# `md5`

_Message Digest hash_

```syntax
md5 x    md5[x]
```

Where `x` is a string, returns as a bytestream its [MD5 (Message-Digest algorithm 5)](https://en.wikipedia.org/wiki/MD5) hash.
```q
q)md5 "this is a not so secret message"
0x6cf192c1938b79012c323fa30e62787e
```

MD5 is a widely used, Internet standard (RFC 1321), hash function that computes a 128-bit hash, commonly used to check the integrity of files. It is not recommended for serious cryptographic protection, for which strong hashes should be used.


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[Strings](../basics/by-topic.md#strings)