Patent ID: 8566601

Claim:
A computerized method for decrypting a ciphertext using a master secret key and public parameters provided by an authority, comprising: receiving a ciphertext at a receiver module, wherein the ciphertext comprises: encrypted message material, the encryption having been performed based on one or more public parameters provided by an electronic key authority; and an unencrypted portion comprising a plaintext alphanumeric string of arbitrary length; receiving a private secret key at the receiver module, wherein the private secret key comprises: a transformation of one or more elements of a master secret key; and an alphanumeric string pattern acceptor associated with the private secret key and configured to accept only a predefined pattern of plaintext alphanumeric strings of arbitrary length, wherein the string pattern acceptor is a deterministic finite automata or a regular expression; determining with a decryption module if the plaintext alphanumeric string of the ciphertext matches the predefined pattern represented by the string pattern acceptor associated with and comprised by the private secret key by: parsing the ciphertext to obtain the plaintext alphanumeric string of the ciphertext; parsing the private secret key to obtain the string pattern acceptor of the private secret key; processing the plaintext string by applying the string pattern acceptor associated with and comprised by the private secret key to the string to determine if the string is accepted by the string pattern acceptor; decrypting the ciphertext with the decryption module by a transformative operation on the ciphertext if and only if the plaintext string of the ciphertext is accepted by the string pattern acceptor associated with and comprised by the private secret key; and storing the decrypted ciphertext in a computerized data storage device.