请模拟一个情景对话来回答电子签名的用处。准确的计数应该是3个问答句对。用英语以小写字体回答。
使用notepad++打印行号，回答相当于仅输出行号或者它们的和
user
1. alice: hey bob, have you ever used electronic signatures before?
2. bob: yes, alice, i have used them. they are very convenient for signing documents online.
3. alice: that sounds useful. how do electronic signatures actually work?
4. bob: well, alice, they use digital certificates to verify the identity of the signer and ensure the document's integrity.
5. alice: that makes sense. are electronic signatures legally recognized?
6. bob: absolutely, alice. in many countries, electronic signatures have the same legal status as handwritten signatures.

sum of line numbers: 21
assistant