Google App Engine开发服务器中的PyCrypto“ImportError：can not import name blockalgo”

我有一个使用PyCrypto加密字符串的函数。当我在单元测试中调用该函数时，一切正常。在生产环境中，它也可以正常工作。但是，在GAE开发服务器上调用该函数时，会引发错误：ImportError：无法导入名称blockalgo。我在Windows 7（64位）和Mac OS 10.5上测试了它。两者都导致相同的错误。我使用Python 2.7的Google App Engine。可能是什么问题？

I have a function which encrypts a string with AES using PyCrypto. When I call that function in my unit tests, everything works fine. On the production environment, it works fine as well. However, when the function is called on the GAE development server, an error is thrown: "ImportError: cannot import name blockalgo". I tested it on Windows 7 (64 bit) and Mac OS 10.5. Both resulted in the same error. I'm using Google App Engine with Python 2.7. What could be the problem?

app.yaml

application: xxx
version: 6
runtime: python27
api_version: 1
threadsafe: true

libraries:
- name: django
  version: "1.2"
- name: webapp2
  version: "2.3"
- name: jinja2
  version: "2.6"
- name: pycrypto
  version: "2.3"
- name: PIL
  version: "1.1.7"

builtins:
- appstats: on
- remote_api: on

inbound_services:
- mail
- warmup

加密函数：

Encryption function:

def encrypt(plaintext):
    from Crypto.Cipher import AES
    import hashlib

    password = 'xxx'
    key = hashlib.sha256(password).digest()

    mode = AES.MODE_ECB
    encryptor = AES.new(key, mode)

    BLOCK_SIZE = 16
    PADDING = '{'
    pad = lambda s: s + (BLOCK_SIZE - len(s) % BLOCK_SIZE) * PADDING
    EncodeAES = lambda c, s: b58encode(c.encrypt(pad(s)))

    encrypted = EncodeAES(encryptor, plaintext)

    if len(encrypted) < 22:
        for i in range (len(encrypted), 22):
            encrypted += "_"
    return encrypted