Abstract: A method and apparatus for decrypting an input block encrypted under a predetermined key in a cryptographic system having a cryptographic facility providing cryptographic functions for transforming blocks of data. The cryptographic functions include an encryption function for encrypting a block under a predetermined key and a transformation function for transforming a block encrypted under a first key to the same block encrypted under a second key. The cryptographic functions have at least one key pair with the property that successive encryption of a block under the keys of the pair regenerates the block in clear form. The input block is first transformed into an intermediate block encrypted under one of the key pair using the transformation function. The intermediate block is then further encrypted under the other of the key pair using the encryption function to generate an output block successively encrypted under the keys of pair, thereby to regenerate the input block in clear form.

Abstract: The invention disclosed and claimed herein provides a method for a virtual machine, which maps to the V=R region of a host machine's address space, to resume program execution successfully when the host operating system terminates and subsequently restarts successfully after the occurrence of a system incident. The system incident brings the computer system down, but with a reasonable chance that the system will be able to bounce. A bounce occurs when the host operating system nucleus is reinitialized or refreshed. The virtual machine will be allowed to survive the system incident as long as its integrity can be maintained, i.e. as long as its status and in-progress work can be preserved.