SSL Protocol

Secure Socket Layer Protocol

The SSL protocol performs message exchanges as in figure. Assume that the sender is Sally, the receiver Is Richard.

Step 1: At Sally’s site the message to be sent is hashed to a previously fixed length for message digest.

Step 2: The message digest is encrypted with Sally’s private signature key using an RSA algorithm. And the output is a digital signature.

Step 3: The digital signature and Sally’s certificate are attached to the original message. In the meantime, a secret key using the DES algorithm at Sally’s computer encrypts the bundle with the key.

Step 4: The symmetric key is encrypted with Richards’s public key, which resides in the Richard’s certificate, received in advance. The result is digital envelope.
Step 5: The encrypted message and digital envelope are transmitted to Richard’s computer over the Internet.

Step 6: The digital envelope is decrypted with Richards’s private exchange key.

Step 7: Using the restored secret key, the delivered message is decrypted to the message, digital signature, and Sally’s certificate.

Step 8: To confirm the integrity, the digital signature is decrypted by Sally’s public key (that resides in Sally’s certificate). Obtaining the message digest.

Step 9: The delivered message is hashed to generate a message digest

Step 10: The message digest obtained by step 8 and 9 are compared whether there is any change during the transmission. This step confirms the integrity.