The present invention presents a public key cryptographic system and
method called Absolute Public Key Cryptography that survives private key
compromise and offers two-way communication security. Communications are
secured even when the private key is revealed. It provides security to
the private-to-public side communications and also allows short keys to
be used with mobile devices that have low processing power. The system
uses keys with two or more components and encrypts a message into the
same number of cipher versions. The cipher versions are delivered to the
destination in source routing mode, or hop-by-hop routing mode with a
small time gap. The recipient performs certain mathematical operations on
all the cipher versions and obtains the original message. All the
versions are necessary for obtaining the original message. Even a single
version missing leads to produce a junk for an attacker. As an attacker
at an intermediary IP router can not have all the cipher versions
available, he can not obtain the original message even when he knows the
private key. This is why the system is called Absolute Public Key
Cryptography. The robustness against private key compromise is achieved
by blinding the public key through adding a random number to each of its
components before encryption. When the encryption process is complete,
the random number is discarded and the cipher versions are delivered to
the recipient. The effect of blinding is made void by the actual intended
recipient, who has all the cipher versions available. Robustness is also
achieved another way, that is, by choosing the encrypting key such that
each of its components has a common factor with Euler Totient Function of
the key modulus, and there is no common factor among all the components.
This makes it harder for an attacker to decrypt a single cipher version
of the message into the original message and thereby allows smaller keys
to be used for mobile communications. Communication in both directions is
secured by using two different key pairs, one for public-to-private-side
and the other for private-to-public-side communications.
