In a debit system, you gather your money up front and then spend it. In a credit system, you spend the money first and pay the bill later. Checks, charge accounts, and credit cards are credit systems. Just as cash and credit coexist in today's business climate, both exist in the digital world as well. Although users can make digital copies of such notes, a bank redeems each note number only once.
Digital credit is similar to the credit systems used in the business world.
The main difference lies in the i ncorporation of digital time stamps and signatures that build auditability and accountability into the system and replace the paper trail that's no longer there. With such a system, the payer creates a voucher record that contains a description of the transaction, the names of the payer and the recipient, the date and time of the transaction, and the amount to be paid. The payer signs this voucher with his or her private key. Using a public key, the recipient of a voucher can read the record and verify that it was signed and obliged by the possessor of that private key. The recipient can then submit the voucher to a clearing system and have legal grounds for collecting payment.