Digital Multisignatures with Application to Cryptocurrencies, Blockchains, and IoT Devices

Digital signatures are asymmetric cryptographic schemes used to validate the authenticity and integrity of digital messages or documents. The signer uses their private key to generate a signature on a message. Then, this signature can be validated by any verifier who knows the signer’s corresponding public key. Sometimes a digital message might require signatures from a group of signers. The naïve method to achieve this goal is collecting distinct signatures from all signers. Multisignature schemes enable a group of signers to jointly generate a common signature that is more compact than the output from the mentioned naïve method. For some multi-signature schemes, verifiers are able to aggregate the signers’ public keys into one aggregated public key, as well. Then, signature verification can be done like a regular signature verification. This property is called key aggregation and is useful for use cases where public keys size matters (e.g. Blockchain and/or cryptocurrency). Multisignature might also be used in IoT applications with resource-constrained IoT devices. To design a multisignature scheme for such use cases, storage, memory, processing, and battery lifetime requirements of IoT devices must be considered.