I am getting inconsistent behavior when getting an md5 hexdigest on a json structure that's converted to a string.
Am I doing something wrong here?

    import json
    import hashlib

    data = '''{"key1":"value1","key2":"value2"}'''

    print(hashlib.md5(data.encode()).hexdigest())
    jsonData = json.loads(data)
    print(hashlib.md5(str(jsonData).encode()).hexdigest())
    print(hashlib.md5(str(jsonData).encode()).hexdigest())

When I run this code everything seems just fine at a first glance. However, when it is run again I get different md5 checksums.
The first md5 checksum on the data string seems consistent every time.
The two last md5 checksums never seems to contradict each other during the same run, but between each run I often get different values.
Here are some outputs I'm getting:

ff45cc3835165307ef414c23ca2c6f67
423b2b4d92c0947e3d99d207c7c06175
423b2b4d92c0947e3d99d207c7c06175

ff45cc3835165307ef414c23ca2c6f67
101d66cd2878eacf47c618cea6862125
101d66cd2878eacf47c618cea6862125

ff45cc3835165307ef414c23ca2c6f67
423b2b4d92c0947e3d99d207c7c06175
423b2b4d92c0947e3d99d207c7c06175

ff45cc3835165307ef414c23ca2c6f67
101d66cd2878eacf47c618cea6862125
101d66cd2878eacf47c618cea6862125


(If it makes any difference, I'm running on Windows XP SP3)

The order in which elements are produced when iterating a dictionary is not fixed.  In python3.3 it is intentionally perturbed by a randomized seed at interpreter startup by default.

Actually, that’s not the point here, the code has a deeper flaw.

You’re computing hashlib.md5() on `data.encode()` and `str(jsonData).encode()`. Did you have a look how they look like?

>>> data.encode()
b'{"key1":"value1","key2":"value2"}'
[71875 refs]
>>> str(jsonData).encode()
b"{'key1': 'value1', 'key2': 'value2'}"

`str(jsonData)` doesn’t return JSON because it’s a simple dict():

>>> type(jsonData)
<class 'dict'>

If you wanted to have JSON again, you’d have to use `json.dumps()`:

>>> json.dumps(jsonData)
'{"key1": "value1", "key2": "value2"}'

HOWEVER: This string _also_ differs from yours due to additional whitespace, ie. the sum would differ again.

Additionally, as David pointed out, you can’t rely on the order of the dict. json.dump() could just as well return `'{"key2": "value2", "key1": "value1"}'`.

Yes, you are quite right.
Somewhere in the back of my head I had a feeling I should understand what was happening, hence my comment "Am I doing something wrong here?".
I just couldn't see it. 

Thank you.