A field programmable gate array (70) has security configuration features
to prevent monitoring of the configuration data for the field
programmable gate array. The configuration data is encrypted by a
security circuit (64) of the field programmable gate array using a
security key (62). This encrypted configuration data is stored in an
external nonvolatile memory (32). To configure the field programmable
gate array, the encrypted configuration data is decrypted by the security
circuit (64) of the field programmable gate array using the security key
stored in the field programmable gate array.