What’s the difference between encoding, encryption and hashing?

Hashing is a one-way function that is applied to a variable-length piece of data (logically called "message") and produces a fixed-length of message digest. Along with a sender's private key, the message digest becomes a digital signature or fingerprint. By using the sender's public  key and the same hashing function, the recepient calculates the same hash value to ensure that the data sent by the sender is really him/her. Hashing is mainly used for authentication, nonrepudiation, and data integrity. Also, hashing mainly uses asymmetric key algorithms which are more secure but still can use symmetric keys.

 

Encryption is a two-way fucntion that is applied to a variable-length data and produces a fixed-length encrypted string. The recepient uses own private key to decrypt the message. The sender uses recepient's public key to encrypt the message. Like hashing, encryption can use both symmetric and asymmetric keys. However, it is not recommended to use asymmetric keys for encryption because it is slow and CPU-intensive.

 

Encoding (or encapsulation) is not a security component  like hashing or encryption and i see no reason of including it in the question. It is just a method for delivering or transferring packets from media to another media. Frame Relay or PPP encapsulation is an example.  

 

The first of three stages in the memory process, involving processes associated with receiving or registering stimuli through one or more of the senses and modifying that information.
Encryption means the scrambling of electronic information being stored and sent so that if someone wrongly receives such information it will not be readable.Hashing is the transformation of a string of characters into a usually shorter fixed-length value or key that represents the original string.

Encoding means to transform data from one format to another.
Encryption means data is not in usable/unreadable format for anyone unless he decrypts its.
Hashing is used to ensure the data integrity, so that it can be guaranteed that it's not altered.

Encoding is a process of transforming the format of the data into another format so that it easily transferable over a network, the purpose of encoding is only to maintain data usability and can be reversed(decoded) using the same algorithm that have been used for encoding, example of coding algorithms:ASCII, UNICODE, etc.
On the other hand encryption is also the process of transforming the plain text into cipher so that it can not be interfered by an unauthorized person, the goal is to maintain the confidentiality of the data and can be reversed(decrypted) using key(private key) depending upon the type of algorithm used that is symmetric or asymmetric, exampleof encrypting algorithms: AES, DES,3DES,RSA,etc.
Hashing on the other hand is always confused with encryption, it is different, its main goal is to maintain the integrity of data, so data is first hashed and then encrypted and the hash value is attached to the encrypted data and then it is transferred, when the recipient receives the data it decrypts it and hashes the data, if the hash attached to the data is matched, then it s sure that the data was from the sender(unmodified).
Remember u can not reverse the hashing algorithm, example of Hashing algorithms: SHA-1, MD5, etc