Abstract: A device, system and method for securely executing recursive computations over encrypted data in a homomorphically encrypted (HE) space. For a recursive algorithm with sequentially dependent recursive iterations, executing the recursive algorithm in parallel by computing multiple recursive iterations simultaneously over multiple parallel execution iterations and not in sequential order. Each parallel execution iteration may compute a partial HE solution of multiple sequential recursive iterations comprising a known HE part and leaves empty a placeholder call slot for an unknown HE part. Placeholder call slots remain empty and are filled at delayed times at a later parallel execution iteration from when the known part of the same HE computation is computed. A final HE solution is computed in fewer multiple parallel execution iterations than the number of sequential recursive iterations, thereby accelerating the recursive algorithm in HE space.

Abstract: Methods and systems for performing an operation on at least one homomorphically encrypted ciphertext, the method include determining, by a computing device, a value that is an initial approximation of a result of the operation on the at least one homomorphically encrypted ciphertext; and iteratively improving, by the computing device, the value using a recurrence relation wherein a number of iterations is determined based on a predetermined accuracy to minimize an approximation error.

Abstract: Systems and methods for cryptography based on 128 bit integers include: receiving a complex input, the input including a 128-bit number; encrypting by: setting an imaginary part of the input to a predetermined value; encrypting the input using a Fourier transform and a scaling factor; adding a first noise and a second noise to the encrypted input, wherein the second noise obfuscates the first noise; and decrypting by: receiving the encrypted input with added first noise and second noise; estimating a standard deviation of the first noise based on an imaginary part of the received encrypted complex input; computing a standard deviation of the second noise based on the standard deviation of the first noise and a predetermined parameter; and decrypting the encrypted message using an inverse Fourier transform, the first noise, and the second noise.

Abstract: A device, system and method for securely executing recursive computations over encrypted data in a homomorphically encrypted (HE) space. For a recursive algorithm with sequentially dependent recursive iterations, executing the recursive algorithm in parallel by computing multiple recursive iterations simultaneously over multiple parallel execution iterations and not in sequential order. Each parallel execution iteration may compute a partial HE solution of multiple sequential recursive iterations comprising a known HE part and leaves empty a placeholder call slot for an unknown HE part. Placeholder call slots remain empty and are filled at delayed times at a later parallel execution iteration from when the known part of the same HE computation is computed. A final HE solution is computed in fewer multiple parallel execution iterations than the number of sequential recursive iterations, thereby accelerating the recursive algorithm in HE space.