Privacy-preserving log analysis

A method for establishing cryptographic electronic transmission of an electronic utility log between a utility computer terminal of a utility and a service provider host computer terminal of a service provider host over a network channel to determine misuse of the utility based on suspicious events in the electronic utility log, the method comprising:

• generating, by the utility computer terminal, an encrypted electronic utility log from an unencrypted electronic utility log by encrypting the unencrypted electronic utility log using a k-deterministic encryption scheme comprising:
• generating an encryption key using a key generation function KG of a probabilistic encryption scheme including an encryption function E;
• generating an additional random bit string s;
• generating k random components using a pseudo-random number generator with k, s, and the unencrypted electronic utility log as parameters;
• encrypting the entire unencrypted electronic utility log using the encryption function E with one of the k random components, selected uniformly at random as part of the input, to output a single ciphertext from one of at most k probabilistically-computed ciphertexts, k being an integer greater than 1;
• generating an encrypted query by encrypting a query using the k-deterministic encryption scheme at the utility computer terminal;
• transmitting the encrypted electronic utility log and the encrypted query from the utility computer terminal to the service provider host computer terminal so that the encrypted electronic utility log can be analyzed on the service provider host computer terminal using the encrypted query;
• receiving, at the utility computer terminal, an encrypted electronic analysis result from the service provider host computer terminal, the encrypted electronic analysis result being an encrypted version of an electronic analysis result based on the electronic utility log and the encrypted query, without the service provider host decrypting the encrypted electronic utility log or the encrypted query;
• decrypting, by the utility computer terminal, the encrypted electronic analysis result to generated a decrypted analysis result;
• verifying, by the utility, the decrypted analysis result;
• and
• detecting, by the utility, the suspicious events based on the encrypted electronic analysis result;
• and
• determining, by the utility, that the misuse occurred based on the suspicious events.

A method for establishing cryptographic electronic transmission of an electronic utility log between a utility computer terminal of a utility and a service provider host computer terminal of a service provider host over a network channel to determine misuse of the utility based on suspicious events in the electronic utility log, the method comprising:

• generating, by the utility computer terminal, an encrypted electronic utility log from an unencrypted electronic utility log by encrypting the electronic utility log using a k-deterministic encryption scheme comprising:
• generating an encryption key using a key generation function KG of a probabilistic
• encryption scheme including an encryption function E;
• generating an additional random bit string s;
• generating k random components using a pseudo-random number generator with k, s, and the unencrypted electronic utility log as parameters;
• encrypting the entire unencrypted electronic utility log using the encryption function E with one of the k random components, selected uniformly at random as part of the input, to output a single ciphertext from one of at most k probabilistically-computed ciphertexts, k being an integer greater than 1;
• generating, by the utility computer terminal, an encrypted query by encrypting a query using the k-deterministic encryption scheme;
• transmitting, by the utility computer terminal, the encrypted electronic utility log and the encrypted query from the utility computer terminal to the service provider host computer terminal;
• analyzing, by the service provider host computer terminal, the encrypted electronic utility log using the encrypted query;
• generating, by the service provider host computer terminal, an encrypted electronic analysis result without decrypting the encrypted electronic utility log or the encrypted query;
• transmitting, by the service provider host computer terminal, the encrypted electronic analysis result to the utility computer terminal;
• decrypting, by the utility computer terminal, the encrypted electronic analysis result to generate a decrypted analysis result;
• verifying, by the utility, the decrypted analysis result;
• detecting, by the utility, the suspicious events based on the encrypted electronic analysis result;
• and
• determining, by the utility, that the misuse occurred based on the suspicious events.

A system configured to establish cryptographic electronic transmission of an electronic utility log between a utility computer terminal of a utility and a service provider host computer terminal of a service provider host over a network channel to determine misuse of the utility based on suspicious events in the electronic utility log, the system comprising:

• the utility computer terminal having a first non-transitory computer readable medium, the utility computer terminal being configured to:
• generate an encrypted electronic utility log from an unencrypted electronic utility log by encrypting the unencrypted electronic utility log using a k-deterministic encryption scheme comprising:
• generating an encryption key using a key generation function KG of a probabilistic encryption scheme including an encryption function E;
• generating an additional random bit string s;
• generating k random components using a pseudo-random number generator with k, s, and the unencrypted electronic utility log as parameters;
• encrypting the entire unencrypted electronic utility log using the encryption function E with one of the k random components, selected uniformly at random as part of the input, to output a single ciphertext from one of at most k probabilistically-computed ciphertexts, wherein k is an integer greater than 1;
• generate an encrypted query by encrypting a query using the k-deterministic encryption scheme;
• and
• transmit, via a secure network channel, the encrypted electronic utility log and encrypted query to the service provider host computer terminal;
• and
• the service provider host computer terminal having a second non-transitory computer readable medium, the service provider host computer terminal being configured to:
• receive, via the secure network channel, the encrypted electronic utility log and the encrypted query from the utility;
• analyze the encrypted electronic utility log by using the encrypted query;
• generate an encrypted electronic analysis result without decrypting the encrypted electronic utility log or the encrypted query;
• and
• transmit, via the secure network channel, the encrypted electronic analysis result to the utility;
• wherein the utility computer terminal is further configured to:
• receive, via the secure network channel, the encrypted electronic analysis result from the service provider host computer terminal;
• decrypt the encrypted electronic analysis result to generate a decrypted analysis result;
• verify the decrypted analysis result;
• detect the suspicious events based on the decrypted analysis result;
• and
• determine that the misuse occurred based on the suspicious events.