Encrypted search cloud service with cryptographic sharing

A system comprising:

• data processing hardware;
• and
• memory hardware in communication with the data processing hardware, the memory hardware storing instructions that when executed on the data processing hardware cause the data processing hardware to perform operations comprising:
• receiving, from a first user device, encrypted data encrypted locally at the first user device by a customer side key stored on the first user device, the customer side key kept secret from the data processing hardware;
• storing, on memory hardware in communication with the data processing hardware, the encrypted data,
• receiving, from a second user device, a search query for a keyword in the encrypted data, the search query comprising a cryptographic search value based on a key for the encrypted data and the keyword;
• determining a portion of the encrypted data associated with the cryptographic search value;
• and
• providing the determined portion of the encrypted data to the second user device.