Abstract: A hierarchical cryptographic system has distributed authority among different classes of units in the system. The system may comprise a trusted authority, a first unit authorized by the trusted authority to distribute public and private signature and encryption keys. A second unit accepts for use one or more of the keys only after performing a verification program using the public signature key of the trusted authority. The invention also comprises a unit of a cryptographic system having a processor and a read only memory. The read only memory has stored therein a verification program which includes a public signature key of a trusted authority, and the verification program is made a permanent part of the read only memory during the formation process of the read only memory prior to the application of electrical power to the read only memory.

Abstract: A hierarchical cryptographic system has distributed authority among different classes of units in the system. The system may comprise a trusted authority, a first unit authorized by the trusted authority to distribute public and private signature and encryption keys. A second unit accepts for use one or more of the keys only after performing a verification program using the public signature key of the trusted authority. The invention also comprises a unit of a cryptographic system having a processor and a read only memory. The read only memory has stored therein a verification program which includes a public signature key of a trusted authority, and the verification program is made a permanent part of the read only memory during the formation process of the read only memory prior to the application of electrical power to the read only memory.

Abstract: A secure cryptographic network is established among operational units in a system. A public key cryptosystem is initially used to establish secure communication links. Then, each secure communication link will be provided with a unique private encryption key from a private key cryptosystem. Every operational unit in the system will comprise a secure chip integrated circuit. These secure chips will comprise a programmable processor and a read-only memory. A plurality of personalization stations are used to provide each secure chip with a public/private encryption or signature key pair. The secure chips will execute a program from the read-only memory on the secure chips to verify that the public/private key pair has been received from an authorized source. Each secure chip will also be provided with a chain of authentication certificates originating from a trusted authority.