secrets
— 生成用于管理机密的安全随机数
¶
3.6 版新增。
源代码： Lib/secrets.py
secrets
module is used for generating cryptographically strong random numbers suitable for managing data such as passwords, account authentication, security tokens, and related secrets.
In particularly,
secrets
should be used in preference to the default pseudo-random number generator in the
random
module, which is designed for modelling and simulation, not security or cryptography.
另请参阅
secrets
module provides access to the most secure source of randomness that your operating system provides.
secrets.
SystemRandom
¶
A class for generating random numbers using the highest-quality sources provided by the operating system. See
random.SystemRandom
for additional details.
secrets.
choice
(
sequence
)
¶
Return a randomly-chosen element from a non-empty sequence.
secrets.
randbelow
(
n
)
¶
Return a random int in the range [0, n ).
secrets.
randbits
(
k
)
¶
Return an int with k random bits.
secrets
module provides functions for generating secure tokens, suitable for applications such as password resets, hard-to-guess URLs, and similar.
secrets.
token_bytes
(
[
nbytes=None
]
)
¶
Return a random byte string containing
nbytes
number of bytes. If
nbytes
is
None
or not supplied, a reasonable default is used.
>>> token_bytes(16)
b'\xebr\x17D*t\xae\xd4\xe3S\xb6\xe2\xebP1\x8b'
secrets.
token_hex
(
[
nbytes=None
]
)
¶
Return a random text string, in hexadecimal. The string has
nbytes
random bytes, each byte converted to two hex digits. If
nbytes
is
None
or not supplied, a reasonable default is used.
>>> token_hex(16)
'f9bf78b9a18ce6d46a0cd2b0b86df9da'
secrets.
token_urlsafe
(
[
nbytes=None
]
)
¶
Return a random URL-safe text string, containing
nbytes
random bytes. The text is Base64 encoded, so on average each byte results in approximately 1.3 characters. If
nbytes
is
None
or not supplied, a reasonable default is used.
>>> token_urlsafe(16)
'Drmhze6EPcv0fN_81Bj-nA'
To be secure against
brute-force attacks
, tokens need to have sufficient randomness. Unfortunately, what is considered sufficient will necessarily increase as computers get more powerful and able to make more guesses in a shorter period. As of 2015, it is believed that 32 bytes (256 bits) of randomness is sufficient for the typical use-case expected for the
secrets
模块。
For those who want to manage their own token length, you can explicitly specify how much randomness is used for tokens by giving an
int
argument to the various
token_*
functions. That argument is taken as the number of bytes of randomness to use.
Otherwise, if no argument is provided, or if the argument is
None
，
token_*
functions will use a reasonable default instead.
注意
That default is subject to change at any time, including during maintenance releases.
secrets.
compare_digest
(
a
,
b
)
¶
返回
True
if strings
a
and
b
are equal, otherwise
False
, in such a way as to reduce the risk of
timing attacks
。见
hmac.compare_digest()
for additional details.
This section shows recipes and best practices for using
secrets
to manage a basic level of security.
Generate an eight-character alphanumeric password:
import string
alphabet = string.ascii_letters + string.digits
password = ''.join(choice(alphabet) for i in range(8))
注意
Applications should not store passwords in a recoverable format , whether plain text or encrypted. They should be salted and hashed using a cryptographically-strong one-way (irreversible) hash function.
Generate a ten-character alphanumeric password with at least one lowercase character, at least one uppercase character, and at least three digits:
import string
alphabet = string.ascii_letters + string.digits
while True:
password = ''.join(choice(alphabet) for i in range(10))
if (any(c.islower() for c in password)
and any(c.isupper() for c in password)
and sum(c.isdigit() for c in password) >= 3):
break
Generate an XKCD-style passphrase :
# On standard Linux systems, use a convenient dictionary file.
# Other platforms may need to provide their own word-list.
with open('/usr/share/dict/words') as f:
words = [word.strip() for word in f]
password = ' '.join(choice(words) for i in range(4))
Generate a hard-to-guess temporary URL containing a security token suitable for password recovery applications:
url = 'https://mydomain.com/reset=' + token_urlsafe()