Abstract: According to an example aspect of the present invention, there is provided an apparatus comprising at least one processing core, at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processing core, cause the apparatus at least to obtain a document, segmented into a first number of segments (510), obtain the first number of outputs of a cryptographic operation, such that for each output, a random value and a document segment are employed to generate an input to the cryptographic operation (520), build a Merkle tree based on the outputs of the cryptographic operation (530), and store a top hash of the Merkle tree in a block chain (540).

Abstract: Apparatus, method, computer program product and computer readable medium are disclosed for trusted computing. A method includes, at an isolated processor including a trusted execution environment and an isolated storage, receiving data encrypted with a first public key; decrypting the encrypted data with a first private key; performing calculation on the decrypted data by using an approved program; and providing the calculation result, wherein the approved program is authorized by a smart contract, a unique identifier of the smart contract is stored in the isolated processor, both the approved program and the isolated processor are verified by at least one participant of the smart contract, and the first public key and the first private key are generated by the isolated processor.

Abstract: Apparatus, method, computer program product and computer readable medium are disclosed for trusted computing. A method comprising: at an isolated processor comprising a trusted execution environment and an isolated storage, receiving data encrypted with a first public key; decrypting the encrypted data with a first private key; performing calculation on the decrypted data by using an approved program; and providing the calculation result, wherein the approved program is authorized by a smart contract, a unique identifier of the smart contract is stored in the isolated processor, both the approved program and the isolated processor are verified by at least one participant of the smart contract, and the first public key and the first private key are generated by the isolated processor.

Abstract: According to an example aspect of the present invention, there is provided an apparatus comprising at least one processing core, at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processing core, cause the apparatus at least to obtain a document, segmented into a first number of segments (510), obtain the first number of outputs of a cryptographic operation, such that for each output, a random value and a document segment are employed to generate an input to the cryptographic operation (520), build a Merkle tree based on the outputs of the cryptographic operation (530), and store a top hash of the Merkle tree in a block chain (540).