int dtls1_send_hello_verify_request(SSL *s)
	{
	unsigned int msg_len;
	unsigned char *msg, *buf, *p;

	if (s->state == DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A)
		{
		buf = (unsigned char *)s->init_buf->data;

		msg = p = &(buf[DTLS1_HM_HEADER_LENGTH]);
		/* Always use DTLS 1.0 version: see RFC 6347 */
		*(p++) = DTLS1_VERSION >> 8;
		*(p++) = DTLS1_VERSION & 0xFF;

		if (s->ctx->app_gen_cookie_cb == NULL ||
		     s->ctx->app_gen_cookie_cb(s, s->d1->cookie,
			 &(s->d1->cookie_len)) == 0)
			{
			SSLerr(SSL_F_DTLS1_SEND_HELLO_VERIFY_REQUEST,ERR_R_INTERNAL_ERROR);
			return 0;
			}

		*(p++) = (unsigned char) s->d1->cookie_len;
		memcpy(p, s->d1->cookie, s->d1->cookie_len);
		p += s->d1->cookie_len;
		msg_len = p - msg;

		dtls1_set_message_header(s, buf,
			DTLS1_MT_HELLO_VERIFY_REQUEST, msg_len, 0, msg_len);

		s->state=DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B;
		/* number of bytes to write */
		s->init_num=p-buf;
		s->init_off=0;
		}

	/* s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B */
	return(dtls1_do_write(s,SSL3_RT_HANDSHAKE));
	}

This weakness pertains to the use of cryptographic functions that are weak, misconfigured, or outdated, which undermines the intended protection of encrypted data and communications.