pdf.py 文件源码

def encrypt(self, user_pwd, owner_pwd = None, use_128bit = True):
        import time, random
        if owner_pwd == None:
            owner_pwd = user_pwd
        if use_128bit:
            V = 2
            rev = 3
            keylen = 128 / 8
        else:
            V = 1
            rev = 2
            keylen = 40 / 8
        # permit everything:
        P = -1
        O = ByteStringObject(_alg33(owner_pwd, user_pwd, rev, keylen))
        ID_1 = md5(repr(time.time())).digest()
        ID_2 = md5(repr(random.random())).digest()
        self._ID = ArrayObject((ByteStringObject(ID_1), ByteStringObject(ID_2)))
        if rev == 2:
            U, key = _alg34(user_pwd, O, P, ID_1)
        else:
            assert rev == 3
            U, key = _alg35(user_pwd, rev, keylen, O, P, ID_1, False)
        encrypt = DictionaryObject()
        encrypt[NameObject("/Filter")] = NameObject("/Standard")
        encrypt[NameObject("/V")] = NumberObject(V)
        if V == 2:
            encrypt[NameObject("/Length")] = NumberObject(keylen * 8)
        encrypt[NameObject("/R")] = NumberObject(rev)
        encrypt[NameObject("/O")] = ByteStringObject(O)
        encrypt[NameObject("/U")] = ByteStringObject(U)
        encrypt[NameObject("/P")] = NumberObject(P)
        self._encrypt = self._addObject(encrypt)
        self._encrypt_key = key

    ##
    # Writes the collection of pages added to this object out as a PDF file.
    # <p>
    # Stability: Added in v1.0, will exist for all v1.x releases.
    # @param stream An object to write the file to.  The object must support
    # the write method, and the tell method, similar to a file object.