A system for making digital signatures includes plural signers determining cleartext bits to sign in response to a hash of a pre-image known to the respective signer and message. Another system uses one-way functions and a plurality of authentication paths per signature. A key information distribution system uses physical media, physical media revealing means, and changing the configuration of the physical media revealing means to reveal secret indicia to observers.

The present disclosure generally relates to code verification. For example, aspects of the present disclosure include systems and techniques for determining whether two codes are a match. One example method generally includes generating, at a first device, first encrypted data at least in part by encrypting verification data using a public key; generating, at the first device, second encrypted data at least in part by encrypting a random factor using the public key; generating, at the first device, a key for the verification data; generating, at the first device, third encrypted data at least in part by encrypting the key using the public key; computing, at the first device, fourth encrypted data at least in part by applying homomorphic encryption function to the first encrypted data, the second encrypted data, and the third encrypted data; and sending, to a second device, the fourth encrypted data.

A system is provided for electronic data encryption and decryption using a consensus draft process. In particular, the system may use a custom encryption algorithm that generates an array with a number of entries that is dependent on the number of computing devices that participate in the encryption process. The encryption algorithm may cause a first computing device to open and read the array, randomly select and remove an entry, and pass on the remaining entries to a second computing device. The second computing device may then open and read the array, randomly select and remove an entry, then pass the remaining entries to a third computing device. The process may be executed in a reiterative manner until the entire array is distributed among the participating computing devices. In this way, encryption of data may be performed without revealing shared information among the participating computing devices.

The present invention relates to methods for secure computation and/or communication. Entangled photons (118) are generated such that each participating party receives a series of optical pulses. Each party has private information (110, 112) which are never transmitted through public or private communication channels. Instead, each party converts their respective private information (110, 112) into measurement bases via an encryption process (114, 116) which are then applied to the entangled photons (118). After the measurement process, e.g., quantum frequency conversion (122, 124), reference indices are announced (124, 126) so that computation can be performed (128) without revealing the private information directly or indirectly.

New and efficient protocols are provided for privacy-preserving machine learning training (e.g., for linear regression, logistic regression and neural network using the stochastic gradient descent method). A protocols can use the two-server model, where data owners distribute their private data among two non-colluding servers, which train various models on the joint data using secure two-party computation (2PC). New techniques support secure arithmetic operations on shared decimal numbers, and propose MPC-friendly alternatives to non-linear functions, such as sigmoid and softmax.

A method includes obtaining, from a server, a filter including a set of encrypted identifiers each encrypted with a server key controlled by the server. The method includes obtaining a request that requests determination of whether a query identifier is a member of a set of identifiers corresponding to the set of encrypted identifiers. The method also includes transmitting an encryption request to the server that requests the server to encrypt the query identifier. The method includes receiving, from the server, an encrypted query identifier including the query identifier encrypted by the server key and determining, using the filter, whether the encrypted query identifier is not a member of the set of encrypted identifiers. When the encrypted query identifier is not a member of the set of encrypted identifiers, the method includes reporting that the query identifier is not a member of the set of identifiers.

A secret share value [q] of a quotient q of a/p is obtained through secure computation using a secret share value [a] and a modulus p and [a/d.sub.0]=[(a+qp)/d.sub.0]−[q]p/d.sub.0, . . . , [a/d.sub.n−1 ]=[(a+qp)/d.sub.n−1]−[q]p/d.sub.n−1 are obtained and output through secure computation using secret share values [a] and [q], divisors d.sub.0, . . . , d.sub.n−1, and a modulus p. Here, [μ] is a secret share value of μ, a is a real number, n is an integer equal to or greater than 2, d.sub.0, . . . , d.sub.n−1 are divisors of real numbers, p is a modulus of a positive integer, and q is a quotient of a positive integer.

According to an aspect, a method may include receiving a candidate value; in response to a received candidate value matching one of the entries in the table, incrementing a corresponding count; in response to the received candidate value not matching one of the entries in the table and the table not exceeding a threshold size, adding an entry to the table; in response to the received candidate value not matching one of the entries in the table and the table exceeding the threshold size, decrementing the counts in the table and deleting entries having a count of zero; adding noise to the corresponding counts in the entries of the table and deleting any noisy corresponding counts less than a threshold value; and outputting at least a portion of the table as the top-k value result set.

A secure multi-party computing system performs a multi-pivot partial sorting operation on a secret shared array of values. The use of multiple pivots supports efficient computations in a multi-party computation setting. Partial sorting determines percentile values without the need for a full sort. The secret shared array is first permuted by a secret random permutation. A multi-pivot sort, which can be a partial sort, is performed on the permuted array to obtain a public sorting permutation. The multi-pivot sort uses oblivious comparisons that produce secret shared Boolean indications of whether one secret shared value is less than another. The Boolean indications are revealed and used to produce the public sorting permutation, which in turn, is applied to the secret random permutation to obtain a secret shared sorting permutation. The secret shared sorting permutation is then applied to the secret shared array to obtain a sorted secret shared result.

A transaction consensus processing method for a blockchain is provided. A target node that initiates a proposition performs compression processing on proposed transaction data based on a compression algorithm, and fragments the compressed transaction data into a number of data fragments based on an erasure code algorithm. The method includes: receiving a data fragment of the transaction data that is sent by the target node in a unicast mode, data fragments sent by the target node to nodes in the unicast mode being different; broadcasting the received data fragment to other nodes, and receiving data fragments of the transaction data that are broadcast by the other nodes; performing data recovery on the received data fragment based on an erasure code reconstruction algorithm, performing decompression processing on the recovered transaction data based on a decompression algorithm to obtain original content of the transaction data, and completing the consensus.