Digital Certificate is the correct answer of this question.
Explanation:
Digital certificates are always for encryption and identification for transmitting public keys.The concept of digital certificate is a data structure used for linking an authenticated person to a public key. It is used to cryptographically attach public key rights to the organization that controls it.
<u>For example</u>:- Verisign, Entrust, etc.
An appendix to an electronic document that is used for authentication purposes.
A digital certificate's most frequent use is to confirm that an user sending a message is who he or she appears to be, and provide the recipient with the means to encode a response.
A right triangle can have sides that are all integers. A set of three integer values for the sides of a right triangle is called a Pythagorean triple. These three sides must satisfy the relationship that the sum of the squares of two of the sides is equal to the square of the hypotenuse.