A method comprising: receiving at a first wireless routing node (108a-108e, 112) a digital signature of a trust authority, wherein the digital signature is generated by the trust authority using a Medium Access Control "MAC" address of the first wireless routing node and a public key of the first wireless routing node, wherein the digital signature is received from the trust authority via an isolated connection prior to the first wireless routing node joining a wireless network, and wherein the trust authority is associated with an industrial control and automation system; verifying at the first wireless routing node whether a digital certificate provided by a second wireless routing node (108a-108e, 112) in the wireless network is signed using the digital signature of the trust authority; based upon the verification, exchanging encryption keys with the second wireless routing node, the exchanged encryption keys including a first encryption key; receiving first data at the first wireless routing node from the second wireless routing node, wherein the first data is encrypted and is associated with the industrial control and automation system; decrypting the received first data using the first encryption key to produce first decrypted data, the first encryption key uniquely associated with communications between the first and second wireless routing nodes; encrypting the first decrypted data using a second encryption key to produce first encrypted data, the second encryption key uniquely associated with communications between the first wireless routing node and a third wireless routing node (108a-108e, 112) in the wireless network, the second encryption key being exchanged after the third wireless routing node has been verified by the first wireless routing node using the digital signature of the trust authority; communicating the first encrypted data to the third wireless routing node; and engaging in broadcast or multicast communications at the first wireless routing node using a network-wide encryption key distributed by the trust authority to each wireless routing node using a unique link. receiving at a first wireless routing node (108a-108e, 112) a digital signature of a trust authority, wherein the digital signature is generated by the trust authority using a Medium Access Control "MAC" address of the first wireless routing node and a public key of the first wireless routing node, wherein the digital signature is received from the trust authority via an isolated connection prior to the first wireless routing node joining a wireless network, and wherein the trust authority is associated with an industrial control and automation system; verifying at the first wireless routing node whether a digital certificate provided by a second wireless routing node (108a-108e, 112) in the wireless network is signed using the digital signature of the trust authority; based upon the verification, exchanging encryption keys with the second wireless routing node, the exchanged encryption keys including a first encryption key; receiving first data at the first wireless routing node from the second wireless routing node, wherein the first data is encrypted and is associated with the industrial control and automation system; decrypting the received first data using the first encryption key to produce first decrypted data, the first encryption key uniquely associated with communications between the first and second wireless routing nodes; encrypting the first decrypted data using a second encryption key to produce first encrypted data, the second encryption key uniquely associated with communications between the first wireless routing node and a third wireless routing node (108a-108e, 112) in the wireless network, the second encryption key being exchanged after the third wireless routing node has been verified by the first wireless routing node using the digital signature of the trust authority; communicating the first encrypted data to the third wireless routing node; and engaging in broadcast or multicast communications at the first wireless routing node using a network-wide encryption key distributed by the trust authority to each wireless routing node using a unique link.