A secure wireless LAN device includes a housing, a wireless transceiver carried by the housing, and a cryptography circuit carried by the housing. The cryptography circuit may operate using cryptography information and may also render unuseable the cryptography information based upon tampering. The cryptography circuit may include at least one volatile memory for storing the cryptography information, and a battery for maintaining the cryptography information in the at least one volatile memory. Accordingly, the cryptography circuit may further include at least one switch operatively connected to the housing for disconnecting the battery from the at least one volatile memory so that the cryptography information therein is lost based upon breach of the housing. The cryptographic information may comprise a cryptography key and/or at least a portion of a cryptography algorithm. This cryptographic information remains relatively secure and is lost upon tampering, such as removing the housing.