Luhn algorithm

The Luhn algorithm or Luhn formula, also known as the "modulus 10" or "mod 10" algorithm, is a simple checksum formula used to validate a variety of identification numbers, such as credit card numbers, IMEI numbers, National Provider Identifier numbers in the US, and Canadian Social Insurance Numbers. It was created by IBM scientist Hans Peter Luhn and described in U.S. Patent No. 2,950,048, filed on January 6, 1954, and granted on August 23, 1960.

The algorithm is in the public domain and is in wide use today. It is specified in ISO/IEC 7812-1. It is not intended to be a cryptographically secure hash function; it was designed to protect against accidental errors, not malicious attacks. Most credit cards and many government identification numbers use the algorithm as a simple method of distinguishing valid numbers from mistyped or otherwise incorrect numbers.

Description

The formula verifies a number against its included check digit, which is usually appended to a partial account number to generate the full account number. This number must pass the following test:

Good Good

"Good Good" is the fourth and final single from Ashanti's album The Declaration.

Song information

The accompanying video featured a cameo by Nelly. It premiered on July 17, 2008 on Yahoo!. The song contains samples of "Bennie and the Jets" by Elton John and "The Girl is Mine" from Michael Jackson.

On their 2009 collaboration album, We Are Young Money, Lead rapper Lil Wayne and his group says the line of "She got that good good" on the song "BedRock" which features Ashanti's former label mate R&B singer Lloyd.

Critical reception

Many album reviews named 'Good Good' a good single choice pick.

Music video

The music video was premiered in Yahoo Music and BET on July 17, 2008. It was directed by Melina Matsoukas . The video features an appearance by the rapper Nelly playing Ashanti's husband in the video. Ashanti described the video as "reality vs. fantasy vs. pin up. It's basically just saying that to keep your man, you know, you got the good-good, you look sexy, and you're still cleaning the house with your high-heels and your shades and your diamonds! (Laughs)"

Credit card

A credit card is a payment card issued to users (cardholders) as a method of payment. It allows the cardholder to pay for goods and services based on the holder's promise to pay for them. The issuer of the card (usually a bank) creates a revolving account and grants a line of credit to the cardholder, from which the cardholder can borrow money for payment to a merchant or as a cash advance.

A credit card is different from a charge card, where it requires the balance to be repaid in full each month. In contrast, credit cards allow the consumers a continuing balance of debt, subject to interest being charged. A credit card also differs from a cash card, which can be used like currency by the owner of the card. A credit card differs from a charge card also in that a credit card typically involves a third-party entity that pays the seller and is reimbursed by the buyer, whereas a charge card simply defers payment by the buyer until a later date.