Importance of cryptography
Cryptography is important to secure data and communication over the internet.
Some important terms
The result of encrypting a plaintext
A method of encrypting or decrypting data. Modern cipher are cryptographic, but there are many non-cryptographic cipher like Caesar cipher.
Data before encryption, often text but not always. Could be a photograph or other file.
Transforming plaintext into ciphertext, using a cipher
Not a form of encryption, just a form of data representation. Example - Base64
Soem information that is needed to correctly decrypt the ciphertext and obtain the plaintext.
Seperate to the key, a passphrase is a password to protect the key
Attacking cryptography by finding a weakness in unerlying maths.
Usage of cryptography with examples
Cryptography is used to protect confidentiality, ensure integrity and ensure authenticity
When you connect to SSH, your client and server establish an encrypted tunnel so that no one can snoop on your sessio.
When you connect to your bank, there is a certificate that uses cryptography to prove that it actually your bank.
When you download a file, you can use cryptography here to verify a checksum of data