===== SHA256 =====

SHA-256 is a cryptographic (one-way) **hash function**, so there is no direct
way to decode it. The entire purpose of a cryptographic hash function is that
you can't undo it.

Hashing is a one way function (well, a mapping). It's irreversible, you apply
the secure hash algorithm and you cannot get the original string back. The most
you can do is to generate what's called "a collision", that is, finding a
different string that provides the same hash. Cryptographically secure hash
algorithms are designed to prevent the occurrence of collisions. You can attack
a secure hash by the use of a rainbow table, which you can counteract by
applying a salt to the hash before storing it.

Encrypting is a proper (two way) function. It's reversible, you can decrypt the
mangled string to get original string if you have the key.

Puede servir para guardar una password encriptada en b.d.

<code bash>
echo clave |sha256sum
</code>

<code>
a4011bda24f2f35c835acd50acafba77329b373df71d716a1a5c2f067e6a8e35  -
</code>