Author

Topic: Why do Bitcoin addresses start with a "1"? (Read 1349 times)

legendary
Activity: 3472
Merit: 4801
January 13, 2015, 04:12:20 PM
#12
Lol how the hell do you guys remember all this stuff ?

Remember what stuff?
newbie
Activity: 4
Merit: 0
January 13, 2015, 03:51:16 PM
#11
Lol how the hell do you guys remember all this stuff ?
hero member
Activity: 728
Merit: 501
January 13, 2015, 10:46:06 AM
#10
By looking the combination address , I think it need a very long time.

But is there any chance that someday bitcoin address will run out of address ?



The identifying part of a bitcoin address is a 160-bit hash, 160 bits gives in the range of 10^48 addresses, or roughly 1 for every atom on the planet
legendary
Activity: 3472
Merit: 4801
January 13, 2015, 09:00:24 AM
#9
is there any chance that someday bitcoin address will run out of address ?

No.
legendary
Activity: 1862
Merit: 1015
January 13, 2015, 08:58:44 AM
#8
By looking the combination address , I think it need a very long time.

But is there any chance that someday bitcoin address will run out of address ?

copper member
Activity: 1498
Merit: 1528
No I dont escrow anymore.
January 13, 2015, 03:32:09 AM
#7
Ummm, im not really sure what all of these technical terms are...

From what I understand, its because thats the version number?

tl;dr yes, but only for the "usual" addresses (pay 2 pubkeyhash)
legendary
Activity: 1092
Merit: 1000
nahtnam.com
January 13, 2015, 12:39:17 AM
#6
Ummm, im not really sure what all of these technical terms are...

From what I understand, its because thats the version number?
hero member
Activity: 728
Merit: 501
January 12, 2015, 10:07:34 AM
#5
If an address begin with "1" then it's a hash of a public key, "3" for a script hash, "5" for a private uncompressed key, etc

https://en.bitcoin.it/wiki/List_of_address_prefixes
legendary
Activity: 1526
Merit: 1000
the grandpa of cryptos
January 12, 2015, 01:55:12 AM
#4
because it was 1st crypto!
legendary
Activity: 3472
Merit: 4801
January 12, 2015, 01:48:10 AM
#3
Hey!

I was just wondering why all bitcoin addresses start with a "1".

Thanks.

They don't ALL start with a 1.

Pay-to-ScriptHash addresses (commonly used for multi-sig) start with a 3.

Bitcoin Addresses have three parts.

The first part is a one byte "version" that indicates what type of output script the address represents.  The most commonly used output script (Pay-to-PubKeyHash) uses a "version" of 0x00

The second part is the hash.  In the case of a Pay-to-ScriptHash address, this would be the 20 byte hash of the script.  In the more common Pay-to_PubKeyHash address, this would be a 20 byte hash of the ECDSA public key.

The last part is a 4 byte checksum calculated as the first 4 bytes of a 32 byte SHA-256 hash.  This is used to verify that there weren't any typing errors when entering the bitcoin address and prevents accidentally sending to a mis-typed address.

Once all 25 bytes are concatenated together, the resulting value is converted to base58 using the following value representations:

ValueCharacterValueCharacterValueCharacterValueCharacter
01122334
45566778
899A10B11C
12D13E14F15G
16H17J18K19L
20M21N22P23Q
24R25S26T27U
28V29W30X31Y
32Z33a34b35c
36d37e38f39g
40h41i42j43k
44m45n46o47p
48q49r50s51t
52u53v54w55x
56y57z

The leading character '1', which has a value of zero in base58, is reserved for representing an entire leading zero byte, as when it is in a leading position, has no value as a base-58 symbol. There can be one or more leading '1's when necessary to represent one or more leading zero bytes.
copper member
Activity: 1498
Merit: 1528
No I dont escrow anymore.
January 12, 2015, 01:46:53 AM
#2
Because at a certain step durring address generation a "version byte" is added in front of the hash. IIRC its
VersionByte + RIPEMD-160(sha256(PubKey). Thus at this stage the address starts with 00 (in hex) for the main bitcoin network. Then there is the checksum which is the first 4 bytes of sha256(sha256(VersionByte+RIPEMD-160(sha256(PubKey)))) that gets attached to the end. This does not influence the beginning however, thus we still have 00 (still in hex). The last step is the Base58 encoding, which has no zero. Thus the first value is a 1 and the 00 get converted to 1something.
legendary
Activity: 1092
Merit: 1000
nahtnam.com
January 12, 2015, 12:49:27 AM
#1
Hey!

I was just wondering why all bitcoin addresses start with a "1".

Thanks.
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