The electrical power grid has been undergoing improvements to turn it into a more efficient system known as the Smart Grid. A key element in this upgrade is the Smart Meter. A compromise on the cyber-security of the smart meter would have far-reaching effects affecting millions of users. Effective cryptography is needed to protect it. This work looks at how secret keys for use in encryption can be generated through the use of hash functions. An analysis is carried out on 100 generated keys to see if they have an obvious relationship. The average difference in the bits of the keys were found to be 49.578% indicating strong independence between the keys. This method would thus be a good approach of producing 128 bit keys for use in encryption.