tag = ber_skip_tag( ber, &len ); /* SignatureAlg */
ber_skip_data( ber, len );
tag = ber_peek_tag( ber, &len ); /* IssuerDN */
tag = ber_skip_tag( ber, &len ); /* SignatureAlg */
ber_skip_data( ber, len );
tag = ber_peek_tag( ber, &len ); /* IssuerDN */