# Can someone explain to me how do you read the blockchain.info transaction data?

Ok so i've been using bitcoin for some time now, but i never figured out how to read the blockchain.info transaction data. Here's a sample of what I mean:

Here are a few questions that i have:

1. Are those bitcoin wallet addresses on the left and right column?
2. What is the top address representing that starts with a 7 and every other address starts with a 1? Whats the difference?
3. Can someone explain exactly whats going on here? I see 5 addresses that are pointing to the many other addresses on the right column.
4. On the bottom it seems like it's a total of \$1453, but if you add up all those addresses it clearly doesn't equal that.

## 4 Answers

I am new in this area, but it seems the transaction id at the top is a hash in hex. The addresses that specify input and output of funds are encrypted information and so include alphabet other than a,b,c,d,e,f. This should be the main diffrence between top title figure and transaction figures and not the starting digits.

1. Bitcoin addresses on the left are valid addresses from wallet, someone has private key for them. Bitcoin addresses on the right can be any addresses, even addresses, that nobody has private keys for them (so bitcoins on them are unspendable).
2. This is transaction id.
3. Bitcoin transaction can have many addresses on the left and on the right. Bitcoins are moved from left addresses to right.
4. You opened a page with specific address. \$1453 means, that this address received \$1453 with this transcation. If you open a page with this transaction directrly https://blockchain.info/tx/7dd8efe094e11c890eea7dc65e9bc7fb44903ed3e9b856e854d7d31e247ea1f2 you can see total sum. If you sum up left part and substract sum of right part, you can calculate fee.
• but why wouldn't the right side just be 1 address? I can understand when sending bitcoin from your wallet it can come from multiple addresses, but why would it go into many different ones? it should just be just the one your sending to. – Patoshi パトシ Jan 23 '14 at 17:21
• You're wrong that nobody has the private keys for the right-hand addresses. Somebody does, just not the sender. If nobody had the private keys for the right hand addresses, this would be like flushing \$88,117 down the drain. – ChrisW Jan 24 '14 at 1:43
• duckx, transactions do not work in a such way. There are no addresses with balances under the hood. It is high level abstraction. Each transaction has input and output. You are working only with them. For example: you receivce 2 BTC to addr1 (with single transaction). Now you want to send me 0.5 BTC. You must create transaction, that use output of 2 BTC as input, and has 2 outputs: 0.5 BTC for me, and 1.5 BTC - to you (as remainder). It can be the same address, or any other address from your wallet. Bitcoin-qt uses new address. Look at bitcoin wiki for details about how transactions work. – Zergatul Jan 24 '14 at 10:51
• ChrisW, I described this case as a special case. Of course, in the most cases someone has private key. – Zergatul Jan 24 '14 at 10:53

I agree with most of what @Zergatul said, except for the part about no-one having the private keys for the right-hand addresses.

This is a classic "SendMany" type of transaction. From an account in a wallet, a user wants to send about \$88,000 in BTC to many different people. I often see this type of transaction with mining pools who are paying out shares to individual miners, but there are many other possible explanations.

In this case, because the sender collected 5 unspent inputs to create the amount of BTC that he/she needed. That's the left hand column. The wallet generally does this automatically when creating a transaction.

Then the sender specified the different recipients and the amount that should be directed to each. Those are the right-had addresses. The Bitcoin protocol puts all of these recipients in a single transaction.

The transaction you are looking at is transaction 7dd8efe094e11c890eea7dc65e9bc7fb44903ed3e9b856e854d7d31e247ea1f2. This string is the hex encoded SHA256 hash of the transaction itself and serves as a unique identifier (each transaction has its unique hash).

The left column lists the input addresses from which the bitcoins where claimed, i.e., the "sending" addresses. An address is a base58 encoded string, comprising the network identifier (1 for Bitcoin Mainnet), the 20 byte hash of the public key and a 4 byte checksum. As you can see the address 1AqTMY7kmHZxBuLUR5wJjPFUvqGs23sesr shows up twice because we reference a specific output to be spent. That address has received some coins in two different transactions and now we merge them into this transaction. Next to each input is the value it contributed to the transaction and a link to the output being spent.

On the right side you have similar information for the outputs this transaction creates: a destination address and the amount of coins that are destined to that address.

So this transaction claims coins from 5 outputs (for a total of 109.32071408 BTC) on the left and redistributes the coins to the new outputs on the right (also totalling 109.32071408 BTC). Each output is associated with an address and a value.

Since the sum of inputs minus the sum of outputs is 0, there is no fee attached to this transaction.

Finally the \$1453 is the dollar value of the outputs destined for the address page you were looking at at the time. This number is how many bitcoins were transferred to/from this address (1AqTMY7kmHZxBuLUR5wJjPFUvqGs23sesr) as part of this transaction.