Each individual has an eleven-digit figure number which is printed on a blue plastic card. The last two numbers are the result of an arithmetic operation on the nine previous ones (which means that any typing mistake will result in an invalid number). The card is not always necessary is the number is memorized. The card is necessary for big purchases and verifying identity. The Federal Revenue has recently issued the "e-CPF", an electronic document that can be used as a nationwide, public-provided cryptographed signature key.
To register for a CPF in Brazil, an individual will need to provide a passport and proof of address (utilities bill). To get the forms necessary, go to www.receita.fazenda.gov.br/Principal/Ingles/Cpf/default.htm.
Registration is possible at a Post Office, branch of Banco do Brasil, branch of the Caixa Econômica Federal or at a Poupatempo office (citizen service center).