base64_table = 'ghijklmnopqrstuvwxyz0123456789+/ABCDEFGHIJKLMNOPQRSTUVWXYZabcdef' def btoa():  # base64编码函数    s = input("input string to encode:\n")    n = len(s) % 3    x = ''    asc = []    for i in range(len(s)):        asc.append(ord(s[i]))  # 取各字符ascii值        x += '{:08b}'.format(asc[i])  # 将各字符ascii值转为二进制    if n:        x += '0' * 2 * (3 - n)  # 长度非3倍的结尾补零    i = 0    out = ''    while i < len(x):        out += base64_table[int(x[i:i + 6], 2)]        i += 6    if n:        out += '=' * (3 - n)  # 补上'='使编码后长度为4倍    print(out)  def atob():  # base64解码函数    s = input("input string to decode:\n")    b64 = []    x = ''    for i in range(len(s)):        if s[i] == '=':            b64.append(0)        else:            for j in range(64):                if (s[i] == base64_table[j]):                    b64.append(j)                    break        x += '{:06b}'.format(b64[i])     print(x)    i = 0    out = ''    while i < len(x):        if int(x[i:i + 8], 2):            out += chr(int(x[i:i + 8], 2))        i += 8    print(out)  def main():    m = input('Input 1/2 to encode/decode:\n')    if m == '1':        btoa()    elif m == '2':        atob()    else:        print('Error! Please restart the process!')  main()

# RC4from Crypto.Util.number import bytes_to_long, long_to_bytes key = "szv~"msg = "\x72\xA7\xE5\xB1\xBF\xD1\x3A\xC9\x7E\x5D\x83\xA8\x21\x4F\x70\x90"key = list(key)# KSAS = [i for i in range(256)]j = 0for i in range(256):    j = (j + S[i] + ord(key[i % len(key)])) % 256    S[i], S[j] = S[j], S[i]# PRGAi = 0j = 0keystream = []for k in range(len(msg)):    i = (i + 1) % 256    j = (j + S[i]) % 256    S[i], S[j] = S[j], S[i]    keystream.append(S[(S[i] + S[j]) % 256]) enc = "".join(map(chr, [(ord(msg[i]) ^ keystream[i]) for i in range(len(keystream))]))print(enc)

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