Symmetric keys and asymmetric key in Block chain

Symmetric Key

• A symmetric key algorithm require the same key for both encryption of a plaintext and decryption of a cipher text.
• This same key is also called a shared secret.
• Symmetric key algorithm are generally much faster (hundreds to thousands times) to encrypt and decrypt a message than asymmetric key algorithm.
•  Big disadvantage of using a symmetric key algorithm is that both sender (Alice) and receiver (Bob) needs to know the shared secret.
• Few symmetric key algorithms: AES (Advanced Encryption Standard). Triple DES (Data Encryption Standard)

Example :-

Asymmetric Key

• An asymmetric key algorithm requires two keys called a public key and private key. One of the key is used for encryption of a plaintext and the other key is used for decryption of the cipher text.
• If Alice generates a private key and a corresponding public key, than anyone allowed to know her public key, but Alice must keep her private secret.
• A big disadvantage is that asymmetric key algorithms are generally much slower (hundred to thousands times) to encrypt and decrypt a message than symmetric key algorithms.
• The advantage of using an asymmetric key algorithm is that any sender can encrypt a message using the receiver public key, but only the receiver can decrypt the cipher text using its private key.
• A public key and private key are mathematically interconnected. Meaning each public key has only one corresponding private key.
• Few asymmetric key algorithms: RSA (Rivest Shamir Adleman), ECDSA (Elliptic Curve Digital Signature Algorithm)
• In blockchain the Elliptic Curve Digital Signature Algorithm is often used.

Examples :-