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<h2>
<a href="index.html"><code>~</code></a>
</h2>
<h1>
<a
id="user-content-real-world-crypto-101"
class="anchor"
aria-hidden="true"
tabindex="-1"
href="#real-world-crypto-101"
><span aria-hidden="true" class="octicon octicon-link"></span></a
>Real World Crypto 101
</h1>
<p>
My notes when reading
<a
href="https://www.manning.com/books/real-world-cryptography"
rel="nofollow"
>Real-World Cryptography</a
>
</p>
<p><strong>Hash</strong> function convert from input to digest:</p>
<ul>
<li>Pre-image resistance: Given digest, can not find input</li>
<li>
Second pre-image resistance: Given input, digest, can not find another
input produce same digest. Small change to input make digest big change.
</li>
<li>Collision resistance: Can not find 2 input produce same digest.</li>
</ul>
<p>
<strong>MAC</strong> aka Message Authentication Code produce from key,
message to authentication tag. <strong>HMAC</strong> is MAC using hash.
</p>
<ul>
<li>A send B message with MAC (generate from message and A key).</li>
<li>
B double check message with MAC (generate from receive message and B
key).
</li>
<li>A and B use same key.</li>
</ul>
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Feel free to ask me via
<a href="mailto:hauvipapro+posts@gmail.com">email</a> or
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<a href="https://git.sr.ht/~youngyoshie/posts-go">sourcehut</a>
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