rc4 对称加密，使用 python 和 js 实现

rc4.js

function rc4(data, key) {

	var box = Array(256)
	for (var i = 0; i < 256; i++) {
		box[i] = i
	}

	var x = 0
	for (var i = 0; i < 256; i++) {
		x = (x + box[i] + key.charCodeAt(i % key.length)) % 256
		var temp = box[i]
		box[i] = box[x]
		box[x] = temp
	}


	var x = 0
	var y = 0
	var out = []
	for (var i = 0; i < data.length; i++)
	{
		var code = data.charCodeAt(i)

		var x = (x + 1) % 256
		var y = (y + box[x]) % 256
		var temp = box[x]
		box[x] = box[y]
		box[y] = temp

		var k = (box[x] + box[y]) % 256

		out.push(String.fromCharCode(code ^ box[k]))
	}
	return out.join('')
}


key = 'mysecret'

a = rc4('hello world!', key)
console.log(a)

b = rc4(a, key)
console.log(b)


// include >> https://raw.githubusercontent.com/dankogai/js-base64/master/base64.js
// Base64.encode(a)

rc4.py

def rc4(data, key):
    """RC4 algorithm"""

    key = [ord(c) for c in key]  # or `key = key.encode()` for python3

    x = 0
    box = list(range(256))
    for i in range(256):
        x = (x + int(box[i]) + int(key[i % len(key)])) % 256
        box[i], box[x] = box[x], box[i]

    x = y = 0
    out = []
    for char in data:
        code = ord(char)
        x = (x + 1) % 256
        y = (y + box[x]) % 256
        box[x], box[y] = box[y], box[x]
        k = (box[x] + box[y]) % 256
        out.append(chr(code ^ box[k]))

    return ''.join(out)


key = 'mysecret'

a = rc4("hello world!", key)
print(a)

b = rc4(a, key)
print(b)


import base64
print(base64.b64encode(a.encode()))