title: Public key confusion in digital signature
body: <p>A simple question :</p>
  
  <p>1, public key - for message encryption <br>
  2, private key - for message decryption <br></p>
  
  <p>in digital signature<br>
  1, private key - encrypt hashed value<br>
  2, public key - decrypt hashed value<br></p>
  
  <p>In my understanding public key is strictly for message encryption, and private key is strictly for message decryption only
  <br><br>
  as described what happens in digital signature confuses me.<br>
  public key is able to decrypt message as well ? <br><br>
  is it the difference between private and public key not as clear cut as 1 is strictly for encryption and another for decryption ?</p>