decrypts sqlite3 databases that are encrypted with System.Data.SQLite

decrypt_sqlite.py

def decryptSystemDataSQLite(file, password):
    """ Decrypts a sqlite3 database encrypted with System.Data.SQLite """
    """ 
    System.Data.SQLite has built-in encryption that uses the Windows 
    Cryptography API, which is cool when you are on Windows but if you aren't,
    you are shit outta luck working with these databases.
    
    PyCrypto to the rescue! It works on most platforms.  
    Thanks to dlitz for making this kick-ass easy to use crypto lib.

    For the original S.D.S code check out http://system.data.sqlite.org/index.html/artifact/e86de9c8c0008bb56fb04a49c9287c9440d4e8cd

    To the extent possible under law, @zuccaro has waived all copyright and 
    related or neighboring rights to decryptSystemDataSQLite. 
    """

    from Crypto.Hash import SHA 
    from Crypto.Cipher import ARC4
    from struct import unpack
    from tempfile import NamedTemporaryFile
    ret = None
    with open(file,'rb') as f:
        key = SHA.new(password).digest()[:16] #win crypto api seems to use 16b
        header = ARC4.new(key).decrypt(f.read(1024)) #preemptively read header
        if header[0:15] == 'SQLite format 3': #sanity check, proceed if valid
            declared_ps = unpack('>H',header[16:18])[0] #ushort_be @ 16
            if declared_ps == 1: #1 is a special page_size
                declared_ps = 65536 #it actually means 64k
            t = NamedTemporaryFile(delete=False,suffix='.sqlite')
            f.seek(0) # be kind rewind
            while True:
                block = f.read(declared_ps)
                if not block: #so pythonic
                    break  #gtfo
                t.write(ARC4.new(key).decrypt(block)) #reinitialize rc4 
            t.close() # close temp file
            ret = t.name # return temp file name
    return ret

Thank you very much for the code.
If not wrong the line 25 has to be changed to compare bytes.
if header[0:15] == b'SQLite format 3':