[racket] string->bytes/locale on an HMAC-SHA1 hash returns error

Having issues with mailing list.  Trying again:

I've gotten a bit of help in #racket on freenode so far, but I'm still
facing a problem with this.

In Racket, I expect that this will get me a SHA1 hash (as bytes) of a
string, using a key:

(require web-server/stuffers/hmac-sha1
            net/base64)

(define (str-to-hash private-key str)
   (base64-encode (HMAC-SHA1 (string->bytes/utf-8 private-key)
                                                (string->bytes/utf-8 str))))

And let's convert the bytes to a string of hex:

(apply string-append (map (lambda (x) (number->string x 16)) (bytes->list
(str-to-hash "foo" "bar"))))

This gives me:

"527254735747455846553273314a316d546c316a2f63694f2b31453dda"

In Python, doing what I assume to be the same thing:

import hmac
from hashlib import sha1

hmac.new('foo', 'bar', sha1).hexdigest()

Returns something completely different:

'46b4ec586117154dacd49d664e5d63fdc88efb51'

Does anyone have any idea what's going on here?

On Sun, May 13, 2012 at 9:01 PM, Shawn Smith <shawn.p.smith at gmail.com>wrote:

> I've gotten a bit of help in #racket on freenode so far, but I'm still
> facing a problem with this.
>
> In Racket, I expect that this will get me a SHA1 hash (as bytes) of a
> string, using a key:
>
> (require web-server/stuffers/hmac-sha1
>             net/base64)
>
> (define (str-to-hash private-key str)
>    (base64-encode (HMAC-SHA1 (string->bytes/utf-8 private-key)
>                                                 (string->bytes/utf-8
> str))))
>
> And let's convert the bytes to a string of hex:
>
> (apply string-append (map (lambda (x) (number->string x 16)) (bytes->list
> (str-to-hash "foo" "bar"))))
>
> This gives me:
>
> "527254735747455846553273314a316d546c316a2f63694f2b31453dda"
>
> In Python, doing what I assume to be the same thing:
>
> import hmac
> from hashlib import sha1
>
> hmac.new('foo', 'bar', sha1).hexdigest()
>
> Returns something completely different:
>
> '46b4ec586117154dacd49d664e5d63fdc88efb51'
>
> Does anyone have any idea what's going on here?
>
> Shawn
>
> On Sun, May 13, 2012 at 7:18 PM, Shawn Smith <shawn.p.smith at gmail.com>wrote:
>
>> Hi,
>>
>> I'm trying to generate a SHA1 hash using a private key and a given
>> string, like so:
>>
>> (define a-hash (HMAC-SHA1 (string->bytes/locale "foo")
>> (string->bytes/locale "bar")))
>>
>> This returns bytes, but when I try to turn those bytes into a string with:
>>
>> (bytes->string/locale a-hash)
>>
>> I get:
>>
>> bytes->string/locale: string is not a well-formed UTF-8 encoding:
>> #"F\264\354Xa\27\25M\254\324\235fN]c\375\310\216\373Q"
>>
>> As I have no clue how to diagnose this, I'd appreciate any suggestions or
>> help.
>>
>> Thanks,
>> Shawn
>>
>
>
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