PROCESSING APPARATUS, PROCESSING METHOD, STORAGE MEDIUM, AND ENCRYPTION PROCESSING SYSTEM

A processing apparatus includes at least one processor configured to function as: an input unit that receives encrypted data based on homomorphic encryption as an input; and a process execution unit that executes a predetermined process by using the encrypted data while maintaining a secret state by encryption and includes one or more processing units. At least one of the processing units is a multiplication corresponding processing unit for executing a calculation in a ciphertext space corresponding to a processing of multiplying plaintext data by a predetermined multiplier. The multiplication corresponding processing unit executes a calculation in the ciphertext space corresponding to a calculation of multiplying the plaintext data by an adjustment multiplication value on first encrypted data input from a preceding stage and outputs resulting data. The adjustment multiplication value is obtained by multiplying the predetermined multiplier by a predetermined adjustment value for the multiplication corresponding processing unit and by performing an integer processing.