System and method for maintaining the security of memory contents and computer architecture employing the same

A method of maintaining the security of memory contents, comprising:

• configuring a computer system in which a system memory containing said contents is located in a secure mode;
• transmitting a system memory secure mode signal to a secure memory bridge in said system;
• transmitting a processor secure mode signal to a boot processor in said system;
• transmitting encryption and decryption keys to said secure memory bridge;
• placing an encrypter and a decrypter in said secure memory bridge in data paths therein;
• and
• causing said secure memory bridge to respond to write and read requests using said encryption and decryption keys.

A secure memory system, comprising:

• a bus interconnect;
• a boot processor coupled to, and configured to be a bus master for, said a bus interconnect;
• a secure memory bridge coupled to, and configured to be a bus slave for, said bus interconnect and configured to encrypt and decrypt data associated with said system memory based on a state of a system memory secure mode signal, said boot processor further configured to transmit requests to said secure memory bridge in a secure mode and an unsecure mode;
• system memory coupled to said secure memory bridge;
• a secure read-only memory and an unsecure read-only memory coupled to, and configured to be bus slaves for, said bus interconnect;
• a secure bus bridge coupled to, and configured to be a bus slave for, said bus interconnect;
• a security control module coupled to said secure bus bridge and configured to transmit said system memory secure mode signal and processor secure mode signal to place said system in said secure mode;
• and
• an external device controller coupled to, and configured to be a bus master for, said bus interconnect.