<p><a href="https://stackexchange.com/users/1787030">
<img src="https://stackexchange.com/users/flair/1787030.png" width="208" height="58" alt="profile for swish on Stack Exchange, a network of free, community-driven Q&amp;A sites" title="profile for swish on Stack Exchange, a network of free, community-driven Q&amp;A sites">
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<p><img src="https://i.stack.imgur.com/dHbMO.png" alt="enter image description here"></p>

<p><a href="http://www.matasano.com/articles/crypto-challenges/" rel="nofollow noreferrer">You Should Do The Matasano Crypto Challenges</a>.
I did and they are awesome.</p>

swish