This document describes example methods, devices, and computing systems to rank a data string into a ranking value, and de-rank a second value representative of a variation of the ranking value (e.g., cipher value) into a second data string (e.g., cipher string), using a tree data-structure. The tree data-structure defines a domain of values representative of all variations of a set of characters that satisfy a format within which the data string is defined. The ranking value is identified with respect to a first offset value calculated for individual characters of the data string relative to the domain of values of the tree data-structure. The second value is de-ranked into a second data string of individual characters identified with respect to a second offset value calculated in the domain of values of the tree data-structure relative to the second value. This method may be performed using the tree data-structure to rank a data string into a ranking value, and de-rank a cipher version of the ranking value into a cipher string. Similarly, this method may be performed to accomplish the reverse process of ranking a cipher string to a ranking value, and de-ranking a decrypted version of the ranking value to a decrypted data string.

Using composite cipher technology a single ciphertext C will decrypt to plaintext Pi using key Ki, and to plaintext Pj≠Pi using key Kj≠Ki, thereby a single file C will carry any number of distinct messages so that each key holder will see in C the message intended for them. Applicable for complex project management where frequent changes and large number of people are involved. Also in email systems where a single email will deliver a shared message plus individual messages to selected readers.

This document describes example methods, devices, and computing systems to rank a data string into a ranking value, and de-rank a second value representative of a variation of the ranking value (e.g., cipher value) into a second data string (e.g., cipher string), using a tree data-structure. The tree data-structure defines a domain of values representative of all variations of a set of characters that satisfy a format within which the data string is defined. The ranking value is identified with respect to a first offset value calculated for individual characters of the data string relative to the domain of values of the tree data-structure. The second value is de-ranked into a second data string of individual characters identified with respect to a second offset value calculated in the domain of values of the tree data-structure relative to the second value. This method may be performed using the tree data-structure to rank a data string into a ranking value, and de-rank a cipher version of the ranking value into a cipher string. Similarly, this method may be performed to accomplish the reverse process of ranking a cipher string to a ranking value, and de-ranking a decrypted version of the ranking value to a decrypted data string.

Using composite cipher technology a single ciphertext C will decrypt to plaintext Pi using key Ki, and to plaintext Pj≠Pi using key Kj≠Ki, thereby a single file C will carry any number of distinct messages so that each key holder will see in C the message intended for them. Applicable for complex project management where frequent changes and large number of people are involved. Also in email systems where a single email will deliver a shared message plus individual messages to selected readers.

A privacy-preserving, mutual PUF-based authentication protocol that uses soft data to exchange and correlate Helper Data bitstrings instead of PUF response bitstrings as a means of authenticating chips to prevent attacks.

A method and system for protecting passwords offline is disclosed. The invention being comprised of a notebook made from pages having grains of crushed calcium carbonate stone and a combo cipher marker and UV torch. The notebook contains tables and matrices to accommodate the ciphering process, a marker that contains transparent ink to hide passwords and a UV torch to exposes hidden passwords. The passwords themselves are encrypted by means of a process involving character mapping and key codes recorded into the notebook with the combo cipher marker and UV torch. These encrypted passwords remain invisible until the user shines the pages with the UV torch on the cap and passwords can then be retrieved and unscrambled. An object of the invention is to enhance password security by archiving them completely offline and off any electronic networks.

A registration device (200) generates an encryption keyword by encrypting a keyword with a registration key, generates an index including the encryption keyword and identification information which identifies a corresponding ciphertext, generates a conversion key from the registration key and a search key, and registers a plurality of ciphertexts, the index, and the conversion key in a server device (400). A search device (300) generates a search query by encrypting a keyword, and transmits the search query to the server device (400). The server device (400) generates a re-encryption keyword by re-encrypting the search query with the registered conversion key, searches the registered index with the re-encryption keyword, acquires, from the index, the identification information if the encryption keyword is obtained as a search result, extracts a ciphertext identified by the identification information from the registered plurality of ciphertexts, and transmits the extracted ciphertext to the search device (300).

A registration device (200) generates an encryption keyword by encrypting a keyword with a registration key, generates an index including the encryption keyword and identification information which identifies a corresponding ciphertext, generates a conversion key from the registration key and a search key, and registers a plurality of ciphertexts, the index, and the conversion key in a server device (400). A search device (300) generates a search query by encrypting a keyword, and transmits the search query to the server device (400). The server device (400) generates a re-encryption keyword by re-encrypting the search query with the registered conversion key, searches the registered index with the re-encryption keyword, acquires, from the index, the identification information if the encryption keyword is obtained as a search result, extracts a ciphertext identified by the identification information from the registered plurality of ciphertexts, and transmits the extracted ciphertext to the search device (300).

Exploiting the wealth of information in the intricate structure of a network where vertices are interconnected through edgesto insure data integrity between communication partners, where the partners gauge the projected security through the size and complexity of the deployed shared network.

Exploiting the wealth of information in the intricate structure of a network where vertices are interconnected through edgesto insure data integrity between communication partners, where the partners gauge the projected security through the size and complexity of the deployed shared network.