New York Certification of Signature (Attorney or Party) is a document signed and notarized by an individual attesting to the authenticity of their signature. This document is typically used to verify the identity of a person who is signing a legal document or other document requiring authentication. There are two types of New York Certification of Signature: Attorney Certification of Signature and Party Certification of Signature. In an Attorney Certification of Signature, the document is signed by a licensed attorney and notarized by a Notary Public to confirm the identity and signature of the signer. This type of certification is most often used in commercial transactions and other legal matters. At a party Certification of Signature, the document is signed and notarized by the party themselves, thereby verifying the authenticity of their signature. This type of certification is most often used in residential transactions, such as real estate or loan agreements.