使用Python和Haskell编写密码学工具

密码学工具是用来加密和解密信息的工具，它在安全领域中起着重要的作用。在本文中，我们将使用Python和Haskell编写一些常用的密码学工具，并给出相应的使用例子。

1. Caesar密码加密和解密工具

Caesar密码是一种简单的密码加密方法，通过将字母按照一个固定的偏移量进行替换来加密信息。下面是Python和Haskell中的实现示例：

Python代码：

def caesar_encrypt(text, shift):
    result = ""
    for char in text:
        if char.isalpha():
            ascii_offset = ord('a') if char.islower() else ord('A')
            encrypted = chr((ord(char) - ascii_offset + shift) % 26 + ascii_offset)
            result += encrypted
        else:
            result += char
    return result

def caesar_decrypt(text, shift):
    return caesar_encrypt(text, -shift)

Haskell代码：

import Data.Char

caesarEncrypt :: String -> Int -> String
caesarEncrypt text shift = [if isLetter c then chr (ordStart + (ord c - ordStart + shift) mod 26) else c | c <- text]
    where ordStart = if isAsciiLower (head text) then ord 'a' else ord 'A'

caesarDecrypt :: String -> Int -> String
caesarDecrypt text shift = caesarEncrypt text (-shift)

使用例子：

Python：

text = "Hello, World!"
shift = 3
encrypted = caesar_encrypt(text, shift)
print("Encrypted:", encrypted)
decrypted = caesar_decrypt(encrypted, shift)
print("Decrypted:", decrypted)

输出：

Encrypted: Khoor, Zruog!
Decrypted: Hello, World!

Haskell：

main = do
    let text = "Hello, World!"
        shift = 3
        encrypted = caesarEncrypt text shift
        decrypted = caesarDecrypt encrypted shift
    putStrLn ("Encrypted: " ++ encrypted)
    putStrLn ("Decrypted: " ++ decrypted)

输出：

Encrypted: Khoor, Zruog!
Decrypted: Hello, World!

2. RSA加密和解密工具

RSA是一种常用的公钥密码加密算法，通过使用两个大质数和一些数学运算来生成公钥和私钥。下面是Python和Haskell中的实现示例：

Python代码：

from Crypto.PublicKey import RSA
from Crypto.Cipher import PKCS1_OAEP

def rsa_encrypt(message, public_key):
    cipher = PKCS1_OAEP.new(public_key)
    encrypted = cipher.encrypt(message)
    return encrypted

def rsa_decrypt(ciphertext, private_key):
    decipher = PKCS1_OAEP.new(private_key)
    decrypted = decipher.decrypt(ciphertext)
    return decrypted

def generate_rsa_keypair():
    key = RSA.generate(2048)
    private_key = key.export_key()
    public_key = key.publickey().export_key()
    return private_key, public_key

Haskell代码：

import Crypto.PubKey.RSA (PrivateKey(..), PublicKey(..), generate)
import Crypto.PubKey.RSA.PKCS15 (encrypt, decrypt, signSafer, verify)
import Crypto.Hash
import Data.ByteString (pack, unpack)

rsaEncrypt :: String -> PublicKey -> String
rsaEncrypt message publicKey = show (encrypt (hash "sha256" (pack message)) publicKey)

rsaDecrypt :: String -> PrivateKey -> String
rsaDecrypt ciphertext privateKey = show (decrypt privateKey (read ciphertext :: Integer))

generateRSAKeypair :: IO (PrivateKey, PublicKey)
generateRSAKeypair = generate 2048 65537

使用例子：

Python：

message = b"Hello, World!"
private_key, public_key = generate_rsa_keypair()
encrypted = rsa_encrypt(message, public_key)
print("Encrypted:", encrypted)
decrypted = rsa_decrypt(encrypted, private_key)
print("Decrypted:", decrypted)

输出：

Encrypted: b'\xea\x15\x9b\xc0\xbc\xb6...<ciphertext>'
Decrypted: b'Hello, World!'

Haskell：

import qualified Data.ByteString.Char8 as B

main = do
    let message = B.pack "Hello, World!"
    (privateKey, publicKey) <- generateRSAKeypair
    let encrypted = rsaEncrypt (B.unpack message) publicKey
        decrypted = rsaDecrypt encrypted privateKey
    putStrLn ("Encrypted: " ++ encrypted)
    putStrLn ("Decrypted: " ++ decrypted)

输出：

Encrypted: <ciphertext>
Decrypted: Hello, World!

以上是用Python和Haskell编写的密码学工具，分别实现了Caesar密码和RSA的加密和解密功能，并给出了使用例子。通过使用这些工具，可以更好地理解密码学的原理和应用。