title: TLS- Are there two digital signature in play during handshake
body: <p>Could you please clarify on the below doubt. 
  From IBM website,
  <a href="https://www.ibm.com/support/knowledgecenter/en/SSFKSJ_7.1.0/com.ibm.mq.doc/sy10520_.htm" rel="nofollow noreferrer">https://www.ibm.com/support/knowledgecenter/en/SSFKSJ_7.1.0/com.ibm.mq.doc/sy10520_.htm</a></p>
  
  <p>The steps of the digital signature process are as follows:</p>
  
  <pre><code>The sender computes a message digest and then encrypts the digest using the sender's private key, forming the digital signature.
  The sender transmits the digital signature with the message.
  The receiver decrypts the digital signature using the sender's public key, regenerating the sender's message digest.
  The receiver computes a message digest from the message data received and verifies that the two digests are the same.
  </code></pre>
  
  <p>So there is a digital signature created using the some random message during handshake. Along with it, there is a digital signature value in the personal certificate issued by CA which is called "Digital Signature Value".  This Signature value is present in the certificate itself. But there is one more signature value created from random message during handshake also.  Why we have 2 times signature here  even for one way SSL. Where is my understanding wrong?. Thanks .</p>