Online numbers for receiving SMS
There are various approaches to authentication using request response systems, but modern on-demand authentication methods typically include one or more cryptographic protocols to prove that the authenticated user knows the password without having to share the password itself.
In authentication with request-response, the client application initially receives a random task - usually data of a certain type - from the server. For password-based response protection systems, the client system calculates the response by applying a cryptographic hash function to the call from the server in combination with the user's password. The application then sends the response, as well as the original request, back to the server.
When the server receives a response, it applies the same hash function to the request data in combination with its own copy of the user's password. If the resulting value and the response sent by the application match, there is a very high probability that the user sent the correct password.
While response authentication systems typically rely on cryptography to provide reliable user authentication, CAPTCHA (Turing's fully automated public test for transferring data to computers). The request-response system is an example of a non-cryptographic protocol for responding to a request-response, designed to differentiate people from robotic programs. CAPTCHA is used to prevent spam and automatically register new email accounts or websites.
How does checking response to request-response work
When a user tries to log into a system or network resource, the system server with a request-response creates a call, usually a random number, which is then sent to the client machine.
Client software uses a secret key or a key based on its password to encrypt request data using an encryption algorithm or a one-way hash function. Then it sends the result back to the network server.
The request-response authentication system performs the same cryptographic process on the problem, comparing its result with the response from the client. If these two values match, the authentication system can authenticate the client.
There are two types of questions to call: static and dynamic.
Static questions allow the user to select predefined questions from the bank or allow the user to create custom questions asked. The user then provides answers to the questions he has selected. For example, a static problem may be to indicate the name of the first pet, first car or teacher - the correct values will not change over time, and the user can specify the correct values as part of their account settings,
Dynamic questions are created by extracting publicly available data about the user that the person needs to know, for example, the previous address or the make and model of the previous car. The system presents random questions and answers to the user in which this data is used, from which the user must select the correct answer.
Authentication with response requests can protect against session replay attacks in which an attacker listens on previous messages and retransmits them later to obtain the same data as the original message. Challenge-response systems protect against repeated attacks because each challenge and response is unique. An attacker who controls the exchange of credentials, and then when trying to reuse the credentials, will not be able to gain access.
Some types of call response systems can help protect against attacks, especially when the request and response require some knowledge that the attacker does not have access to. For example, request and response values digitally signed by the endpoint using a private key, or which depend on any other data that was not compromised by the attacker, should protect the endpoint from attacks.
Used for authentication on demand
Typically, organizations use request and response authentication systems so that users can reload their own passwords, as well as for emergency access, allowing users to solve their problems and work faster, reducing the load on their help desks and saving money.