How to set the hmacsha1 key to hex in PHP?

Question

I'm able to successfully get a HMAC SHA1 signature key using the following code: ``` echo hash_hmac('sha1','office:fred','AA381AC5E4298C23B3B3333333333333333333'); ``` which yields: ``` 5e50e6458b0cdc7ee534967d113a9deffe6740d0 ``` However, the place I am working with is expecting this instead: ``` 46abe81345b1da2f1a330bba3d6254e110cd9ad8 ``` I tried an online tool and it appears that the difference between the two is that the one the people I am working with are expecting a HEX type signature key. Is there something I need to add to my PHP in order to output the HEX type?

Accepted Answer

You'll need to convert the hexadecimal string to binary data before passing it into hash_hmac:

```
var_dump(hash_hmac("sha1", "office:fred", pack("H*", "AA381AC5E4298C23B3B3333333333333333333")));
```

Outputs `46abe81345b1da2f1a330bba3d6254e110cd9ad8` as expected.

How to set the hmacsha1 key to hex in PHP?

Solution

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