress.org , but it’s javascript and is not easy to be used by scripts on the command line. Do you know of such software?
I realized a few days back, that if I send some bitcoins to someone, then it shows in blockchain an extra amount sent to my own wallet. So if I send 0.5 BTC from wallet A to B then blockchain shows
A--> B 0.5
A-->A 1 (basically sending it to my wallet as well.)
Today I noticed a different wallet address during a transaction. So it was like
A--> B 0.2
A--> C 0.5
Checking address C on blockchain, it gets sent back to A in some time. But since this morning, the bitcoins haven’t come back to A. If I open my wallet on multibit, it shows the correct balance. However on blockchain, it’s 0.5 less. The funds from C have not been sent back to A, but it shows on multibit the right balance in A.
Given a private key, I can get the uncompressed or compressed version of the public key like so.
EC_KEY* pKey = EC_KEY_new_by_curve_name(NID_secp256k1);
std::vector<unsigned char> getPubKey(EC_KEY* pKey, bool compressed) const {
if (compressed)
EC_KEY_set_conv_form(pKey, POINT_CONVERSION_COMPRESSED);
else
EC_KEY_set_conv_form(pKey, POINT_CONVERSION_UNCOMPRESSED);
int nSize = i2o_ECPublicKey(pKey, NULL);
std::vector<unsigned char> pubKey(nSize, 0)
unsigned char* pBegin = &pubKey[0];
i2o_ECPublicKey(pKey, &pBegin)
return pubKey;
}
But how can I get the uncompressed public key from the compressed public key without knowing the private key?