The Dagger (XDAG) cryptocurrency

Community site: https://xdag.io
The Main net was launched January 5, 2018 at 22:45 GMT

Principles:

Directed acyclic graph (DAG), not blockchain
Block = transaction = address
Original idea and implementation
Mineable, no premine, no ICO
Mining new money every 64 seconds

HOW-TO:

Docs:

Main chain idea:

Every block in DAG has up to 15 links to another blocks (inputs and outputs). Block B is referenced by another block A if we can reach B from A by following the links. Chain is a sequence of blocks each of which is referenced by the previous block. Chain is called distinct if every its block belongs to separate 64-seconds interval. _Difficulty_ofblock is 1/hash where hash is sha256(sha256(block)) regarded as little-endian number. _Difficulty_ofchain is sum of difficulties of blocks. _Mainchain is the distinct chain with maximum difficulty. Blocks in main chain are called _mainblocks.

Daggers are mined in every main block. There are three periods of mining:

Stage 1	Stage 2	Stage 3
Block #1 to #1,017,322	Block #1,017,323 to #2,097,151	Each 2,097,152 blocks
1024 XDAG each block	128 XDAG each block	64 * (1/2)^n XDAG each block

The maximum XDAG supply is approximately 1.446294144 billion.

Each dagger is equal to power(2,32) cheatoshino. Transaction is valid if it is referenced by a main block. Valid transactions are strictly ordered depending on main chain and links order. Double spending is prohibited because only first concurrent transaction (by this order) is applied.

Structure of block:

The on-disk format will change in the future. Consider this the network protocol. Each block has a fixed size of 512 bytes. Block consists of 16 fields each of which has length 32 bytes. Field 0 is header, it consists of 4 quadwords:

transport-layer header
types of all 16 fields, 4 bits for one type
timestamp of the block, in seconds from Unix era * 1024
block fee in cheatoshi

Types of fields:

nonce
header
transaction input: 24 lower bytes of block hash and 8 bytes of input amount
transaction output, structure is the same as input
half of block signature; ECDSA number r or s; digest for signature is hash of (block concate public key)
half of output signature; only owner of this key can use this block as input
public key (x) with even y
public key with odd y
header of testnet
... 15. are reserved for future usage.

Transport layer:

The dnet network is used as transport layer. A new transport layer will come in the future.

Maintainers:

Evgeniy ( XDAG: gKNRtSL1pUaTpzMuPMznKw49ILtP6qX3, BTC: 1Jonano4esJzZvqNtUY6NwfPme3EMpVs7n )
Frozen ( XDAG: ~~+L5dzSh1QZv1We3wi8Of31M8eHwQJq4K~~ )

Code Contributors:

Full list of contributors including all contributors for XDAG sub-projects.

XDagger / xdag

readme