Various aspects of the disclosure relate to using a verifiable and distributed encoding as a digital currency (e.g., cryptocurrency). According to some embodiments, systems and methods can be executed to transfer cash or “hard” currency responsive to exchange of cryptocurrency supported by blockchain technology. In further example, the systems and methods are tailored to operate within a specified/defined community that ensures the efficient operation of the system by ensuring liquidity of the transfer. According to one embodiment, the system is configured to distribute stable coin, issuing the coin at a discounted value (e.g., relative to a redemption or cash equivalent face value). For example, by issuing coin at a discount the system automatically facilitates peer-to-peer physical cash transfers.

A diamond asset comprising one or more diamonds and an encryption chip is used to asset-back a cryptographic token that can be used to conduct transactions. The cryptographic token is written to a blockchain using a smart contract that is configured to enable a transaction associated with the token in response to two or more of: a signature by the encryption chip, a signature by the owner of the diamond asset, and a validation of a visual layout of the diamond asset.

A system for storing and managing secure information is disclosed that includes a secure identity and profiling system, which serves as a middleman between a user and an entity requesting personally identifiable information (PII) from the user. The system collects the PII from the user and stores it securely, such as in an alternate blockchain in an encrypted form. The location of the that PII within the alternate blockchain may be indexed using smart contracts in a main blockchain that can only be read with an access token generated and supplied by the user's mobile device. When an entity requests PII from the user that has already been collected and securely stored, the user can provide permission to release that PII by providing the access token. The system will use the access token to locate where the PII is stored and release the PII to the requesting entity.

Arrangements for controlling access to a protected entity include receiving a redirected client request to access the protected entity that includes a public key of the client; granting, in response to the received redirected request, access tokens of a first type to a client using the public key of the client; identifying a conversion transaction identifying a request to convert the first type of access tokens with access tokens of a second type, the transaction designating the protected entity; determining a conversion value for converting the first-type access tokens into second-type access tokens based on at least one access parameter; converting, using the conversion value, a first sum of the first-type access tokens into a second sum of second-type access tokens; and granting the client access to the protected entity when the sum of second-type of access tokens is received as a payment from the protected entity.

Embodiments are directed to generating and training a distributed machine learning model using data received from a plurality of third parties using a distributed ledger system, such as a blockchain. As each third party submits data suitable for model training, the data submissions are recorded onto the distributed ledger. By traversing the ledger, the learning platform identifies what data has been submitted and by which parties, and trains a model using the submitted data. Each party is also able to remove their data from the learning platform, which is also reflected in the distributed ledger. The distributed ledger thus maintains a record of which parties submitted data, and which parties removed their data from the learning platform, allowing for different third parties to contribute data for model training, while retaining control over their submitted data by being able to remove their data from the learning platform.

An incorrect copy of a record of data can be prevented from being transmitted to a distributed ledger system. A first file can be received and can include information, in audio or video form, with a description of a subject matter of the record of data and with an authorization to transmit the copy to the distributed ledger system. The first file can be sent to a device. A second file can be received from the device and can include information that confirms that the description of the subject matter, included in the first file, is correct, and that confirms that an entity, which controlled production of the first file, has permission to authorize causing the copy to be transmitted to the distributed ledger system. The correct copy can be caused, based on a receipt of the first and the second files, to be transmitted to the distributed ledger system.

Permissioned blockchains with off-chain storage establish integrity and no-later-than date-of-existence for documents, leveraging records containing hash values of documents. When a document's integrity or date is challenged, a new hash value is compared with a record in the blockchain. Proving date-of-existence (via hash value in a publication and/or SMS) for the block containing the record establishes no-later-than date-of-existence for the document. Permissioning monetizes operations, enforcing rules for submission rights and content, thereby precluding problematic material (privacy, obscenity, malicious logic, copyright violations) that threatens long-term viability. Compact records and off-chain storage in a document corral (with quarantine capability) preserve document confidentiality and ease storage burdens for distributed blockchain copies. Using multiple hash values for each document hardens against preimage attacks with quantum computing. Daisy chaining records establishes that relationships existed among documents at registration. Self-addressed blockchain registration (SABRe) permits documents to self-identify their blockchain record address (block ID, index).

An example operation may include one or more of monitoring, by a blockchain node, a delivery of a service to a first node from a second node based on a service contract and an order retrieved from a blockchain, determining, by the blockchain node, an incremental charge for a partial delivery of the service based on the monitoring, and executing, by the blockchain node, a smart contract to issue the incremental charge for the partial delivery of the service, and responsive to a resolution of a dispute raised for the incremental charge, add the incremental charge to an incremental invoice.

Disclosed are techniques and an apparatus for accessing a smart contract library that may include a number of templates of different legal contracts implementable as a smart contract between respective parties. Each template may include a number of sections having different contractual terms and conditions and fillable fields for specific contract terms. Each respective section of the number of sections includes programming code operable to enforce conformance with specific section-related contractual terms and conditions of the respective section and with any specific contract terms input to a fillable field of the respective section. A first user address generated based on cryptographic keys may be associated with a contract-creating computing device in a private blockchain. The first user address may be associated with the first user in the private blockchain. A finalized smart contract may have a smart contract address generated from the first user address and a nonce value.

Performing cryptographic operations such as encryption and decryption may be computationally expensive. In some contexts, initialization vectors and keystreams operable to perform encryption operations are generated and stored in a repository, and later retrieved for use in performing encryption operations. Multiple devices in a distributed system can each generate and store a subset of a larger set of keystreams.