What are private keys?

[M3t]

I just got bitcoin-qt client today, and all that show up are public keys that people can send money to me.

What are private keys I hear so much about such as blockchain.info etc?

[1715088205]

1715088205

[1715088205]

1715088205

[1715088205]

1715088205

[Stephen Gornick]

I just got bitcoin-qt client today, and all that show up are public keys that people can send money to me.

The Bitcoin-Qt client takes care of everything so that a user doesn't need to know what a private key even is.   The keys are stored in the wallet.dat.

If you do want to see them, you can export them:
 - http://computriks.com/en/bitcoin-export-private-key

Or if you just want to see what one looks like:
 - http://www.BitAddress.org

[oakpacific]

And a reminder: no one but yourself should see your private keys.

[TiagoTiago]

The private keys are what is used to sign a transaction from one of your addresses. Basicly it is proof that the owner of that address said the money from that address should go somewhere else. And public keys are used to check if the signature really is from who it says it is.

As their name suggest, private keys are meant to be private (no one but the owner should have access to them in any form), and public keys are meant to be presented to the public. Though as already mentioned above the client automates the whole process so that the average user doesn't need to deal with the inner mechanics of the system.

[M3t]

Okay, can you give me an example of a transaction, break it down slowly >.<

I'm slow.

[TiagoTiago]

Okay, can you give me an example of a transaction, break it down slowly >.<

I'm slow.

In this context "transaction" is just a fancy way of saying "a record of money changing hands".

[virtualmaster]

The private key is a kind of brain wallet if you can remember it.

[wonderbash]

A transaction is group of data that is broadcast to the network and recorded into blocks. It stores the information of some bitcoins flowing from one address to another new public key (address).

[Stephen Gornick]

Okay, can you give me an example of a transaction, break it down slowly >.<

Here's what the data for one looks like:

Code:

Input:
Previous tx: f5d8ee39a430901c91a5917b9f2dc19d6d1a0e9cea205b009ca73dd04470b9a6
Index: 0
scriptSig: 304502206e21798a42fae0e854281abd38bacd1aeed3ee3738d9e1446618c4571d10
90db022100e2ac980643b0b82c0e88ffdfec6b64e3e6ba35e7ba5fdd7d5d6cc8d25c6b241501

Output:
Value: 5000000000
scriptPubKey: OP_DUP OP_HASH160 404371705fa9bd789a2fcd52d2c580b65d35549d
OP_EQUALVERIFY OP_CHECKSIG

 - http://en.bitcoin.it/wiki/Transaction#Principle_example_of_a_Bitcoin_transaction_with_1_input_and_1_output_only

And here's what one looks like in a nice viewer:

 - http://blockchain.info/tx/74aa359a7f007ec120bb0fbbb747797e1ded08bdcffeddce4e5ede5b1a40be5a?show_adv=true
(at the bottom click Advanced to see the link to get to the UTXO for the INPUT transactions)