signer

Signer is a noun formed from the verb sign. In ordinary use, a signer is a person who signs a document—such as a contract, lease, or petition—thereby indicating consent, authorization, or acknowledgment. In many legal and business contexts, the person who signs is called the signer, while the group of people who have signed may be described as signatories; the terms overlap but have distinct nuance regarding action versus status.

In information security, a signer creates a digital signature with a private key. The signature can be verified by others using the signer's public key and a digital certificate. Digital signatures provide authentication, data integrity, and non-repudiation, and they are commonly implemented via public-key cryptography and standards such as RSA or ECDSA.

In distributed systems and blockchain, a signer or signers are authorities authorized to approve and sign transactions, blocks, or proposals. Multi-signature schemes require approvals from several signers before an action is valid.

Other uses: The term signer can also describe a person who uses sign language; such a person is commonly referred to as a signer, especially in contexts about Deaf communities or instructional materials.

See also: signatory, signature, digital signature, PKI, non-repudiation, sign language.