加密数字和字母的密码移位

def caesar_cipher(text, shift, encrypt=True):
    result = ""
    for char in text:
        if char.isalpha():
            shift_amount = shift % 26
            if not encrypt:
                shift_amount = -shift_amount
            new_char = chr((ord(char) - ord('A') + shift_amount) % 26 + ord('A'))
            result += new_char
        else:
            result += char
    return result

# 加密示例
plaintext = "HELLO"
shift = 3
ciphertext = caesar_cipher(plaintext, shift, encrypt=True)
print(f"Encrypted: {ciphertext}")

# 解密示例
decrypted_text = caesar_cipher(ciphertext, shift, encrypt=False)
print(f"Decrypted: {decrypted_text}")