Postgresql hmac-sha1 signature differs from python signature

Question

Postgres:

Code:

SELECT encode(
    hmac(
        E'PUT\n\n1\n1408355972\nx-amz-acl:bucket-owner-full-control\n/1/1', 
        '1sf235123',
        'sha1'
    ),
    'base64'
);

Result: "h9wRL15mXgwRxXjqLqhbYbnfJ7I="

Python 3

Code:

base64.encodestring(
    hmac.new(
        'PUT\n\n1\n1408355972\nx-amz-acl:bucket-owner-full-control\n/1/1'.encode(),
        '1sf235123'.encode(),
        sha1
    ).digest()
)

Result: "CrU1V93ggf3QE0ovq686ir/i1ss=\n"

I want to signed s3 upload request in postgres, but I can't get the right signature, I have tried a whole day T_T.

Can someone give me a help??? Thanks a lot.

Clodoaldo Neto · Accepted Answer · 2014-08-18 10:32:22Z

2

You are swapping the two first hmac parameters in Python. The hmac constructor takes the secret first

>>> base64.encodestring(
...     hmac.new(
...         '1sf235123'.encode(),
...         'PUT\n\n1\n1408355972\nx-amz-acl:bucket-owner-full-control\n/1/1'.encode(),
...         sha1
...     ).digest()
... )
b'h9wRL15mXgwRxXjqLqhbYbnfJ7I=\n'

answered Aug 18, 2014 at 10:32

Clodoaldo Neto

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1 Comment

Zhou Over a year ago

Thanks, I am thoughtless.

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