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JavaScript DHTML/Security/RSA Encoding - История изменений
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История изменений этой страницы в вики
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в 09:59, 26 мая 2010
2010-05-26T09:59:55Z
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2010-05-26T07:27:15Z
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<p><b>Новая страница</b></p><div>==RSA Encoding in JavaScript==<br />
<br />
<br />
<br />
<br />
<br />
<!-- start source code --><br />
<br />
<source lang="html4strict"><br />
<html><br />
<head><br />
<!--<br />
CryptoMX Tools<br />
Copyright (C) 2004 - 2006 Derek Buitehuis<br />
This program is free software; you can redistribute it and/or<br />
modify it under the terms of the GNU General Public License<br />
as published by the Free Software Foundation; either version 2<br />
of the License, or (at your option) any later version.<br />
This program is distributed in the hope that it will be useful,<br />
but WITHOUT ANY WARRANTY; without even the implied warranty of<br />
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the<br />
GNU General Public License for more details.<br />
You should have received a copy of the GNU General Public License<br />
along with this program; if not, write to the Free Software<br />
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.<br />
--><br />
<title>RSA Encoding</title><br />
</head><br />
<body><br />
<script language="JavaScript"><!--<br />
var dg=""<br />
function makeArray(n) {<br />
for (var i=1; i<=n; i++) {<br />
this[i]=0<br />
}<br />
return this<br />
}<br />
function rc4(key, text) {<br />
var i, x, y, t, x2;<br />
status("rc4")<br />
s=makeArray(0);<br />
for (i=0; i<256; i++) {<br />
s[i]=i<br />
}<br />
y=0<br />
for (x=0; x<256; x++) {<br />
y=(key.charCodeAt(x % key.length) + s[x] + y) % 256<br />
t=s[x]; s[x]=s[y]; s[y]=t<br />
}<br />
x=0; y=0;<br />
var z=""<br />
for (x=0; x<text.length; x++) {<br />
x2=x % 256<br />
y=( s[x2] + y) % 256<br />
t=s[x2]; s[x2]=s[y]; s[y]=t<br />
z+= String.fromCharCode((text.charCodeAt(x) ^ s[(s[x2] + s[y]) % 256]))<br />
}<br />
return z<br />
}<br />
function badd(a,b) { // binary add<br />
var r=""<br />
var c=0<br />
while(a || b) {<br />
c=chop(a)+chop(b)+c<br />
a=a.slice(0,-1); b=b.slice(0,-1)<br />
if(c & 1) {<br />
r="1"+r<br />
} else {<br />
r="0"+r<br />
}<br />
c>>=1<br />
}<br />
if(c) {r="1"+r}<br />
return r<br />
}<br />
function chop(a) {<br />
if(a.length) {<br />
return parseInt(a.charAt(a.length-1))<br />
} else {<br />
return 0<br />
}<br />
}<br />
function bsub(a,b) { // binary subtract<br />
var r=""<br />
var c=0<br />
while(a) {<br />
c=chop(a)-chop(b)-c<br />
a=a.slice(0,-1); b=b.slice(0,-1)<br />
if(c==0) {<br />
r="0"+r<br />
}<br />
if(c == 1) {<br />
r="1"+r<br />
c=0<br />
}<br />
if(c == -1) {<br />
r="1"+r<br />
c=1<br />
}<br />
if(c==-2) {<br />
r="0"+r<br />
c=1<br />
}<br />
}<br />
if(b || c) {return ""}<br />
return bnorm(r)<br />
}<br />
function bnorm(r) { // trim off leading 0s<br />
var i=r.indexOf("1")<br />
if(i == -1) {<br />
return "0"<br />
} else {<br />
return r.substr(i)<br />
}<br />
}<br />
function bmul(a,b) { // binary multiply<br />
var r=""; var p=""<br />
while(a) {<br />
if(chop(a) == "1") {<br />
r=badd(r,b+p)<br />
}<br />
a=a.slice(0,-1)<br />
p+="0"<br />
}<br />
return r;<br />
}<br />
function bmod(a,m) { // binary modulo<br />
return bdiv(a,m).mod<br />
}<br />
function bdiv(a,m) { // binary divide & modulo<br />
// this.q = quotient this.mod=remainder<br />
var lm=m.length, al=a.length<br />
var p="",d<br />
this.q=""<br />
for(n=0; n<al; n++) {<br />
p=p+a.charAt(n);<br />
if(p.length<lm || (d=bsub(p,m)) == "") {<br />
this.q+="0"<br />
} else {<br />
if(this.q.charAt(0)=="0") {<br />
this.q="1"<br />
} else {<br />
this.q+="1"<br />
}<br />
p=d<br />
}<br />
}<br />
this.mod=bnorm(p)<br />
return this<br />
}<br />
function bmodexp(x,y,m) { // binary modular exponentiation<br />
var r="1"<br />
status("bmodexp "+x+" "+y+" "+m)<br />
while(y) {<br />
if(chop(y) == 1) {<br />
r=bmod(bmul(r,x),m)<br />
}<br />
y=y.slice(0,y.length-1)<br />
x=bmod(bmul(x,x),m)<br />
}<br />
return bnorm(r)<br />
}<br />
function modexp(x,y,m) { // modular exponentiation<br />
// convert packed bits (text) into strings of 0s and 1s<br />
return b2t(bmodexp(t2b(x),t2b(y),t2b(m)))<br />
}<br />
function i2b(i) { // convert integer to binary<br />
var r=""<br />
while(i) {<br />
if(i & 1) { r="1"+r} else {r="0"+r}<br />
i>>=1;<br />
}<br />
return r? r:"0"<br />
}<br />
function t2b(s) {<br />
var r=""<br />
if(s=="") {return "0"}<br />
while(s.length) {<br />
var i=s.charCodeAt(0)<br />
s=s.substr(1)<br />
for(n=0; n<8; n++) {<br />
r=((i & 1)? "1":"0") + r<br />
i>>=1;<br />
}<br />
}<br />
return bnorm(r)<br />
}<br />
function b2t(b) {<br />
var r=""; var v=0; var m=1<br />
while(b.length) {<br />
v|=chop(b)*m<br />
b=b.slice(0,-1)<br />
m<<=1<br />
if(m==256 || b=="") {<br />
r+=String.fromCharCode(v)<br />
v=0; m=1<br />
}<br />
}<br />
return r<br />
}<br />
b64s="abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_""<br />
function textToBase64(t) {<br />
status("t 2 b64")<br />
var r=""; var m=0; var a=0; var tl=t.length-1; var c<br />
for(n=0; n<=tl; n++) {<br />
c=t.charCodeAt(n)<br />
r+=b64s.charAt((c << m | a) & 63)<br />
a = c >> (6-m)<br />
m+=2<br />
if(m==6 || n==tl) {<br />
r+=b64s.charAt(a)<br />
if((n%45)==44) {r+="\n"}<br />
m=0<br />
a=0<br />
}<br />
}<br />
return r<br />
}<br />
function base64ToText(t) {<br />
status("b64 2 t")<br />
var r=""; var m=0; var a=0; var c<br />
for(n=0; n<t.length; n++) {<br />
c=b64s.indexOf(t.charAt(n))<br />
if(c >= 0) {<br />
if(m) {<br />
r+=String.fromCharCode((c << (8-m))&255 | a)<br />
}<br />
a = c >> m<br />
m+=2<br />
if(m==8) { m=0 }<br />
}<br />
}<br />
return r<br />
}<br />
function rand(n) { return Math.floor(Math.random() * n) }<br />
function rstring(s,l) {<br />
var r=""<br />
var sl=s.length<br />
while(l-->0) {<br />
r+=s.charAt(rand(sl))<br />
}<br />
//status("rstring "+r)<br />
return r<br />
}<br />
function key2(k) {<br />
var l=k.length<br />
var kl=l<br />
var r=""<br />
while(l--) {<br />
r+=k.charAt((l*3)%kl)<br />
}<br />
return r<br />
}<br />
function rsaEncrypt(keylen,key,mod,text) {<br />
// I read that rc4 with keys larger than 256 bytes doesn"t significantly<br />
// increase the level of rc4 encryption because it"s sbuffer is 256 bytes<br />
// makes sense to me, but what do i know...<br />
status("encrypt")<br />
if(text.length >= keylen) {<br />
var sessionkey=rc4(rstring(text,keylen),rstring(text,keylen))<br />
// session key must be less than mod, so mod it<br />
sessionkey=b2t(bmod(t2b(sessionkey),t2b(mod)))<br />
alert("sessionkey="+sessionkey)<br />
// return the rsa encoded key and the encrypted text<br />
// i"m double encrypting because it would seem to me to<br />
// lessen known-plaintext attacks, but what do i know<br />
return modexp(sessionkey,key,mod) +<br />
rc4(key2(sessionkey),rc4(sessionkey,text))<br />
} else {<br />
// don"t need a session key<br />
return modexp(text,key,mod)<br />
}<br />
}<br />
function rsaDecrypt(keylen,key,mod,text) {<br />
status("decrypt")<br />
if(text.length <= keylen) {<br />
return modexp(text,key,mod)<br />
} else {<br />
// sessionkey is first keylen bytes<br />
var sessionkey=text.substr(0,keylen)<br />
text=text.substr(keylen)<br />
// un-rsa the session key<br />
sessionkey=modexp(sessionkey,key,mod)<br />
alert("sessionkey="+sessionkey)<br />
// double decrypt the text<br />
return rc4(sessionkey,rc4(key2(sessionkey,text),text))<br />
}<br />
}<br />
function trim2(d) { return d.substr(0,d.lastIndexOf("1")+1) }<br />
function bgcd(u,v) { // return greatest common divisor<br />
// algorythm from http://algo.inria.fr/banderier/Seminar/Vallee/index.html<br />
var d, t<br />
while(1) {<br />
d=bsub(v,u)<br />
//alert(v+" - "+u+" = "+d)<br />
if(d=="0") {return u}<br />
if(d) {<br />
if(d.substr(-1)=="0") {<br />
v=d.substr(0,d.lastIndexOf("1")+1) // v=(v-u)/2^val2(v-u)<br />
} else v=d<br />
} else {<br />
t=v; v=u; u=t // swap u and v<br />
}<br />
}<br />
}<br />
function isPrime(p) {<br />
var n,p1,p12,t<br />
p1=bsub(p,"1")<br />
t=p1.length-p1.lastIndexOf("1")<br />
p12=trim2(p1)<br />
for(n=0; n<2; n+=mrtest(p,p1,p12,t)) {<br />
if(n<0) return 0<br />
}<br />
return 1<br />
}<br />
function mrtest(p,p1,p12,t) {<br />
// Miller-Rabin test from forum.swathmore.edu/dr.math/<br />
var n,a,u<br />
a="1"+rstring("01",Math.floor(p.length/2)) // random a<br />
//alert("mrtest "+p+", "+p1+", "+a+"-"+p12)<br />
u=bmodexp(a,p12,p)<br />
if(u=="1") {return 1}<br />
for(n=0;n<t;n++) {<br />
u=bmod(bmul(u,u),p)<br />
//dg+=u+" "<br />
if(u=="1") return -100<br />
if(u==p1) return 1<br />
}<br />
return -100<br />
}<br />
pfactors="11100011001110101111000110001101"<br />
// this number is 3*5*7*11*13*17*19*23*29*31*37<br />
function prime(bits) {<br />
// return a prime number of bits length<br />
var p="1"+rstring("001",bits-2)+"1"<br />
while( ! isPrime(p)) {<br />
p=badd(p,"10"); // add 2<br />
}<br />
alert("p is "+p)<br />
return p<br />
}<br />
function genkey(bits) {<br />
q=prime(bits)<br />
do {<br />
p=q<br />
q=prime(bits)<br />
} while(bgcd(p,q)!="1")<br />
p1q1=bmul(bsub(p,"1"),bsub(q,"1"))<br />
// now we need a d, e, and an n so that:<br />
// p1q1*n-1=de -> bmod(bsub(bmul(d,e),"1"),p1q1)="0"<br />
// or more specifically an n so that d & p1q1 are rel prime and factor e<br />
n="1"+rstring("001",Math.floor(bits/3)+2)<br />
alert("n is "+n)<br />
factorMe=badd(bmul(p1q1,n),"1")<br />
alert("factor is "+factorMe)<br />
//e=bgcd(factorMe,p1q1)<br />
//alert("bgcd="+e)<br />
e="1"<br />
// is this always 1?<br />
//r=bdiv(factorMe,e)<br />
//alert("r="+r.q+" "+r.mod)<br />
//if(r.mod != "0") {alert("Mod Error!")}<br />
//factorMe=r.q<br />
d=bgcd(factorMe,"11100011001110101111000110001101")<br />
alert("d="+d)<br />
if(d == "1" && e == "1") {alert("Factoring failed "+factorMe+" p="+p+" q="+q)}<br />
e=bmul(e,d)<br />
r=bdiv(factorMe,d)<br />
d=r.q<br />
if(r.mod != "0") {alert("Mod Error 2!")}<br />
this.mod=b2t(bmul(p,q))<br />
this.pub=b2t(e)<br />
this.priv=b2t(d)<br />
}<br />
function status(a) { }//alert(a)}<br />
// --><br />
</script><br />
<h3>RSA-type:</h3><br />
Note that long keys will likely be slow. <p><br />
<form method="POST" name="RSA"><br />
<div align="center"><br />
<table border="0"><br />
<tr><br />
<td align="right">keylength:</td><br />
<td><input type="text" size="4" name="keylen" value="2"> How many bytes?</td><br />
<td>&nbsp;</td><br />
</tr><br />
<tr><br />
<td align="right">key:</td><br />
<td><input type="text" size="60" name="key" value="10001"></td><br />
<td>Binary</td><br />
</tr><br />
<tr><br />
<td><br />
<p align="right">modulo:</p><br />
</td><br />
<td><input type="text" size="60" name="mod" value="110010100001"></td><br />
<td>Binary</td><br />
</tr><br />
<tr><br />
<td align="right">text:</td><br />
<td><textarea name="text" rows="6" cols="60"></textarea></td><br />
<td>For sample values you can use:<br><br />
Public Key: 10001<br><br />
Modulo: 110010100001<br><br />
Private Key: 101011000001</td><br />
</tr><br />
<tr><br />
<td align="right"><br />
<script language="JavaScript"><!--<br />
function RSAencryptDemo() {<br />
document.RSA.text.value=textToBase64(<br />
rsaEncrypt(<br />
parseInt(document.RSA.keylen.value),<br />
b2t(document.RSA.key.value),<br />
b2t(document.RSA.mod.value),<br />
document.RSA.text.value))<br />
document.RSA.key.value="101011000001"<br />
}<br />
function RSAdecryptDemo() {<br />
document.RSA.text.value=rsaDecrypt(<br />
parseInt(document.RSA.keylen.value),<br />
b2t(document.RSA.key.value),<br />
b2t(document.RSA.mod.value),<br />
base64ToText(document.RSA.text.value))<br />
document.RSA.key.value="10001"<br />
}<br />
// --></script><br />
</td><br />
<td><br />
<p align="center"><input type="button" name="B1" value="Encrypt" onclick="RSAencryptDemo()"><br />
<input type="button" name="B2" value="Decrypt" onclick="RSAdecryptDemo()"><br />
</p><br />
</td><br />
</tr><br />
</table><br />
</div><br />
</form><br />
</body><br />
</html><br />
<br />
</source></div>
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