Block chain

Block chain may refer to:

Block chain (database)

A block chain or blockchain is a permissionless distributed database based on the bitcoin protocol that maintains a continuously growing list of data records hardened against tampering and revision, even by its operators. The initial and most widely known application of block chain technology is the public ledger of transactions for bitcoin, which has been the inspiration for similar implementations often known as altchains.

Etymology

The block chain consists of blocks that hold timestamped batches of recent valid transactions. Each block includes the hash of the prior block, linking the blocks together. The linked blocks form a chain, with each additional block reinforcing those before it, thus giving the database type its name.

Model

A block chain implementation consists of two kinds of records: transactions and blocks.

Transactions

Transactions are the content to be stored in the block chain.Transactions are created by participants using the system. In the case of cryptocurrencies, a transaction is created anytime a bitcoin owner sends cryptocurrency to another.

Organic food

Organic foods are foods produced by organic farming. While the standards differ worldwide, organic farming in general features cultural, biological, and mechanical practices that foster cycling of resources, promote ecological balance, and conserve biodiversity. Synthetic pesticides and chemical fertilizers are not allowed, although certain approved pesticides may be used. In general, organic foods are also not processed using irradiation, industrial solvents, or synthetic food additives.

Currently, the European Union, the United States, Canada, Mexico, Japan and many other countries require producers to obtain special certification in order to market food as organic within their borders. In the context of these regulations, organic food is food produced in a way that complies with organic standards set by national governments and international organizations. Although the produce of kitchen gardens may be organic, selling food with the organic label is regulated by governmental food safety authorities, such as the US Department of Agriculture (USDA) or European Commission.