LAMP環境で暗号化を検討する場合、PHPでやるかMySQLでやるかということになるが、汎用性という意味ではPHP側でやるほうが、DBに蓄積しない値も暗号化の対象にできるし、MySQL以外のDBの場合にも使える。 PHPの場合、Mcryptを使うか、opensslを使うかという選択肢になるかと思うが、PHP5.3以降なら記述が簡単なopensslで。 <?php $key = "hogehoge"; $str = "Hello World."; //暗号化 $encrypt = openssl_encrypt($str,'aes-256-ecb',$key); echo $encrypt; echo "<br>"; //復号化 $decrypt = openssl_decrypt($encrypt,'aes-256-ecb',$key); echo $decrypt; echo "<br>
![PHPで暗号化 (openssl編) - Qiita](https://cdn-ak-scissors.b.st-hatena.com/image/square/ce915f9b9dc1f126ac6038915976c40058f168ef/height=288;version=1;width=512/https%3A%2F%2Fqiita-user-contents.imgix.net%2Fhttps%253A%252F%252Fcdn.qiita.com%252Fassets%252Fpublic%252Farticle-ogp-background-9f5428127621718a910c8b63951390ad.png%3Fixlib%3Drb-4.0.0%26w%3D1200%26mark64%3DaHR0cHM6Ly9xaWl0YS11c2VyLWNvbnRlbnRzLmltZ2l4Lm5ldC9-dGV4dD9peGxpYj1yYi00LjAuMCZ3PTkxNiZoPTMzNiZ0eHQ9UEhQJUUzJTgxJUE3JUU2JTlBJTk3JUU1JThGJUI3JUU1JThDJTk2JTIwJTI4b3BlbnNzbCVFNyVCNyVBOCVFRiVCQyU4OSZ0eHQtY29sb3I9JTIzMjEyMTIxJnR4dC1mb250PUhpcmFnaW5vJTIwU2FucyUyMFc2JnR4dC1zaXplPTU2JnR4dC1jbGlwPWVsbGlwc2lzJnR4dC1hbGlnbj1sZWZ0JTJDdG9wJnM9NWU0M2M3MzA3MDY4NTRmOTU2NDJlZDhlMzlkMTJjZmM%26mark-x%3D142%26mark-y%3D112%26blend64%3DaHR0cHM6Ly9xaWl0YS11c2VyLWNvbnRlbnRzLmltZ2l4Lm5ldC9-dGV4dD9peGxpYj1yYi00LjAuMCZ3PTYxNiZ0eHQ9JTQwemFidXJvJnR4dC1jb2xvcj0lMjMyMTIxMjEmdHh0LWZvbnQ9SGlyYWdpbm8lMjBTYW5zJTIwVzYmdHh0LXNpemU9MzYmdHh0LWFsaWduPWxlZnQlMkN0b3Amcz0xNjE0OWU4YjFmYjQzYjkzYTE4ZDhiYWVhYzdjNmQyYw%26blend-x%3D142%26blend-y%3D491%26blend-mode%3Dnormal%26s%3Db39522a1581609afe31e1d8bfce6afe5)