Ciphers

Caesar Cipher

In the time of the Caesars a code method was developed. It became known as the Caesar Cipher.

The Cipher used the idea of an Alphabet shift. Say, using the English alphabet we shift 1 this means that a is now b and b is now c, and so on.

Vigenère Cipher

A Vigenère Cipher uses the same idea as a Caesar Cipher but instead of a standard shift it uses a keyword shift.

For example; If I want to send the word "hello" as a Vigenère Cipher I might choose a Keyword like dog as my shift. D - is letter 3, O - is letter 14, G - is letter 6. This means that I will rotate the shifts by 3, 14, 6. So "hello" is shifted like this;

normal text	h	e	l	l	o
SHIFT (Keyword DOG)	D-3	O-14	G-6	D-3	O-14
Coded text	h+3=k	e+14=s	l+6=r	l+3=o	o+14=c

Thus the coded "hello" text becomes ksroc. As you can see this is a very powerful cipher. Even the two 'l's in the middle of hello don't look like doubles!

The longer your keyword is the more combinations there are to decode - this is quite a hard cipher to crack but computers can crack it.

One-Time Pad

The One-Time Pad is a more complicated version of the Vigenère Cipher. Essentially the length of the keyword matches the length of the message. Generally also the keyword is not a keyword at all but a random generated set of numbers used to shift each letter in a random way. As with all SHIFTS, KEYWORDS, or RANDOM KEYS they need to be communicated to the correct recipient of the message to be used to decode the message and this presents other problems.

Asymmetric Encryption

>Thanks Geeks for Geeks<

Asymmetric encryption, also known as public-key cryptography, is a type of encryption that uses a pair of keys to encrypt and decrypt data. The pair of keys includes a public key, which can be shared with anyone, and a private key, which is kept secret by the owner.

What is an Asymmetric Encryption?

In asymmetric encryption, the sender uses the recipient's public key to encrypt the data. The recipient then uses their private key to decrypt the data. This approach allows for secure communication between two parties without the need for both parties to have the same secret key. Asymmetric encryption has several advantages over symmetric encryption, which uses the same key for both encryption and decryption. One of the main advantages is that it eliminates the need to exchange secret keys, which can be a challenging process, especially when communicating with multiple parties.

Additionally, asymmetric encryption allows for the creation of digital signatures, which can be used to verify the authenticity of data. Asymmetric encryption is commonly used in various applications, including secure online communication, digital signatures, and secure data transfer. Examples of asymmetric encryption algorithms include RSA, Diffie-Hellman, and Elliptic Curve Cryptography (ECC).

Asymmetric encryption, commonly known as public-key cryptography, employs two distinct keys for encryption and decoding. The private key is a separate key from the public key that is kept private by the owner of the public key while the public key is made available to everyone. Anyone can encrypt a message using the public key, but only the holder of the private key can unlock it. With no chance of the communication being intercepted and read by a third party, anyone can send a secure message to the public key's owner.

Asymmetric encryption is frequently used for secure Internet communication, including email encryption, e-commerce, and online banking. Digital signatures, which are used to confirm the legitimacy of digital documents and messages, are another application for it.