# Overview

Cryptography uses algorithms to decode and encode data. Cryptographic algorithms are designed to be difficult or nearly impossible to break.\
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Information secured with cryptography is incredibly hard for unauthorized parties to access. 

The sender and receiver of the information must have the right cryptographic key in order to encode and decode the data. 

Two main types of Cryptography:

{% tabs %}
{% tab title="Symmetric key cryptography" %}
A <mark style="color:yellow;">**single key system**</mark>: the same key is used to encode and decode data. \
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\&#xNAN;*This key must be kept secret, as anyone who has access to it can decode the data.*&#x20;
{% endtab %}

{% tab title="Asymmetric key cryptography" %}
Also known as public-key cryptography, asymmetric cryptography uses two different keys: a public key and a private key. \
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\&#xNAN;*The <mark style="color:purple;">**public key**</mark> can be shared with anyone, as it is used to encode the data.* \
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\&#xNAN;*The <mark style="color:red;">**private key**</mark> is kept secret and is used to decode the data.*&#x20;
{% endtab %}
{% endtabs %}

{% hint style="info" %}
A key can be a number, a word, or a phrase.
{% endhint %}