Security: Symmetic vs Asymmetic encryption vs Steganography

Objective: To tell you how to send private or secret messages to someone in 3 approaches
Part I: Symmetric Encryption (Shared-Key)

Example of Symmetric encryption: 
AES, Blowfish, DES (internal mechanics, Triple DES) Serpent, Twofish

You may try anywhere: http://aes.online-domain-tools.com/

+++ This sample I sample it by AES-256-OFB algorithm  +++
Encryption 
Input is hex converted from UTF8 (highlight below line to see utf8 to hex)

48617070792056616c656e74696c652773206461792066726f6d20544841494c414e4421

Key is hex converted from  UTF8: 7368617265646b657938383838
Init Vector is: e17815bcf321084b58d467f0b375f09c (256bits)
CipherText(Encrypted plaintext) : 7bba9cef2088823d6094dc38079a2f5b8a8d7bd21796d7a58719ddb72af05acf4c075d07
*** CipherText is thing you send to destination ***


Decryption       

      If you can decrypt it, you will see hex stings. You may convert those hex to utf8 to see clear plain text. I mean human can read it.

Pros:Easy to send Cipher Text(Encrypted plaintext) with the same key
Cons: 1. Easy to be notice

      2. If hacker or intruder know shared-key. It means your private messages leaked or breached

      3. This approach can be attacked by Eve or Mallory role of Man-In-The-Middle approach

      4. Few years ago, US Military use AES-256(Reference from WiKi). 

      5. Currently, there is a higher secure encryption,it is AES-512(Reference from IEEE)

Part II: Asymmetric Encryption (Public-Key and Private-Key)
              please learn by yourself. It's a basic.

Part III: Steganography (Personally like)***

   

        Please learn basic by yourself.  
I love this approach by enhancing it with cryptography and post it anywhere on social media.
Members all around the world know. For those who don't know,
don't worry I sent nothing just sent backup evidence to my trusted members to protect myself in case of emergency.

             It's hard to notice that it's hidden secret message on it. 
People might think it's just picture, file, media and so on. I have used it for years. 

+++ Pros and Cons of 3 approaches +++
Thanks below link for conclusion

I accidentally found this link once I have done Part I.
It's well-explained source.

https://www.ssl2buy.com/wiki/symmetric-vs-asymmetric-encryption-what-are-differences 

SSL Information

      Information security has grown to be a colossal factor, especially with modern communication networks, leaving loopholes that could be leveraged to devastating effects. This article presents a discussion on two popular encryption schemes that can be used to tighten communication security in Symmetric and Asymmetric Encryption. In principle, the best way to commence this discussion is to start from the basics first. Thus, we look at the definitions of algorithms and key cryptographic concepts and then dive into the core part of the discussion where we present a comparison of the two techniques.

Algorithms

      An algorithm is basically a procedure or a formula for solving a data snooping problem. An encryption algorithm is a set of mathematical procedure for performing encryption on data. Through the use of such an algorithm, information is made in the cipher text and requires the use of a key to transforming the data into its original form. This brings us to the concept of cryptography that has long been used in information security in communication systems.

Cryptography

       Cryptography is a method of using advanced mathematical principles in storing and transmitting data in a particular form so that only those whom it is intended can read and process it. Encryption is a key concept in cryptography – It is a process whereby a message is encoded in a format that cannot be read or understood by an eavesdropper. The technique is old and was first used by Caesar to encrypt his messages using Caesar cipher. A plain text from a user can be encrypted to a ciphertext, then send through a communication channel and no eavesdropper can interfere with the plain text. When it reaches the receiver end, the ciphertext is decrypted to the original plain text.

Cryptography Terms

• Encryption: It is the process of locking up information using cryptography. Information that has been locked this way is encrypted.
• Decryption: The process of unlocking the encrypted information using cryptographic techniques.
• Key: A secret like a password used to encrypt and decrypt information. There are a few different types of keys used in cryptography.
• Steganography: It is actually the science of hiding information from people who would snoop on you. The difference between steganography and encryption is that the would-be snoopers may not be able to tell there’s any hidden information in the first place.

       This is the simplest kind of encryption that involves only one secret key to cipher and decipher information. Symmetrical encryption is an old and best-known technique. It uses a secret key that can either be a number, a word or a string of random letters. It is a blended with the plain text of a message to change the content in a particular way. The sender and the recipient should know the secret key that is used to encrypt and decrypt all the messages. Blowfish, AES, RC4, DES, RC5, and RC6 are examples of symmetric encryption. The most widely used symmetric algorithm is AES-128, AES-192, and AES-256.

       The main disadvantage of the symmetric key encryption is that all parties involved have to exchange the key used to encrypt the data before they can decrypt it.

      Asymmetrical encryption is also known as public key cryptography, which is a relatively new method, compared to symmetric encryption. Asymmetric encryption uses two keys to encrypt a plain text. Secret keys are exchanged over the Internet or a large network. It ensures that malicious persons do not misuse the keys. It is important to note that anyone with a secret key can decrypt the message and this is why asymmetrical encryption uses two related keys to boosting security. A public key is made freely available to anyone who might want to send you a message. The second private key is kept a secret so that you can only know.

      A message that is encrypted using a public key can only be decrypted using a private key, while also, a message encrypted using a private key can be decrypted using a public key. Security of the public key is not required because it is publicly available and can be passed over the internet. Asymmetric key has a far better power in ensuring the security of information transmitted during communication.

     Asymmetric encryption is mostly used in day-to-day communication channels, especially over the Internet. Popular asymmetric key encryption algorithm includes EIGamal, RSA, DSA, Elliptic curve techniques, PKCS.

Asymmetric Encryption in Digital Certificates

       To use asymmetric encryption, there must be a way of discovering public keys. One typical technique is using digital certificates in a client-server model of communication. A certificate is a package of information that identifies a user and a server. It contains information such as an organization’s name, the organization that issued the certificate, the users’ email address and country, and users public key.

      When a server and a client require a secure encrypted communication, they send a query over the network to the other party, which sends back a copy of the certificate. The other party’s public key can be extracted from the certificate. A certificate can also be used to uniquely identify the holder.

      SSL/TLS uses both asymmetric and symmetric encryption, quickly look at digitally signed SSL certificates issued by trusted certificate authorities (CAs).

Reference: https://en.wikipedia.org/wiki/Symmetric-key_algorithm

https://ieeexplore.ieee.org/document/6122835/


You may comment if you have another approach.
Thank you from THAILAND