Procedimiento empleado por sistemas financieros para disociar identificadores de la transacción referenciada. De esta forma, los robs de información proporcionan escasa información al atacante, pero el propietario auténtico puede establecer la relación debida con la transacción correspondiente.

Tokenization is the process of substituting a sensitive data element with an "easily" reversible benign substitute. Easily means with regards to the data owner - the algorithm used shouldn't be easy to guess and is the key security strength indicator of tokenization. Tokenization can be used to safeguard sensitive data involving, for example, bank accounts, financial statements, medical records, criminal records, driver's licenses, loan applications, stock trades, voter registrations, and other types of personally identifiable information (PII).

http://en.wikipedia.org/wiki/Tokenization_%28data_security%29

Tokenization is a process by which the primary account number (PAN) is replaced with a surrogate value called a “token”. De-tokenization is the reverse process of redeeming a token for its associated PAN value. The security of an individual token relies predominantly on the infeasibility of determining the original PAN knowing only the surrogate value.

PCI Data Security Standard (PCI DSS) -- Information Supplement: PCI DSS Tokenization Guidelines

Tokenization is the process of replacing sensitive data with unique identification symbols that retain all the essential information about the data without compromising its security. Tokenization seeks to minimize the amount of data a business needs to keep on hand.

http://searchsecurity.techtarget.com/