The art and science of concealing and verifying information. In the
past, information was primarily concealed by linguistic methods
(riddles and the like), but with the rise of computers, mathematical
methods have become the norm for strong cryptography.
"Crypto" in this household means "Cryptography"
Terms to remember
Encryption Function
Transforming data into an unrecognizable or otherwise unusable form.
The process of reversing encryption is decryption.
Plaintext
This is data that is immediately recognizable and useful to
anyone with access to it.
Unencrypted data.
Ciphertext
Data that is obfuscated in some form to prevent immediate use by
those who have access to it.
Encrypted data.
Cryptographic Key
An arbitrary piece of data that is used to encrypt and decrypt data.
Trapdoor Function
a Mathematical
function
that is
trivial to perform in one direction, but is expensive (a lot of the
times, impossibly so) to reverse.
Also known as a one-way function.
Hashing Function
A Trapdoor Function that reduces a given input of arbitrary size
into a fixed-size array of numbers called a digest or hash.
This requires that the function be deterministic, meaning given the
exact same input, it must only ever return the same exact output.
Symmetric or Password Encryption
A method of encryption where the cryptographic key for BOTH
encryption and decryption is based on some piece of data normally a
called "password", or "passphrase" in cases where it is longer.
Assymetric or Public-Key Encryption
A method of encryption where the cryptographic key for encryption
(called a Public Key) is different from the key used for decryption,
(called a Private Key)
Identity / Keypair
A Keypair or Cryptographic Identity is a pair of keys used in
Public-Key Encryption. One key, normally called the Public Key, is
shared to others and is used to encrypt messages to the
recipient. The other key is called a Private Key, which is never
shared with anyone. This is used to decrypt information that was
previously encrypted with the Public Key.
In
cryptocurrencies
, the Public Key is used
as a person or entity's receiving address. The Private Key, is then
used to authorize sending funds from an existing balance. See
Wallet
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