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Showing posts from November, 2019

Using SSH keys with no passphrase and Using SSH keys with a passphrase

Lab 3.1: Using SSH keys with no passphrase


So far you have been connecting to serverX primarily with ssh,
authenticating yourself with a password.
This lab will enhance and simplify yours
molify your ssh connections to server x by
using key based authentication instead of passwords.


si connections between the student accounts on station X and server x
are authenticated using ssh keys.

1.As student on stationx, generate an ssh publice

stationx generate an ssh public private key pair. Note that ssh h keygen should
mert command line switch, so that keys appropriate for the DSA algorithm
are generated.
Choose default options for key locations. Also, choose a null passphrase by pressing Enter
when prompted.

2. Use the ssh  copy  id command to add the key you just generated to studente serverx's list

of authorized keys. Be sure to specify the path to your key with the i option.

3. You should now be able to access

perly configured, ssh will fall back to password authenti…

Generating Digital Certificates

Generating Digital Certificates

: X. 509 Certificate Format
: Generate a public private key pair and       define identity

Two Options

Use a Certificate Authority

Generate signature request (csr)
Send csr to CA

Receive signature from CA
Self Signed Certificates

Sign your own public key

Currently, the Internet has standardized on a certificate format known as X. 509. The X. 509 format
associates a public key with an identity, and is generally only valid for a given time period. The identity can
be composed of arbitrary name value pairs, but is currently generally composed the following minimum set
Country, Province or State, Organization Name, Common Name, and Email.

The first step is to generate a public private key pair, which can be done with the openssl command
assuming a 1024bit key

openssi genrsa out servert. Key. pem 1024

Next, in order to generate a certificate signature request (csr) an identity must be established. The

following command will read in the generated key pair, prompt for identity …

public Key Infrastructures

public Key Infrastructures 

Asymmetrical  encryption depends on public key integrity 

Tuvo a pproaches discourage rogue public keys 

Publishing Key fingerprints

Public Key Infrastructure (PKI)

: Distributed web of trust
: Hierarchical certiricate Authorities

Digitel Certincates

The distribution of public keys is a fundamental weakness in asymmetric encryption schemes. In addition to
when Alice wants to send a message to Bob, she looks up Bob's key from a public key directory. However


signatures and on his business cards). When Alice obtains Bob's Key from a public key server she can
then compute her own fingerprint and compare it against the well known value.

Public Key Infrastructures

A more secure approach would be for Bob to have a third party that Alice trusts sign his public key. when
signed public key is referred to as a Certificate, and the trusted third party is referred to as a certificate

Digital Certificate

Owner : Public Key and Identity
Issuer : Detached signature and …

The Need For Enc The Need For Encryption ryption

The Need For Enc The Need For Encryption ryption

Susceptibility of unencrypted traffic
Password data sniffing
Data manipulation

Authentication manipulation
Equivalent to mailing on postcards
Insecure traditional protocols
telnet FTP POP3 etc. insecure passwords
sendmail NFS NIS etc. insecure information
rsh rcp etc. insecure authentication
While early networking protocols have provided an indispensable infrastructure,secure authentication and
privacy were often not part of their design As a result,today's networking implementations often provide
inadequate protection for the people who use them.
The mathematical field of number theory has provided cryptographic algorithms protocols and techniques
which provide various forms of networking security,including secure authentication,assurance of data
integrity,and privacy.

Cryptographic Building Blocks

- Random Number Generator
- One Way Hashes
- Symmetric Algorithms
- Asymmetric(Public Key)Algorithms
- Public Key Infrastructures
- Digital Certificates
- Imp…

Have you ever made sure that your call is not being recorded?

Have you ever made sure that your call is not being recorded?

 You get angry if someone records your call without your permission, but it often happens that you do not even know and your call is being recorded and if we want, in most other countries, including India, the call record will be free.  Doing is not considered legal

 How can you know if your call is being recorded by the government if the agencies have a call to record, then you can know if any ordinary people are recording your call but how do you know if your call was recorded by the government agency?  You may not know because government agencies are recording your call through telecom company but you use smart phone.  If you have to keep in mind some of the same things in terms of call recording

Listen carefully during the call

 The first rule is if you get a call or call someone, and after a few seconds or minutes, if the beep sounds, understand that your call is being recorded and yes during that call you can also ask tha…

Do you know how many benefits Ghee gives to our body? Learn the benefits of eating desi ghee daily

Do you know how many benefits Ghee gives to our body?
 Learn the benefits of eating desi ghee daily

 Many people believe that eating desi ghee increases fat and also increases some heart disease.
 But many people often eat to taste good, but this is an illusion of man

 Desi ghee is rich in vitamins not only for health but also for oral glow and hair.
 Ayurveda believes Desi ghee is alleviated.  There are many benefits to consuming it in the cold. Usually, if you eat one tablespoon of desi ghee every day, our body is very healthy.

 Mixing cow's ghee in a glass of milk will eliminate body fatigue and weakness.  Before bedtime, you should put a mild nasal drops in the nose to prevent nasal congestion.

:-  Deshi ghee is very beneficial for people who have joints pain.  Ghee massage on the joints starts to reduce the swelling.

 :-  Cow ghee plays great value in enhancing eyesight. Mix one teaspoon of cow half teaspoon in ghee on both the empty stomach or at bedtime at night.

:-  Desi ghee is a …

Applying a happy pill to women can prevent pregnancy ​

Applying a happy pill to women can prevent pregnancy

​ In the present case, if every woman wants one child then be it son or daughter, but it is often done that due to physical relationship, the fetus remains.

​ And to prevent this condition, women use contraceptive pills but sometimes the contraceptive pill does not work and the fetus remains

​ And often this medicine will cause side effects to the body of women, but now it will be used to prevent the fetus. This particular bandage is a common bandage discovered by scientists in Georgia.

​ And this bandage was first used in mice.  And in this experiment it was found to be completely safe after which it was also tested on women.
​ Scientists also saw the result of success.

​ Scientists have created a contraceptive patch that works like a contraceptive drug.  And the vaccine clings to the human body and slowly releases the contraceptive drug into women's blood for about 30 days.
​ This bindage is a very small device.  With a needle…