Systems and methods for efficient decryption of attribute-based encryption

A computerized method for decryption, comprising:

• generating an access structure having one or more attributes selected from a set of allowed attributes;
• generating a private secret key, wherein the private secret key is associated with the access structure;
• storing the private secret key in a computerized data storage device on a server;
• encrypting a first portion of the private secret key using a symmetric encryption function;
• storing the first portion of the private secret key in the computerized data storage device on the server;
• transmitting a second portion of the private secret key to a mobile device;
• receiving the second portion of the private secret key at the mobile device;
• receiving a ciphertext at the mobile device, the ciphertext having been encrypted using a transformative operation on one or more public parameters and wherein the ciphertext is associated with an arbitrary number of attributes in the attribute set;
• if the attributes in the ciphertext satisfy the access structure, decrypting the ciphertext at the mobile device using a number of pairing operations, wherein the number of pairing operations used to decrypt the ciphertext can be arbitrarily selected to be within a range between two and the number of attributes with which the ciphertext is associated;
• and
• storing the decrypted ciphertext in a computerized data storage device on the mobile device;
• wherein a time required for decrypting the ciphertext using a number of pairing operations selected to be within a range between two and the number of attributes comprising the attribute set is less than the time required for decrypting the ciphertext using a number of pairing operations equal to the number of attributes associated with the ciphertext needed to satisfy the access structure.

A system for secure message processing, the system comprising:

• a key generation computing device module configured for:
• generating a private secret key, wherein the private secret key comprises one or more results of a first transformative operation on a master secret key and wherein the private secret key is associated with an access structure;
• a data storage computing device module configured for storing the private secret key in a computerized data storage device;
• and
• a decryption computing device module configured for:
• receiving the private secret key;
• receiving a ciphertext, the ciphertext having been encrypted using a second transformative operation on one or more public parameters and wherein the ciphertext is associated with a plurality of attributes in an attribute set;
• decrypting the ciphertext using a number of pairing operations, wherein the number of pairing operations used to decrypt the ciphertext can be arbitrarily selected to be within a range between two and the number of attributes with which the ciphertext is associated;
• and
• storing the decrypted ciphertext in a computerized data storage device;
• wherein a time required for decrypting the ciphertext using a number of pairing operations selected to be within a range between two and the number of attributes comprising the attribute set is less than the time required for decrypting the ciphertext using a number of pairing operations equal to the number of attributes associated with the ciphertext needed to satisfy the access structure.

A computerized method for decryption, comprising:

• receiving a ciphertext, the ciphertext having been encrypted using a first transformative operation on one or more public parameters and wherein the ciphertext is associated with an access structure;
• receiving a private secret key, wherein the private secret key comprises one or more results of a second transformative operation on a master secret key and wherein the private secret key is associated with an attribute set;
• if the attributes in the attribute set satisfy the access structure, decrypting the ciphertext using a number of pairing operations, wherein the number of pairing operations used to decrypt the ciphertext can be arbitrarily selected to be within a range between two and the number of attributes comprising the attribute set;
• and
• storing the decrypted ciphertext in a computerized data storage device;
• wherein a time required for decrypting the ciphertext using a number of pairing operations selected to be within a range between two and the number of attributes comprising the attribute set is less than the time required for decrypting the ciphertext using a number of pairing operations equal to the number of attributes associated with the secret key needed to satisfy the access structure.