Data integrity

1. [The] condition that exists when data is unchanged from its source and has not been accidentally or maliciously modified, altered, or destroyed.

2. The condition in which data are identically maintained during any operation, such as transfer, storage, and retrieval.

3. The preservation of data for their intended use.

4. Relative to specified operations, the a priori expectation of data quality.

Source: from Federal Standard 1037C and from MIL-STD-188 and from the National Information Systems Security Glossary