question: public void init ( PrivateKey key ) { try { if ( signature != null ) { signature . initSign ( key ) ; } else if ( cipher != null ) { cipher . init ( Cipher . ENCRYPT_MODE , key ) ; } } catch ( InvalidKeyException e ) { throw new AlertException ( AlertProtocol . BAD_CERTIFICATE , new SSLException ( "init - invalid private key" , e ) ) ; } }
target:  Initiate Signature type by private key