# Mutual Transport Layer Security (mTLS)

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Mutual TLS (mTLS) is a technique used to authenticate and encrypt messages sent between two [services](https://glossary.cncf.io/service/). 
Mutual TLS is the standard [Transport Layer Security](https://glossary.cncf.io/transport-layer-security/) (TLS) protocol but, 
instead of validating the identity of just one connection, both sides are validated.

## Problem it addresses

[Microservices](https://glossary.cncf.io/microservices-architecture/) communicate over a network and, 
just like your wifi network, communication in transit over that network can be hacked. 
mTLS ensures that no unauthorized party can listen in on or impersonate legitimate requests.

## How it helps

mTLS ensures that traffic is secure and trusted in both directions between a client and server, 
providing an additional layer of security for users who log in to a network or applications. 
It also verifies connections with client devices that do not follow a login process, such as Internet of Things (IoT) devices. 
Attacks like on-path attacks, spoofing attacks, credential stuffing, brute force attacks, etc. can be prevented by mTLS.

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- Canonical URL: https://glossary.cncf.io/mutual-transport-layer-security/
- Status: Completed
- Last modified March 27, 2024: ` [en] Update links to 'microservices' (#3009) ` ([693b72b](https://github.com/cncf/glossary/commit/693b72b1b49449570de53822cec27af98e73afa7))
- Source: https://github.com/cncf/glossary/blob/main/content/en/mutual-transport-layer-security.md
- License: [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/)