Anonymized data transmission using per-user-functionality secret shares

An apparatus for anonymized encryption of user-provided data, the apparatus comprising at least one processor and at least one memory including program code, the at least one memory and the program code configured to, with the at least one processor, cause the apparatus to at least:

• generate a hashed user identifier based at least in part on a received user identifier;
• transmit the hashed user identifier to an external computing entity;
• receive a data retrieval secret share from the external computing entity, wherein the external computing entity is configured to:
• (i) generate a multiplier value and a secret value using a key derivation model whose master key is generated based at least in part on the hashed user identifier, (ii) generate a linear output value based at least in part on a linear model whose input fields comprise the multiplier value and the secret value, (iii) generate the data retrieval secret share to comprise the linear output value, (iv) generate a user data private key by applying a one-way transformation model to the secret value, (v) encrypt the user-provided data using the user data private key to generate encrypted user-provided data prior to transmission of the encrypted user-provided data;
• in response to receiving the data retrieval secret share, transmit an account identifier and an auditing public key to the external computing entity;
• and
• receive an encrypted data audit secret share from the external computing entity, wherein:
• (i) the encrypted data audit secret share is generated by encrypting a data audit secret share using the auditing public key, and (ii) the data audit secret share is generated based at least in part on the secret value.

A computer program product for anonymized encryption of user-provided data, the computer program product comprising at least one non-transitory computer-readable storage medium having computer-readable program code portions stored therein, the computer-readable program code portions configured to:

• generate a hashed user identifier based at least in part on a received user identifier;
• transmit the hashed user identifier to an external computing entity;
• receive a data retrieval secret share from the external computing entity, wherein the external computing entity is configured to:
• (i) generate a multiplier value and a secret value using a key derivation model whose master key is generated based at least in part on the hashed user identifier, (ii) generate a linear output value based at least in part on a linear model whose input fields comprise the multiplier value and the secret value, (iii) generate the data retrieval secret share to comprise the linear output value, (iv) generate a user data private key by applying a one-way transformation model to the secret value, (v) encrypt the user-provided data using the user data private key to generate encrypted user-provided data prior to transmission of the encrypted user-provided data;
• in response to receiving the data retrieval secret share, transmit an account identifier and an auditing public key to the external computing entity;
• and
• receive an encrypted data audit secret share from the external computing entity, wherein:
• (i) the encrypted data audit secret share is generated by encrypting a data audit secret share using the auditing public key, and (ii) the data audit secret share is generated based at least in part on the secret value.