Richard写的文本加密算法

def sts(str1):
    b=""
    a=stn(str1)
    x=1
    for i in str(a):
        if x==1:
            b+=i
            x=0
        elif i=="0":
            b+="1"
        elif i=="1":
            b+="0"
        else:
            b+="2"
            x=1
    str2=nts(b)
    return str2

def nts(a):
    str1=""
    ls=[]
    for k in str(a):
        if k=="2":
            ls.append(int(str1))
            str1=""
        else:
            str1+=k
    b=""
    for i in ls:
        b+=chr(num2t10(i))
    return b

def num2t10(num):
    num=str(num)
    num1=""
    num2=0
    for i in range(len(num)):
        num1+=num[-i-1]
    for j in range(len(num1)):
        num2+=int(num1[j])*(2**j)
    return num2

def stn(str1):
    a=""
    for i in str1:
        a+=str((num10t2(ord(i))))
        a+="2"
    return int(a)

def num10t2(num):
    str1=""
    str2=""
    while num>0:
        c=num%2
        str1+=str(c)
        num=int(num/2)
    for i in range(len(str1)):
        str2+=str1[-i-1]
    return int(str2)

def sts(origin): # OPTIMIZE
    """加密/解密主函数。
    
    由于实质上是异或加密，所以加密和解密是同一个算法。
    """
    resultEncoded = ""
    originEncoded = str(stn(origin)) # 第一步是调用stn()，先看stn()的定义
    isHighestBit = True
    for bit in originEncoded: # 这个循环用来进行迫真按位运算
        if isHighestBit:
            resultEncoded += bit
            isHighestBit = False
        elif bit == '0':
            resultEncoded += '1'
        elif bit == '1':
            resultEncoded += '0'
        else:
            resultEncoded += '2'
            isHighestBit = True
    return nts(resultEncoded) # 最后调用nts()，看nts()的定义

def stn(string):
    """把每个字符的字符编码转换成二进制数，然后每个数后用'2'连接。
    
    如："ABC" → "100000121000010210000112"
    """
    # 实际上，一开始采用的加密算法是这个函数；
    # 由于密文的体积太大，才有了现在的版本。
    encoded = ""
    for char in string:
        encoded += str(num10t2(ord(char))); # 对char的代码点调用了num10t2()
        encoded += '2'
    return int(encoded) # ???: 为什么要转成int？？？

def num10t2(decimal):
    """把正整数用二进制表示。
    """
    reversedBinary = ""
    binary = ""
    while decimal > 0:
        reversedBinary += str(decimal % 2) # OPTIMIZE: 建议改成：decimal & 1
        # OPTIMIZE: 为什么要事后手动倒转字符串，而不是直接把这里新增的字符拼接在字符串的开头？
        decimal = int(decimal / 2) # OPTIMIZE: decimal >>= 1 它不香吗？
    for i in range(len(reversedBinary)):
        binary += reversedBinary[len(reversedBinary) - i - 1]
    return int(binary) # ???: 为什么要转成int？？？

def nts(encoded):
    """解码“encode()”生成的密文。
    """
    binaryBuffer = "" # 存储一个二进制数，遇到'2'就拿走使用并清空
    binaryList = []
    for bit in str(encoded):
        if bit == '2':
            binaryList.append(int(binaryBuffer)) # HACK: 为什么要转成int？？？
            binaryBuffer = ""
        else:
            binaryBuffer += bit
    decoded = ""
    for binary in binaryList:
        decoded += chr(num2t10(binary)) # 对代码点的二进制调用了num2t10()
    return decoded

def num2t10(binary):
    """解析二进制数。
    """
    # OPTIMIZE
    # 这算法看得我人都傻了
    binary = str(binary)
    reversedBinary = ""
    decimal = 0
    for i in range(len(binary)):
        reversedBinary += binary[len(binary) - i - 1]
    for i in range(len(reversedBinary)):
        decimal += int(reversedBinary[i]) * pow(2, i) # 1 << i 它不香吗？
        # 就算要乘方，** 运算符不知道？？
    return decimal

def sts(string):
    out = ""
    for char in string:
        codePoint = ord(char)
        shifter = -1
        temp = codePoint
        while temp & -2:
            temp >>= 1
            shifter <<= 1
        out += chr(codePoint ^ ~shifter)
    return out

def fromBin(bin):
    assert isinstance(bin, str) # 永远不要把二进制数转换成int！！
    dec = 0
    for i in bin:
        dec <<= 1
        if i == "1":
            dec |= 1
    return dec

def toBin(dec):
    assert isinstance(dec, int)
    assert dec > 0
    bin = ""
    while dec:
        bin = str(dec & 1) + bin # 把新的数位追加到bin的开头
        dec >>= 1
    return bin