A method for balancing a cross-domain broadcast network load of a blockchain includes is provided. By evenly distributing the load of cross-domain broadcasting to multiple cross-domain nodes, a utilization rate of a blockchain system can be increased, and ability of processing transactions in the blockchain can be improved. A computer device and a non-transitory computer-readable storage medium are further provided.

A keyboard includes a plurality of keys, a plurality of keyboard components coupled to the keys, and one-time password (OTP) generation hardware integrated with at least some of the keyboard components, where actuating at least one of the keys causes a one-time password to be generated. The OTP generation hardware may be actuated with a dedicated button on the keyboard, by pressing a button on the keyboard that is otherwise used for pairing the keyboard to a device, or by pressing a specific sequence of keys on the keyboard. The keyboard may maintain state information to cause input by the user for OTP generation to be provide to the OTP generation hardware instead of to a device paired with the keyboard. The keyboard may also include a display that is part of the keyboard, where the display shows the one-time password generated by the OTP hardware.

Homomorphic evaluations of functions are performed. The functions include operation(s). Variants of key switching and modulus switching are described and are performed prior to or after the peration(s). A key switching transformation converts a ciphertext with respect to a first secret key and a first modulus to a ciphertext with respect to a second secret key and a second modulus. A key switching transformation converts a first version of a ciphertext with respect to a first secret key and with some number r bits of precision to a second version of the selected ciphertext with respect to a second keys and with some other number r bits of precision. The ciphertexts may be operated on as polynomials represented using evaluation representation, which has benefits for multiplication and automorphism. Further, ciphertexts are associated with an estimate of noise, which is used to determine when to perform modulus switching on the ciphertexts.

Homomorphic evaluations of functions are performed. The functions include operation(s). Variants of key switching and modulus switching are described and are performed prior to or after the peration(s). A key switching transformation converts a ciphertext with respect to a first secret key and a first modulus to a ciphertext with respect to a second secret key and a second modulus. A key switching transformation converts a first version of a ciphertext with respect to a first secret key and with some number r bits of precision to a second version of the selected ciphertext with respect to a second keys and with some other number r bits of precision. The ciphertexts may be operated on as polynomials represented using evaluation representation, which has benefits for multiplication and automorphism. Further, ciphertexts are associated with an estimate of noise, which is used to determine when to perform modulus switching on the ciphertexts.

Techniques for use of carbon nanotubes as an anti-tampering feature and for use of randomly metallic or semiconducting carbon nanotubes in the generation of a physically unclonable cryptographic key generation are provided. In one aspect, a cryptographic key having an anti-tampering feature is provided which includes: an array of memory bits oriented along at least one bit line and at least one word line, wherein each of the memory bits comprises a memory cell, wherein the cryptographic key is stored in the memory cell, and wherein the memory cell is connected to the at least one bit line; and a metallic carbon nanotube interconnect which connects the memory cell to the at least one word line. A cryptographic key and method for processing the cryptographic key are also provided.

Homomorphic evaluation of a function is performed on input ciphertext(s), which were encrypted using a public key of an encryption scheme that also includes multiple secret keys and multiple integer moduli. The homomorphic evaluation of the function includes performing operations(s) on the input ciphertexts. The function includes operation(s) including one or more of addition, multiplication, and automorphism. A key-switching transformation is performed on selected input ciphertext(s), and includes converting a first version of a selected ciphertext with respect to a first of the multiple secret keys and a first modulus to a second version of the selected ciphertext with respect to a second of the multiple secret keys and a second modulus, where the second modulus is an integer factor p times the first modulus, p>1. Each of the key switching transformations is performed prior to or after the operation(s) are evaluated. Results of the operation(s) are output.

A cryptographic system having a plurality of rotors or electronic equivalents using displacement tables. A rotor movement controller, in accordance with a rotor selection value, selectively moves one or more of the rotors or the electronic equivalent of the rotors for each data input value. Contiguous rotor selection values have a triangle or sawtooth shape. A key-driven displacement look-up table randomizes the selection values. The rotor wirings or displacement tables each have N displacement values. The N displacement values are one to N1 inclusive once and N/2 twice and arranged in a sequence that forms a single loop. Additionally, the N displacement values may be arranged in a sequence that is self-reciprocal so that no change in the rotors or displacement tables is needed whether encrypting or decrypting except for selectively adding a factor of N/2 when indexing the displacement tables or setting the initial position of the rotors.

Techniques for use of carbon nanotubes as an anti-tampering feature and for use of randomly metallic or semiconducting carbon nanotubes in the generation of a physically unclonable cryptographic key generation are provided. In one aspect, a cryptographic key having an anti-tampering feature is provided which includes: an array of memory bits oriented along at least one bit line and at least one word line, wherein each of the memory bits comprises a memory cell, wherein the cryptographic key is stored in the memory cell, and wherein the memory cell is connected to the at least one bit line; and a metallic carbon nanotube interconnect which connects the memory cell to the at least one word line. A cryptographic key and method for processing the cryptographic key are also provided.

A homomorphic evaluation of a function is performed on input ciphertext(s), which were encrypted using an encryption scheme that includes multiple integer moduli. Each ciphertext contains one or more elements of an m-th cyclotomic number field, where m is an integer. Each ciphertext which is defined relative to one of the moduli q, each element a(X) of the m-th cyclotomic number field is represented via a matrix, with each row i of the matrix corresponding to an integer factor p.sub.i of the modulus q and each column j corresponding to a polynomial factor F.sub.j(X) of the m-th cyclotomic polynomial .sub.m(X) modulo q. Content of the matrix in row i and column j corresponds to the element a(X) modulo p.sub.i and F.sub.j(X). Performing the homomorphic evaluation of the function further includes performing operation(s) using one or more matrices from one or more of the ciphertexts.

Homomorphic evaluation of a function is performed on input ciphertext(s), which were encrypted using a public key of an encryption scheme that also includes multiple secret keys. Each input ciphertext includes multiple real numbers that are kept with finite precision. Performing the homomorphic evaluation of the function includes performing operation(s). Performing each of one or more operations includes the following. A key-switching transformation is performed on selected ciphertext(s), including converting a first version of a selected ciphertext with respect to a first of the secret keys and with some number r bits of precision to a second version of the selected ciphertext with respect to a second of the secret keys and with some other number r bits of precision, r>r. Each key switching transformation is performed prior to or after the operation(s) are evaluated. Results of the operation(s) are output.