Servage Magazine

Here is another blog in our SSH series. This blog focuses on giving an overview of the  cryptology algorithms which is used by SSH. The encryption methods used by SSH can be broadly classified into 3 types:

• Symmetrical encryption :
  Here a secret key is used for encryption and decryption. Both the client and host use the keys. To decrypt the message one must have the key, which is open to anyone.
  The advantage is that we can encrypt entire communication between server and your terminal during the SSH session. The client and server derive the secret key using an agreed method which is kept secret between them.

• Asymmetrical encryption :
  Asymmetrical encryption uses two separate keys pairs for encryption and decryption. These two keys are known as the public key and the private key. Together, both these keys form a public-private key pair.
  The public key is shared with all parties. The second private key is kept a secret so that you can only know. A message that is encrypted using a public key can only be decrypted using a private key, while also, a message encrypted using a private key can be decrypted using a public key. Security of the public key is not required because it is publicly available and can be passed over the internet. Asymmetric key has a far better power in ensuring the security of information transmitted during communication.

• Hashing :
  Another way is one-way hashing technique. A unique value of fixed length is generated for each input and transmitted over. This makes is impossible to decrypt or uncover.
  It is easy to generate a cryptographic hash from a given input, but impossible to generate the input from the hash.This means that if a client holds the correct input, they can generate the crypto-graphic hash and compare its value to verify whether they possess the correct input.Here’s how it works: A user enters a password and an ID in a browser and sends it (preferably over a secure link) to the authentication server. The server uses the ID to look up the associated message digest. The password submitted by the user is then hashed with the same algorithm, and if the resulting message digest matches the one stored on the server, it is authenticated.

Summary:
SSH was developed as a superior ways to communicate with server in comparison with telnet. Using above listed ways to encrypt data makes is secure and safe to transmit information and keep hackers and snoopers at bay.

If you want to learn more about SSH and the encryption methods, you can check e.g. THIS PAGE. If you should have questions how to use SSH with your Servage Hosting Account, please get in touch with our support. We are available 24/7 via ticket (support@servage.net) or live chat which you find on www.servage.net