A more thorough explanation:

A private signature is a person's name or mark written by that person or at their direction. It is used to authenticate a document and can be any symbol made or adopted with the intention of verifying the signer's identity. Private signatures can take different forms, including:

• Digital signature: A secure, digital code attached to an electronically transmitted message that uniquely identifies and authenticates the sender. For example, when you click on a "place order" button on a retailer's website, you are generating a digital signature.
• Electronic signature: An electronic symbol, sound, or process that is either attached to or logically associated with a document and executed or adopted by a person with the intent to sign the document. For instance, a typed name at the end of an email or a digital image of a handwritten signature are both examples of electronic signatures.
• Facsimile signature: A signature that has been prepared and reproduced by mechanical or photographic means. It can also refer to a signature on a document that has been transmitted by a fax machine.
• Private signature: A signature made on a document, such as a will, that has not been witnessed or notarized.

It is important to note that an unauthorized signature, which includes a forgery, is not a private signature. Private signatures are intended to be used by the signer or someone acting on their behalf, while unauthorized signatures are made without actual, implied, or apparent authority.

For example, when you sign a contract using a digital signature, you are creating a private signature that verifies your identity and intent to sign the document. On the other hand, if someone forges your signature on a check, that is an unauthorized signature because it was made without your permission or authority.