There is a need for more effective and efficient secure data transmission. This need can be addressed by, for example, solutions for secure data transmission that utilize per-user-functionality secret shares. In one example, a method includes generating a hashed user identifier based on a received user identifier; transmitting the hashed user identifier to an external computing entity; and receiving a data retrieval secret share from the external computing entity, wherein: (i) the data retrieval secret share is selected from a plurality of per-user-functionality secret shares, (ii) the plurality of per-user-functionality secret shares are generated based on a secret value, (iii) the secret value is generated based on the hashed user identifier, (iv) the secret value is used to generate a user data private key, and (v) the external computing entity is configured to encrypt user-provided data using the user data private key prior to transmission of the encrypted user-provided data.

Methods and systems for managing cryptographic keys in on-premises and cloud computing environments and performing multi-party cryptography are disclosed. A cryptographic key can be retrieved from a hardware security module by a key management computer. The key management computer can generate key shares from the cryptographic key, and securely distribute the key shares to computer nodes or key share databases. The computer nodes can use the key shares in order to perform secure multi-party cryptography.

The present invention relates to a communication arrangement configured to allow wired communication between an electronic host device and an electrical slave device, such as between a smart phone and a smart card during an enrollment process. The invention also relates to a method for providing instructions to a user of a smart card during an enrollment process.

Techniques and architectures may be used to provide an environment where a data owner storing private encrypted data in a cloud and a data evaluator may engage in a secure function evaluation on at least a portion of the data. Neither of these involved parties is able to learn anything beyond what the parties already know and what is revealed by the function, even if the parties are actively malicious. Such an environment may be useful for business transactions, research collaborations, or mutually beneficial computations on aggregated private data.

A method of communicating a secret (k.sub.0, k.sub.1) on the Bitcoin blockchain is disclosed. The method comprises sending information identifying secrets selectable by the recipient and receiving a first public key (U.sub.i) of an elliptic curve cryptography system, corresponding to a first secret (S.sub.i) selected for access by the recipient and for which a first private key (m) is accessible to the recipient. A second public key (U.sub.1-i) is received, corresponding to a second secret not selected for access by the recipient, wherein a corresponding second private key is not available to the recipient. First and second secrets encrypted by means of the respective first and second public keys (X.sub.0, X.sub.1) are sent to the recipient, wherein the first secret is accessible to the recipient by means of the first private key, the second secret is inaccessible to the recipient, and the sender is unable to distinguish between the first and second secrets.

The invention is directed to a system that enables an authentication process that involves secure multi-party computation. The authentication process can be performed between a user device operated by a user and an access device. The user device and the access device may conduct the authentication process such that enrollment information and authentication information input by the user is not transmitted between the devices. Instead, the user device may determine and utilize obfuscated values associated with the authentication information. The user device may also determine an obfuscated authentication function that can be utilized to determine an authentication result without revealing enrollment information and authentication information associated with the user. The user can be authenticated based on the authentication result.

A method including at each of a number of client devices receiving a data item, receiving a public key from a second computing system, encrypting the data item using the public key to produce a singly encrypted data item, engaging in an oblivious pseudorandom function protocol with a first computing system using the singly encrypted data item to produce a seed, generating an encrypted secret share using a threshold secret sharing function under which the encrypted secret share cannot be decrypted until a threshold number of encrypted secret shares associated with the same singly encrypted data item are received, and transmitting the encrypted secret share to the first computing system and at the first computing system receiving a number of encrypted secret shares from the number of client devices, processing the number of encrypted secret shares to produce processed data, and transmitting the processed data to a second computing system.

Decision trees can be securely evaluated with reasonable computation speed and bandwidth utilization. A user device encrypts input vectors using a client's public key in an additively homomorphic encryption system. A server computer effectively randomizes the decision tree for each use, such that a value indicative of a path resulting from applying an input vector to the decision tree is different each time the decision tree is used. The server computer homomorphically computes the evaluations of each decision node. The server computer provides the value indicative of the path through the decision tree as one part accessible by the client, and another part accessible by the server. The server computer uses the parts to look up a corresponding output value from a database of output values for each path. In this operation, only the output value corresponding to the combined parts can be retrieved, and only by the intended recipient.

The invention relates to a processing method, including the calculation of one function between a datum to be compared and a reference datum. The function can be written in the form of a sum of: a term that depends on the datum to be compared, a term that depends on the reference datum, and a polynomial, such that all the monomials of the polynomial include at least one coordinate of each datum. The method includes an initialization step including: generating masking data; scrambling reference data by means of a server unit on the basis of said masking data; and calculating, by means of a client unit, the term of the function that depends on the datum to be compared. The method also includes steps for executing the calculation of the function between the datum to be compared and the reference datum, indexed by an index c, during which: the client unit sends the coordinates of the datum to be compared to a secure component, which returns said datum, in a masked form, to said component; the client unit retrieves, from the server unit, the reference datum, indexed by the index c and scrambled by the masking data; and on the basis of the data obtained from the secure component and the server unit, the client unit calculates the sum of the term of the function that depends solely on the reference datum and the polynomial term and adds, to said sum, the term that depends on the datum to be compared, such as to obtain the result of the function.

A security engine may be selected from a plurality of security engines to apply one or more security mechanisms to a section of source code of an application. In some cases, the section of source code may be identified by one or more security mechanism identifiers included in the source code. The security engine may generate machine-readable code that corresponds to the section of source code for which the one or more security mechanisms are to be applied. The machine-readable code may be executed on a plurality of computing devices. In one implementation, applying the security mechanisms to the section of source code may include producing zero-knowledge proofs of knowledge for the section of source code.