We claim:
1) A system for performing homomorphic aggregation over
encrypted data, wherein the system comprises:
an encryption engine executed by a processor executing program instructions stored in a memory and configured to:
convert an input dataset based on a query received via a user interface into one or more defined range values, wherein the input dataset is converted into one or more defined range values based on a conversion value matrix;
encrypt the defined range values of the input dataset to a first cipher text matrix;
encrypt the conversion value matrix into a second cipher text matrix; and
transmit the first cipher text matrix and the second cipher text matrix to a computation server for generating an aggregated cipher text matrix;
a decryption engine executed by a processor executing program instructions stored in a memory and configured to:
receive the aggregated cipher text matrix from the computation sever;
decrypt the aggregated cipher text matrix into a decrypted result matrix; and
perform an aggregation operation by counting a pre¬defined digit in each column of the decrypted result matrix.
2) The system as claimed in claim 1, wherein the
aggregated cipher text matrix is generated based on a
computation operation performed between the first cipher
text matrix and the second cipher text matrix in the
computation server.
3) The system as claimed in claim 1, wherein the
encryption engine comprises a range conversion unit

configured to convert the input dataset based on the query received from the user interface into defined range values.
4) The system as claimed in claim 3, wherein the range
conversion unit converts the input dataset based on a
condition specified in the query received via the user
interface.
5) The system as claimed in claim 1, wherein the encryption engine comprises an encryption unit configured to encrypt the converted range values of the input dataset to the first cipher text matrix and encrypt the conversion value matrix into the second cipher text matrix.
6) The system as claimed in claim 1, wherein the decryption engine comprises a decryption unit configured to decrypt the aggregated cipher text matrix into the decrypted result matrix.
7) The system as claimed in claim 1, wherein the decryption engine comprises an aggregation unit configured to perform the aggregation operation by counting the pre¬defined digit in each column of the decrypted result matrix, the pre-defined digit being a digit A0'.
8) The system as claimed in claim 1, wherein the system further comprises a key generation unit in communication with the decryption engine and the encryption engine, the key generation unit being configured to generate a secret key for the decryption engine and a public key for the encryption engine.
9) The system as claimed in claim 1, wherein the decryption unit is configured to decrypt the aggregated cipher text matrix using a secret key.

10) The system as claimed in claim 1, wherein the range conversion unit uses the public key to encrypt the defined range values of the input dataset to the first cipher text matrix and encrypt the conversion value matrix into the second cipher text matrix.
11) The system as claimed in claim 1, wherein the encryption engine transmits the first cipher text matrix and the second cipher text matrix to the computation server for generating the aggregated cipher text matrix.
12) A computer implemented method for performing homomorphic aggregation over encrypted data, wherein the method is implemented by at least one processor executing program instructions stored in a memory, the method comprising:
converting an input dataset based on a query received via a user interface into one or more defined range values, wherein the input dataset is converted into one or more defined range values based on a conversion value matrix;
encrypting the defined range values of the input dataset into a first cipher text matrix;
encrypting the conversion value matrix into a second cipher text matrix;
performing a computation operation between the first cipher text matrix and the second cipher text matrix to generate an aggregated cipher text matrix;
decrypting the aggregated cipher text matrix into a decrypted result matrix; and
performing an aggregation operation by counting a pre-defined digit in each column of the decrypted result matrix.
13) The method as claimed in claim 12, wherein the
aggregation operation is performed by counting the pre-

defined digit in each column of the decrypted result matrix, the pre-defined digit being a digit A0'.
14) The method as claimed in claim 12, wherein a secret key is used to decrypt the aggregated cipher text matrix.
15) The method as claimed in claim 12, wherein a public key is used to encrypt the converted range values of the input dataset to the first cipher text matrix and encrypt the conversion value into the second cipher text matrix.
16) The method as claimed in claim 12, wherein the conversion of the input dataset into the defined range values based on the query is as per a condition specified in the query.