Rsa encrypt

var RSAPublicKey = function($modulus_hex, $encryptionExponent_hex) {
    this.modulus = new BigInteger( $modulus_hex, 16);
    this.encryptionExponent = new BigInteger( $encryptionExponent_hex, 16);
};

var Base64 = {
    base64: "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",
    encode: function($input) {
        if (!$input) {
            return false;
        }
        var $output = "";
        var $chr1, $chr2, $chr3;
        var $enc1, $enc2, $enc3, $enc4;
        var $i = 0;
        do {
            $chr1 = $input.charCodeAt($i++);
            $chr2 = $input.charCodeAt($i++);
            $chr3 = $input.charCodeAt($i++);
            $enc1 = $chr1 >> 2;
            $enc2 = (($chr1 & 3) << 4) | ($chr2 >> 4);
            $enc3 = (($chr2 & 15) << 2) | ($chr3 >> 6);
            $enc4 = $chr3 & 63;
            if (isNaN($chr2)) $enc3 = $enc4 = 64;
            else if (isNaN($chr3)) $enc4 = 64;
            $output += this.base64.charAt($enc1) + this.base64.charAt($enc2) + this.base64.charAt($enc3) + this.base64.charAt($enc4);
        } while ($i < $input.length);
        return $output;
    },
    decode: function($input) {
        if(!$input) return false;
        $input = $input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
        var $output = "";
        var $enc1, $enc2, $enc3, $enc4;
        var $i = 0;
        do {
            $enc1 = this.base64.indexOf($input.charAt($i++));
            $enc2 = this.base64.indexOf($input.charAt($i++));
            $enc3 = this.base64.indexOf($input.charAt($i++));
            $enc4 = this.base64.indexOf($input.charAt($i++));
            $output += String.fromCharCode(($enc1 << 2) | ($enc2 >> 4));
            if ($enc3 != 64) $output += String.fromCharCode((($enc2 & 15) << 4) | ($enc3 >> 2));
            if ($enc4 != 64) $output += String.fromCharCode((($enc3 & 3) << 6) | $enc4);
        } while ($i < $input.length);
        return $output;
    }
};

var Hex = {
    hex: "0123456789abcdef",
    encode: function($input) {
        if(!$input) return false;
        var $output = "";
        var $k;
        var $i = 0;
        do {
            $k = $input.charCodeAt($i++);
            $output += this.hex.charAt(($k >> 4) &0xf) + this.hex.charAt($k & 0xf);
        } while ($i < $input.length);
        return $output;
    },
    decode: function($input) {
        if(!$input) return false;
        $input = $input.replace(/[^0-9abcdef]/g, "");
        var $output = "";
        var $i = 0;
        do {
            $output += String.fromCharCode(((this.hex.indexOf($input.charAt($i++)) << 4) & 0xf0) | (this.hex.indexOf($input.charAt($i++)) & 0xf));
        } while ($i < $input.length);
        return $output;
    }
};

var RSA = {

    getPublicKey: function( $modulus_hex, $exponent_hex ) {
        return new RSAPublicKey( $modulus_hex, $exponent_hex );
    },

    encrypt: function($data, $pubkey) {
        if (!$pubkey) return false;
        $data = this.pkcs1pad2($data,($pubkey.modulus.bitLength()+7)>>3);
        if(!$data) return false;
        $data = $data.modPowInt($pubkey.encryptionExponent, $pubkey.modulus);
        if(!$data) return false;
        $data = $data.toString(16);
        if(($data.length & 1) == 1)
            $data = "0" + $data;
        return Base64.encode(Hex.decode($data));
    },

    pkcs1pad2: function($data, $keysize) {
        if($keysize < $data.length + 11)
            return null;
        var $buffer = [];
        var $i = $data.length - 1;
        while($i >= 0 && $keysize > 0)
            $buffer[--$keysize] = $data.charCodeAt($i--);
        $buffer[--$keysize] = 0;
        while($keysize > 2)
            $buffer[--$keysize] = Math.floor(Math.random()*254) + 1;
        $buffer[--$keysize] = 2;
        $buffer[--$keysize] = 0;
        return new BigInteger($buffer);
    }
};