Sorry for the slow reply.

The sigma, ch, and ma are defined at the bottom of my first post here:

ch(E,F,G) is (E∧F)⊕(⌐E∧G)
ma(A,B,C) is (A∧B)⊕(A∧C)⊕(B∧C)
Σ0(A) is (A>>>2) ⊕ (A>>>13) ⊕ (A>>>25)
Σ1(E) is (E>>>6) ⊕ (E>>>11) ⊕ (E>>>25)

They are just fairly complex functions of some of the subblocks (for example you calculate ch by taking blocks E,F, and G and using them in the formula (E∧F)⊕(⌐E∧G). The ∧ is AND taken one bit at a time (so separate bits do not affect each other), the ⌐ is not taken one bit at a time (flip all bits, basically), and ⊕ is XOR, bit by bit, as I described it at the top of my post.

That being said, I'm extremely happy that someone around my age is interested in this, and is managing to go into such depth.

Your profile says your location is in the Netherlands...

Can you sign a message with that address?

I would use most toward helping fund education where current systems are corrupt or ineffective, but would use some on upgrading my current computer setup.

Most operations in SHA-256 are bitwise operations--xor, rotation, etc. I'll be referencing Wikipedia in my descriptions.

In a rotation, all bits are shifted around a certain number of spaces. For example, rotating
right 3 bits yields

where a,b,c,d,e,f,g,h,i,j are bits. Basically, each bit is moved over some spaces, and bits on the end are moved around to the beginning after being "shifted off".

The ">>>" symbols used in crypto to describe Σ-zero and Σ-one steps of SHA are these rotations exactly.

Simiarly, bitwise operations such as XOR exist. They handle each bit separately using the following tables:


For example, (E∧F)⊕(⌐E∧G) means:

(E AND F) XOR ((NOT E) AND G)

which means to take NOT E, AND it with G, and then XOR that with the result of ANDing E and F.

Addition modulo 2^32, shown as red boxes on the diagram on Wikipedia, means that the two inputs are added (carrying as with regular addition), just in binary. If the result overflows 32 bits, then we ignore the overflow. For example:


While usually the leftmost 1 in the carry (marked with a *) would be brought down, it is considered overflow in this case and ignored, since it falls as the 33rd digit. Only 32 bits are retained, since the compression function works with 32-bit-length data. Our result is thus 10001111100100011101110001011001 and not 110001111100100011101110001011001.

As a summary, SHA-2 (SHA256 being a member of the SHA-2 family) compresses a 256-bit length of data by first splitting it into 8 blocks, and then performing the following operations (where A-H are input blocks and A' through H' are output blocks):

A'= W(t)+K(t)+H+ch(E,F,G)+Σ1(E)+ma(A,B,C)+Σ0(A)
B' = A
C' = B
D' = C
E' = W(t)+K(t)+H+ch(E,F,G)+Σ1(E)+D
F' = E
G' = F
H' = G

ch(E,F,G) is (E∧F)⊕(⌐E∧G)
ma(A,B,C) is (A∧B)⊕(A∧C)⊕(B∧C)
Σ0(A) is (A>>>2) ⊕ (A>>>13) ⊕ (A>>>25)
Σ1(E) is (E>>>6) ⊕ (E>>>11) ⊕ (E>>>25)

Hopefully this makes sense. If not, feel free to ask and I'll try to clarify.

Generally, unless you can reach an agreement with one like UPS or FedEx to have rates auto-calculated and mailing slips printed for senders, it would be more workable for senders to specify shipping rates, pay for shipping themselves, and submit at least a tracking number to the site. You can also place responsibility more squarely on the sender for not shipping.

How can we be sure you won't scam us? Is escrow accepted?

Followed by over 14000 people on Facebook. Quite suspicious at best.

I have a home machine behind a NAT I can spare at least some of the time (although it is on a dynamic IP, and not guaranteed up 24/7). I am willing to run a python script after inspecting it for security flaws, have it log results to a file somewhere, and then send you the contents of that log.

Can someone with Pascal knowledge audit this please?

I would be interested but I personally do not use Skype. PM here or email would be acceptable for me. Is that OK with you?

This server's operator is not stealing your bitcoins, to the best of my knowledge, and filing complaints will either end up with nothing happening, or an innocent bitcoin relay node being taken off the net. The "relayed by" field on a blockexplorer shows what node the blockexplorer heard of the transaction from. It is very unlikely that it originated there.

If I am understanding the situation correctly, your demanding that 5.9.24.81 be taken down by their host is doing a disservice to the community, by helping set a bad precedent of relaying nodes being responsible for txns they relay, and by taking down a highly-connected bitcoind node.

Exactly, waiting for the transfer from Coinbase to clear would be far better.

In most cases it's hard, even sometimes for higher ranks.

Do you have collateral you can put up?

All txns have confirmed at this point.

In that case, you're really not understanding the basics here. If you actually saved the file as /root/node.py there would be no such issues. Use the actual location of the file.

Your fault for using such exchanges. I use Coinbase without a problem.

Just because you fell for a scam site doesn't justify your calling the currency a scam. Let's say I bought bonds that turned to junk, using dollars. Does that make dollars a scam?

How much are you willing to pay in BTC? What features do you need?

No, no, no, don't use a random web-wallet. Use something like blockchain.info and make sure to back up the wallet and identifier to email.

To OP: Make sure you have a backup. Asking on the forum isn't going to undo your loss as we do not have the power to undelete your files, or to restore your bitcoin.

Try