The electronic signature of the drawing is valid. An electronic signature shall be regarded as reliable if it meets the following conditions: 1. When the electronic signature production data is used for electronic signature, it belongs exclusively to the electronic signer; 2. When signing, the electronic signature production data is only controlled by the electronic signer; 3. Any changes to the electronic signature after signing can be found; Any changes to the content and form of the data message after signing can be found. , the parties can also choose to use electronic signatures that meet their agreed reliable conditions. Due to the diversity of electronic signature forms, its reliability, authenticity and stability may vary greatly due to the different technical schemes adopted, resulting in its legal effect not being at the same level. The principle of "functional equivalence" can solve this problem well, and there are three basic models: first, only electronic signatures that meet certain conditions have the same legal effect as traditional signatures; Secondly, based on the stability, reliability and authenticity of electronic signatures, different patterns and characteristics of electronic signatures have different legal effects; Third, the electronic signature that meets the corresponding requirements can have the same legal effect as the traditional signature, regardless of the specific technical scheme. Taking this as the basis to judge whether the electronic signature has legal effect, it reduces the unstable influence of the diversity of electronic technology on the effectiveness of electronic signature. The two basic functions of electronic signature are: 1. Identify the signer, and 2. Indicate the signer's approval of the content. Legally, technical neutrality is fully considered when defining electronic signature, and the provisions on electronic signature are extracted according to the basic functions of signature. It is considered that all electronic technical means that meet the basic functions of signature can be considered as electronic signature. From the definition of electronic signature and digital signature, we can see the difference between them: electronic signature is put forward from the legal point of view and is technology-neutral, and any electronic technical means that meets the basic functions of signature can be called electronic signature; Digital signature is put forward from a technical point of view, which requires the use of cryptographic technology. The main purpose is to confirm the source and integrity of the data unit.