Skip to content

PyCryptodome

Installation

1
pip3 install pycryptodome
  • Run self test
1
python3 -m Crypto.SelfTest

Usage

  • Generate random bytes
1
2
3
4
5
from Crypto.Random import get_random_bytes

# 產生 256 位元隨機金鑰（32 位元組 = 256 位元）
key = get_random_bytes(32)
print(key)
  • Use password to generate key (hash)
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
from Crypto.Protocol.KDF import PBKDF2

# 固定的 salt
salt = b'\xd0\x18\xa7QM\xd6\x9b\xebxu\xe4\xed\xa8\x83\xf6\xa3/\x01\x9c\x9e\x86n\xda;\x10EdD\xf7\x932\xcc'

# 密碼
password = 'my#password'

# 根據密碼與 salt 產生金鑰
key = PBKDF2(password, salt, dkLen=32)

AES CBC

  • Encrypt
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
from Crypto.Cipher import AES
from Crypto.Util.Padding import pad

key = b'A'*32 # change
plaintext = b'My secret data.'
cipher = AES.new(key, AES.MODE_CBC)
enc = cipher.encrypt(pad(plaintext, AES.block_size))

# iv: ciphter.iv (16 bytes)
# encrypted: enc
  • Decrypt
1
2
3
4
5
6
7
8
9
from Crypto.Cipher import AES
from Crypto.Util.Padding import unpad

enc = b'your encrypted data'
iv = b'your iv'
# 以金鑰搭配 CBC 模式與初始向量建立 cipher 物件
cipher = AES.new(key, AES.MODE_CBC, iv=iv)
# 解密後進行 unpadding
plaintext = unpad(cipher.decrypt(enc), AES.block_size)

References

Python 以 PyCryptodome 實作 AES 對稱式加密方法教學與範例

https://hackmd.io/@Not/Pbkdf2

https://stackoverflow.com/questions/30056762/rsa-encryption-and-decryption-in-python

https://pastebin.com/tfH13zpA