Is there a way to take any number, from say, 1 to 40000 and generate an 8 character hash?

I was thinking of using `base_convert`

but couldn’t figure out a way to force it to be an 8 character hash.

Any help would be appreciated!

Why don’t you just run `md5`

and take the first 8 characters?

Because you are wanting a hash, it doesn’t matter whether portions are discarded, but rather that the same input will produce the same hash.

```
$hash = substr(md5($num), 0, 8);
```

### Answer：

```
>>> math.exp(math.log(40000)/8)
3.7606030930863934
```

Therefore you need 4 digit-symbols to produce a 8-character hash from 40000:

```
sprintf("%08s", base_convert($n, 10, 4))
```

### Answer：

For php:

```
$seed = 'JvKnrQWPsThuJteNQAuH';
$hash = sha1(uniqid($seed . mt_rand(), true));
# To get a shorter version of the hash, just use substr
$hash = substr($hash, 0, 10);
```

### Answer：

there are many ways …

one example

```
$x = ?
$s = '';
for ($i=0;$i<8;++$i)
{
$s .= chr( $x%26 + ord('a') );
$x /= 26;
}
```

### Answer：

```
$hash = substr(hash("sha256",$num), 0, 8);
```

### Answer：

So you want to convert a 6 digit number into a 8 digit string reproducibly?

```
sprintf("%08d", $number);
```

Certainly a hash is not reversible – but without a salt / IV it might be a bit easy to hack. A better solution might be:

```
substr(sha1($number . $some_secret),0,8);
```

C.