Digital signature generation using a cold wallet

A system, comprising:

• one or more processors;
• and
• one or more non-transitory computer-readable medium storing code comprising executable instructions, wherein the instructions, when executed, cause the one or more processors to perform steps comprising:
• receiving by two or more nodes of a cold wallet, one or more shares of a private signature key, each node of the cold wallet thereby being in the possession of the one or more shares of the private signature key, and none of the nodes of the cold wallet being in the possession of all shares of the private signature key;
• generating by each node of the cold wallet a pre-signature, based on its share(s) of the private signature key, and transmitting the pre-signature to one of two or more pre-signature nodes, in such a manner that each pre-signature node receives a pre-signature from only one of the nodes of the cold wallet;
• requesting by a signing application a signature and transmitting a message to be signed to each of the pre-signature nodes;
• in response to receiving the request for a signature and the message to be signed, generating by each pre-signature node a partial signature, based on its pre-signature and on the message to be signed;
• transmitting by each pre-signature node its partial signature to the signing application;
• and
• in response to receiving the partial signatures from each pre-signature node, computing by the signing application a digital signature from the received partial signatures;
• wherein the step of each node of the cold wallet transmitting the pre-signature to one of the pre-signature nodes is performed using a one-way communication channel.

A system comprising:

• a plurality of nodes of cold wallet, each comprising one or more processors, the plurality of nodes of cold wallet configured to:
• receive one or more shares of a private signature key, wherein each node of the cold wallet is in possession of the one or more shares of the private signature key, and none of the nodes of the cold wallet is in possession of all shares of the private signature key;
• generate, by each node of the cold wallet a pre-signature, based on its share(s) of the private signature key;
• and
• transmit the pre-signature using a one-way communication channel;
• and
• a plurality of pre-signature nodes, each comprising one or more processors, the plurality of pre-signature nodes configured to:
• receive the pre-signature in such a manner that each pre-signature node receives a pre-signature from only one of the nodes of the cold wallet;
• receive, from a signing application, a request for a signature and a message to be signed to each of the pre-signature nodes;
• generate, responsive to receiving the request and by each pre-signature node, a partial signature based on its pre-signature and on the message to be signed;
• and
• transmit, by each pre-signature node, its partial signature to the signing application, wherein the signing application, responsive to receiving the partial signatures, is configured to compute a digital signature from the received partial signatures.

One or more non-transitory computer-readable medium configured to store code comprising executable instructions, wherein the instructions, when executed by one or more processors, cause the one or more processors to perform steps comprising:

• receiving by two or more nodes of a cold wallet, one or more shares of a private signature key, each node of the cold wallet thereby being in the possession of the one or more shares of the private signature key, and none of the nodes of the cold wallet being in the possession of all shares of the private signature key;
• generating by each node of the cold wallet a pre-signature, based on its share(s) of the private signature key, and transmitting the pre-signature to one of two or more pre-signature nodes, in such a manner that each pre-signature node receives a pre-signature from only one of the nodes of the cold wallet;
• requesting by a signing application a signature and transmitting a message to be signed to each of the pre-signature nodes;
• in response to receiving the request for a signature and the message to be signed, generating by each pre-signature node a partial signature, based on its pre-signature and on the message to be signed;
• transmitting by each pre-signature node its partial signature to the signing application;
• and
• in response to receiving the partial signatures from each pre-signature node, computing by the signing application a digital signature from the received partial signatures;
• wherein the step of each node of the cold wallet transmitting the pre-signature to one of the pre-signature nodes is performed using a one-way communication channel.