Abstract: Apparatus for distributing the processing of data across a plurality of loci of control which are connected by a mail system. The apparatus includes a package which contains files of various types and a route specifying the order in which the package is to be circulated among the loci and the processing to be done at each locus. Each locus includes programs executable by users which can manipulate the contents of the package. The programs automatically take the type of file being manipulated into account. The manipulations include modifying the unexecuted portion of the route. Each locus further includes a process which executes the route as modified, a process which tracks the package and receives control commands, and a process which handles errors detected by the other components or by users. The tracking processes maintain data bases for locating the package.

Abstract: An encryption and decryption circuit and method using subkeys which is therefore particularly useful for the encryption and decryption of database information. Each data field has a corresponding write key and a different read key. A database record is encrypted by multiplying each field by its corresponding write key and adding up all such products modulo the product of all read keys. The read keys must be prime numbers and the write keys must satisfy a certain relationship with respect to the read keys. A database record may have a single field decrypted by dividing the encrypted record by the read key for that field and taking the remainder. The security of each field may thereby be individually controlled without compromising the security of the entire record.

Abstract: A complete substitution permutation enciphering and deciphering circuit and method for transforming a plaintext signal into an enciphered signal which is secure during transmission. After receipt, the enciphered signal is transformed back into the original plaintext signal by use of a similar circuit and method. A complete substitution permutation enciphering and deciphering circuit is constructed by interconnecting a number of substitution boxes. Each substitution box is complete, that is each binary bit of the substitution box output is dependent on all binary bits of the substitution box input for all possible combinations of input signals. When such substitution boxes are connected according to the invention, the substitution permutation enciphering and deciphering circuit formed thereby is complete in the sense that every output signal of the circuit is dependent on all input signals of the circuit.