Techniques to strengthen one-time pad encryption
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.
1. 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 that is 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; and
the length of the header varies from one message to a subsequent message.
2. The header of claim 1 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.
3. The header of claim 1 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.
4. The header of claim 1 wherein there is a one mapping between at least one flag and one field other than the flag field.
5. The header of claim 1 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.
6. The header of claim 1 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.
7. The header of claim 6 wherein meanings of the flags can be changed after the message has been sent, and before a subsequent message is sent.