Techniques to strengthen one-time pad encryption

Abstract

Apparati, methods, and computer-readable media for strengthening a one-time pad encryption system. A method embodiment of the present invention comprises the steps of encrypting plaintext ( 1 ) with an OTP key ( 2 ) in an XOR operation to produce ciphertext ( 3 ); and obfuscating the ciphertext ( 3 ) with an AutoKey ( 4 ) in an XOR operation to produce AutoKeyed ciphertext ( 5 ), wherein the AutoKey ( 4 ) is a reusable key.

What is claimed is: 
     
         1 . A computer-implemented method for strengthening an OTP encryption system, said method comprising the steps of:
 encrypting plaintext with an OTP key in an XOR operation to produce ciphertext; and   obfuscating the ciphertext with an AutoKey in an XOR operation to produce AutoKeyed ciphertext, wherein the AutoKey is a reusable key.   
     
     
         2 . The method of  claim 1  wherein the AutoKey is uniquely linked to a set of OTP keys. 
     
     
         3 . The method of  claim 1  wherein the AutoKey is uniquely linked to a Kernel Key, wherein the KernelKey is a reusable key. 
     
     
         4 . The method of  claim 3  wherein the plaintext comprises a plaintext header and a plaintext body, said method further comprising the step of obfuscating the plaintext header with the KernelKey. 
     
     
         5 . The method of  claim 3  further comprising the step of obfuscating byproducts of the OTP encryption with the KernelKey. 
     
     
         6 . A computer-implemented method for strengthening an OTP encryption system, said method comprising the steps of:
 obfuscating a plaintext header with a KernelKey in an XOR operation to produce a ciphertext header, wherein:
 the KernelKey is a reusable key; and 
 the plaintext header contains information useful in processing an associated plaintext body. 
   
     
     
         7 . The method of  claim 6  wherein the information comprises items from the group of items consisting of:
 identity of an intended recipient of the plaintext body; 
 length of the plaintext body; 
 identity of an OTP key; and 
 key offset of said OTP key for use in decrypting the plaintext body. 
 
     
     
         8 . The method of  claim 6  further comprising the step of de-obfuscating the ciphertext header, thereby recovering the plaintext header, by combining the ciphertext header with the KernelKey in an XOR operation without using a key offset. 
     
     
         9 . The method of  claim 8  wherein the de-obfuscating step is performed using an indexing technique comprising:
 selecting a preselected index location within the plaintext header; and 
 finding said index location within the KernelKey. 
 
     
     
         10 . The method of  claim 6  wherein no consecutive n bytes are repeated within the KernelKey, where n is a positive integer at least equal to 2. 
     
     
         11 . The method of  claim 6  wherein the KernelKey contains a randomly located header comprising:
 a GUID; and 
 a portion of an AutoKey, wherein the AutoKey is a reusable key. 
 
     
     
         12 . The method of  claim 11  wherein the AutoKey is used to obfuscate ciphertext produced by the OTP encryption system. 
     
     
         13 . A computer-readable set of data comprising a variable persistent header for use in a computer-implemented communications system, said header comprising:
 a plurality of fields containing information useful in processing a message associated with the header, said plurality of fields being located independently of the location of the message and not containing any synchronization information regarding the location of the header vis-à-vis the location of the message; wherein:   one of the fields comprises a set of flags indicating which of said other fields are persisted from a sender of the message to a recipient of the message.   
     
     
         14 . The header of  claim 13  wherein at least one of the fields contains information pertaining to:
 identity of an intended recipient of the message; 
 length of the message; 
 identity of a one-time pad (OTP) key used to encrypt the message; or 
 key offset of said OTP key, given as a number of bits of a starting point within the OTP key, for use in decrypting the message. 
 
     
     
         15 . The header of  claim 13  wherein the header is contained within an obfuscation key that is used to perform at least one of the following two tasks:
 obfuscate byproducts of encryption; 
 obfuscate the header. 
 
     
     
         16 . The header of  claim 13  wherein there is a one-to-one mapping between at least one flag and one field other than the flag field. 
     
     
         17 . The header of  claim 13  wherein there is a one-to-many mapping between at least one of the flags and at least two fields other than the flag field. 
     
     
         18 . The header of  claim 13  wherein meanings of the flags are agreed to by a sender of the message and a recipient of the message prior to the message being sent from the sender to the recipient. 
     
     
         19 . (The header of  claim 18  wherein meanings of the flags can be changed after the message has been sent, and before a subsequent message is sent. 
     
     
         20 . At least one computer-readable medium containing computer program instructions for strengthening an OTP encryption system, said computer program instructions performing the steps of:
 encrypting plaintext with an OTP key in an XOR operation to produce ciphertext; and   obfuscating the ciphertext with an AutoKey in an XOR operation to produce AutoKeyed ciphertext, wherein the AutoKey is a reusable key.   
     
     
         21 . At least one computer-readable medium containing computer program instructions for strengthening an OTP encryption system, said computer program instructions performing the steps of:
 obfuscating a plaintext header with a KernelKey in an XOR operation   to produce a ciphertext header, wherein:   the KernelKey is a reusable key; and   the plaintext header contains information useful in processing an associated plaintext body.