OTP-Pi

OTP or One Time Password is a one-time use password that has a certain validity period. Generally the validity period is made very short and only gives the chance to the recipient to enter it into the application and send it to the application server that requires it. OTP is strictly confidential so the clear text of the OTP should not be stored by any party. In fact, the application server only stores the hash or token that matches the OTP. Clear text is only generated and then sent to the recipient. In other words, clear text is only known to the OTP recipient.

The most popular OTPs are sent via SMS or Short Message Service. The use of SMS has the following advantages:

Can only be received by the device where the SIM card is installed. This of course comply What you have rule in multifactor authentication
Easily readable on almost all makes and models of mobile phone devices
Generally the device immediately notifies the presence of an incoming message without requiring user action
On smartphone devices, applications can directly read the message if permitted by the user. Thus, the application can directly verify the OTP without requiring manual action from the user. This will save time and reduce errors
Does not require the recipient's credit so that the recipient of the message does not have to pay anything to be able to receive the message
Has a very wide range
SMS receiving devices are available in various price classes so that they can be reached by almost all people

Of the many advantages above, it turns out that SMS has limitations. SMS must be sent through a telecommunications operator legally registered in the sending country. SMS can be sent using a GSM device connected to a telecommunications operator. The cheapest devices for sending SMS are cell phones and modems. In addition, the sender must pay a service fee to the telecommunications operator. This fee will be shared to all operators involved in sending SMS.

Another way to send SMS is by working directly with telecommunications operators or using third party services. Cooperation with telecommunications operators is certainly not easy. In addition to having a legal entity, the costs required are of course not small. In addition, the volume of SMS sending is also a consideration for whether the cooperation is accepted or not by the telecommunications operator. The use of third party services is another option. The safety factor is of course a consideration. The service provider must of course be trusted to maintain the confidentiality of the OTP sent.

For small-scale companies who want to build their own OTP delivery system, they can use a variety of applications that are available for free or paid in the market. Some considerations in choosing an OTP application are as follows:

Delivery speed
Security/confidentiality
Ease of installation and integration
Initial costs and operational costs

Applications that use a database to connect between the receiving side of the message and the GSM modem are of course not secure. The data in the database can be read by the administrator. In fact, administrators can request OTP when the user is not aware of it and is not transacting.

Applications that require the use of a public IP address of course do not provide flexibility for users. Companies or individuals who do not subscribe to the internet with a public IP cannot use the application. Users need to place the server on a network with a public IP.

Applications that run on desktops and laptops of course require high investment and operational costs. The laptop or desktop that is used must operate 24 hours a day and 7 days a week. Of course, the electricity used is not small.

OTP-Pi answers all of the above challenges. With a very cheap device, users can have an SMS gateway that provides many features and can be operated at a very low cost.

OTP-Pi is a server for sending SMS via HTTP, WebSocket and Message Broker protocols. Users can install OTP-Pi on the server with a static IP address that can be accessed by clients who will send SMS. In addition, users can also install OTP-Pi on servers with dynamic IP addresses. This server then accesses a websocket server, RabbitMQ server or Mosquitto server. OTP-Pi acts as a consumer that will send all SMS it receives.

To publish message using PHP to RabbitMQ, Mosquitto and Redis, see example on https://github.com/kamshory/OTP-Publisher

No RDBMS Required

OTP-Pi does not require an RDBMS. All data is stored in RAM and file system. The OTP-Pi also does not store the sent OTP. This will increase the security and confidentiality of the OTP.

System Requirement

Raspberry Pi 3 Model B or higher.
Minimum RAM is 1 GB.
SD Card minimum is 16 GB. 32 GB SD Card is recommended.
Power supply 5 Volt 3 Ampre to prevent the Raspberry Pi from operating with under voltage.
RTC DS3231 installed on Raspberry Pi.
Java Runtime Environment (JRE) 1.8 or Java Development Kit (JDK) 1.8.

Features

Built-in Wifi

OTP-Pi comes with built-in wifi. The built-in wifi is used to configure the device so that the OTP-Pi can be installed on your wired network. The built-in wifi is also useful when you are going to reset the OTP-Pi configuration.

Multiple Method

User can send OTP with several methods. OTP-Pi allow user to create and validate OTP via REST API or just send SMS or email contains OTP code via RabbitMQ, Redis, Mosquitto, ActiveMQ and WebSocket.

Method	Send SMS	Send Email	Block MSISDN	Unblock MSISDN	Create OTP	Validate OTP
REST API	✓	✓	✓	✓	✓	✓
WebSocket	✓	✓	✓	✓	✓	Require callback
RabbitMQ*	✓	✓	✓	✓	✓	Require callback
Redis*	✓	✓	✓	✓	✓	Require callback
Mosquitto*	✓	✓	✓	✓	✓	Require callback
ActiveMQ*	✓	✓	✓	✓	✓	Require callback
Stomp*	✓	✓	✓	✓	✓	Require callback

If you wish all features to be enable from API, you can use OTP-Publisher. Clone https://github.com/kamshory/OTP-Publisher to get it.

Vendors

Multiple Device

Modem is a list of modems installed on the OTP-Pi. Modems are named based on the make and model of the device and the connection used. The modem can be turned on and off at any time. An inactive modem will not be used to send SMS even if it is physically attached to the OTP-Pi and receiving power.

OTP-Pi can use multiple modems at once. By default, the OTP-Pi can use up to 4 modems at once without the need for additional devices. The use of a hub is possible so that users can use more than 4 modems in one OTP-Pi device. The modems are registered as usual. Sending SMS will use the Round-Robin algorithm where all active modems will be used in rotation.

Device Inspector

OTP-Pi will periodically check all serial ports on the server. If a device change is detected, the OTP-Pi will check the list of pre-set modems. If the port is used on one of the modems on the list, the OTP-Pi will update the modem connection status. In addition, OTP-Pi will also display a notification on the administrator screen.

Prefix-Based Routing

In reality, cost efficiency becomes very important for users. The cost of sending SMS should be reduced as much as possible. Telecommunications operators usually apply lower cost when sending SMS to subscriber numbers of the same telecommunications operator. On the other hand, the cost of sending SMS will be higher when sending SMS to customer numbers from other operators.

OTP-Pi allows users to set up SMS sending. For example: a user uses 4 modems with 4 different SIM cards from different telecommunication operators.

Modem 1 with SIM Card from Telecommunications Operator 1
Modem 2 with SIM Card from Telecommunications Operator 2
Modem 3 with SIM Card from Telecommunications Operator 3
Modem 4 with SIM Card from Telecommunications Operator 4

Telecommunications Operator 1 applies a fee of IDR 50 for numbers with prefixes 62871 and 62872 and applies a fee of IDR 350 for numbers other than that. Telecommunications Operator 2 applies a fee of IDR 100 for numbers with prefixes 62835, 62856, and 62837 and applies a fee of IDR 350 for numbers other than that. Telecommunications Operator 3 applies a fee of IDR 60 for numbers with the prefix 62845 and applies a fee of IDR 250 for numbers other than that. Telecommunications Operator 4 applies a fee of IDR 90 for numbers with prefixes 62848 and 62849 and applies a fee of IDR 200 for numbers other than that.

From the case above, the lowest cost for other operators is IDR 200. Users can set modem 4 as the default modem. All SMS other than the prefixes 62871, 62872, 62835, 62856, 62837 and 62845 will use this modem and are sent via Telecommunications Operator 4. All SMS for numbers with prefixes 62871 and 62872 uses modem 1 and is sent via Telecommunication Operator 1. All SMS for numbers with prefix 62835, 62856, and 62837 use modem 2 and are sent via Telecommunication Operator 2. All SMS for numbers with prefix 62845 use modem 3 and sent via Telecommunication Operator 3. Thus, the cost of sending SMS will be reduced.

Users can use 2 or more SIM cards from the same operator. The modem will be used interchangeably with the Round-Robin algorithm when OTP-Pi sends SMS to numbers with the same prefix.

The cost of sending SMS will be even lower when the user takes advantage of the promo from the telecommunications operator in question. Some operators will apply very low SMS sending fees after the user sends several SMS with certain conditions.

Prefix setting using MSISDN. Thus, in the example above, when a user in Indonesia sets the prefix 0871, it stores 62871. Thus, the user must use the prefix length of 5 instead of 4.

USSD Support

OTP-Pi allows users to perform USSD commands on individual modems. The USSD command, of course, depends on each telecomunications operator used on each SIM card installed on each modem.

Manual SMS

Manual SMS is used to test whether each modem can send SMS.

Internet Mobile

The OTP-Pi can connect to the internet using a mobile modem. Thus, users do not need to connect the OTP-Pi with wired or optical internet. It provides an alternative for users in choosing an internet connection.

Administrator Settings

Administrator Settings is a menu to configure administrator. New OTP-Pi devices don't have an administrator yet. The user must create an administrator first before using it. Please enter the OTP-Pi access point according to the SSID and password listed on the brochure and scan the QR Code on the brochure using a smartphone.

The default address of administration web is http://192.168.0.11:8888

Field	Description
Username	Administrator identifier when logging in to OTP-Pi
Password	Administrator's security when logging into OTP-Pi
Phone Number	The phone number can be used if the administrator forgets the password. Password will be sent via SMS. Of course this can only be done when the OTP-Pi has been configured correctly

E-mail

Email can be used if the administrator forgets the password. Password will be sent via email. Of course this can only be done when the OTP-Pi has been configured correctly.

API Settings

API Setting is a REST API configuration for sending SMS.

Field	Description
HTTP Port	The server port for HTTP
Enable HTTP	Setting to enable or disable HTTP port
HTTPS Port	he server port for HTTPS
Enable HTTPS	Setting to enable or disable HTTPS port
Message Path	The path to send SMS and email
Blocking Path	Path to block a phone number so that OTP-Pi does not send SMS to that number
Unblocking Path	Path to unblock a phone number so that OTP-Pi can send SMS to that number again

General Settings

Field	Description
Device Name	The device name of OTP-Pi
OTP Expiration	OTP expiration in mili second. It will be used when sender not send `expiration` on the OTP. OTP-Pi will not forward expire OTP.*
Drop Expire OTP	Flag that OTP-Pi will drop or ignone the expire OTP.*
Device Time Zone	The device time zone. Select one of the time zone listed
NTP Server	NTP server address to update the device time
Update Timer	Time to update the device time. Set to `Never` if the device is offline
Inspect Modem Connection	Time to update the modem connection. Set to `Never` if will not inspect the modem connection
Restart Service	Time to restart the service. Set to `Never` if you will not restart the device periodically
Restart Device	Time to reboot the device. Set to `Never` if you will not reboot the device periodically

*) Under abnormal conditions, the OTP may be delayed on the message broker and received by the OTP-Pi after expiration. OTP-Pi can ignore expired OTPs to avoid junk delivery. If the sender does not include expiration in the OTP, the expiration time will be calculated from date_time plus milliseconds in OTP Expiration. If the sender includes expiration in the OTP, the OTP-Pi will use that time.

Time Settings

Field	Description
Device Time	Device time
Device Time Zone	The device time zone. Select one of the time zone listed
NTP Server	NTP server address to update the device time
Update Timer	Time to update the device time. Set to `Never` if you will not restart the device periodically

API Users

API User is an account that sends SMS via REST API.

Field	Description
Username	Username is the sender identifier when sending SMS to OTP-Pi
Email	Email is contact information in the form of email addresses of API users
Phone Number	Phone number is contact information in the form of phone numbers from API users
Password	Username is the sender's security when sending SMS to OTP-Pi

Subscriber Settings

OTP-Pi provides an option if this device is installed on a mobile internet network or on a network where the sending device may not be able to reach the address of the OTP-Pi. Users can send OTP with message broker as follows:

RabbitMQ (AMQP)
Mosquitto (MQTT)
Redis
ActiveMQ
Stomp
WSMessageBroker (WebSocket)

WSMessageBroker

Field	Description
Enable	Enable or disable WSMessageBroker subscribsion
SSL	SSL connection
Host	WSMessageBroker host name or IP address
Port	Port number
Path	Context path
Username	Username on basic authorzation
Password	Password on basic authorzation
Topic	Topic or channel of subscribsion
Timeout	Request time out
Reconnect Delay	Delay to reconnect
Refresh Connection	Refresh WebSocket connection

RabbitMQ

Field	Description
Enable	Enable or disable RabbitMQ subscribsion
SSL	SSL connection
Host	RabbitMQ host name or IP address
Port	Port number
Version	AMQP version
Username	RabbitMQ username
Password	RabbitMQ password
Topic	Topic or channel of subscribsion
Timeout	Request time out
Reconnect Delay	Delay to reconnect
Refresh Connection	Refresh RabbitMQ connection

Mosquitto

Field	Description
Enable	Enable or disable Mosquitto subscribsion
SSL	SSL connection
Host	Mosquitto host name or IP address
Port	Mosquitto port number
Client ID	Client ID
Username	Username
Password	Password
Topic	Topic or channel of subscribsion
QoS	QoS of the subscribsion
Timeout	Request time out
Reconnect Delay	Delay to reconnect
Refresh Connection	Refresh Mosquitto connection

Redis

Field	Description
Enable	Enable or disable Redis subscribsion
SSL	SSL connection
Host	Redis host name or IP address
Port	Redis port number
Username	Client ID
Password	Redis password (if present)
Topic	Topic or channel of subscribsion
Timeout	Request time out
Reconnect Delay	Delay to reconnect
Refresh Connection	Refresh Redis connection

Stomp

Field	Description
Enable	Enable or disable Stomp subscribsion
SSL	SSL connection
Host	Stomp host name or IP address
Port	Stomp port number
Username	Username
Password	Password
Topic	Topic or channel of subscribsion
Timeout	Request time out
Reconnect Delay	Delay to reconnect
Refresh Connection	Refresh Stomp connection

ActiveMQ

Field	Description
Enable	Enable or disable ActiveMQ subscribsion
SSL	SSL connection
Host	ActiveMQ host name or IP address
Port	ActiveMQ port number
Client ID	Client ID
Username	Username
Password	Password
Topic	Topic or channel of subscribsion
Timeout	Request time out
Refresh Connection	Refresh ActiveMQ connection

SMS Settings

SMS Setting is the configuration of sending SMS by OTP-Pi.

Field	Description
Country Code	Phone country code (numeric). See https://countrycode.org/
Recipient Prefix Length	For Indonesia, use 5
Log Outgoing SMS	Flag to log outgoing SMS
Monitor SMS Traffic	Flag to monitor SMS traffic

Modem Settings

Field	Description
Name	Modem Name
Port	Serial port used
Manufacturer	Manufacturer identification
Model	Device model
Revision	Device revision
IMEI	Modem IMEI
IMSI	IMSI of the SIM Card used
Operator	Telecommunication operator
MSISDN	MSISDN of the SIM Card used
SMS Center	SMS center
Recipient Prefix	Recipient prefix that will receive SMS from this modem. See Prefix-Based Routing secton
SIM Card PIN	SIM Card PIN if exists
Baud Rate	Modem baud rate
Parity Bit	Modem parity bit
Start Bits	Modem start bits
Stop Bits	Modem stop bits
Internet Access	Use modem to connect to the internet
APN	Access Point Name
APN Username	Username of the APN to connect to the internet
APN Password	Password of the APN to connect to the internet
Dial Number	Number to be dialed to connect to the internet
Init Dial 1	Initial AT command to be executed to connect to the internet
Init Dial 2	Initial AT command to be executed to connect to the internet
Init Dial 3	Initial AT command to be executed to connect to the internet
Init Dial 4	Initial AT command to be executed to connect to the internet
Init Dial 5	Initial AT command to be executed to connect to the internet
Dial Command	Command to be executed to connect to the internet
Send SMS from API	Flag that the modem will be used to send SMS from API or not. If it set to `false`, modem will not send incomming SMS from API but user can send SMS manualy from the management web.
Default Modem	Flag that the modem is default or not. The default modem will be used to send SMS that the prefix is not exists on `Recipient Prefix` of the other modems.
Active	Flag for the modem that will be used or not

APN Settings for Indonesian Telco

Operator	APN	Username	Password	Dial UP
Telkmonsel	internet			*99#
XL	internet			*99#
Three	3data	3data	3data	*99#
Smartfren	smart	smart	smart	#777
Indosat Ooredoo	indosatgprs			*99#
Axis	axis	axis	123456	*99#

Blocking List

Blocking list is a list of blocked phone numbers. Blocked numbers will not receive SMS from any modem. This list can be added and whitened via the REST API, abbitMQ, Mosquitto and WebSocket. This list can also be manually added, whitened, or deleted via the web admin.

Multiple Email Account

OTP-Pi supports multiple email accounts. Email account is a configuration that contains SMTP Server address, SMTP server port, username, password, and other configurations.

SMTP Server is used to send OTP to email addresses and can be used to reset passwords.

The use of multiple email accounts is recommended because the number of emails sent by each email account will decrease. For example: an SMTP server limits 500 emails per day. Using 20 email accounts, OTP-Pi can send up to 10,000 emails per day.

To use Gmail SMTP, use the following configuration:

Use Port 587

Field	Value
SMTP Host	smtp.gmail.com
SMTP Port	587
SSL Enable	No
Start TLS Before Send	Yes
Authentication	Yes
Sender Account	Gmail Account
Sender Password	Gmail Password
Active	Yes

Use Port 465

Field	Value
SMTP Host	smtp.gmail.com
SMTP Port	465
SSL Enable	Yes
Start TLS Before Send	Yes
Authentication	Yes
Sender Account	Gmail Account
Sender Password	Gmail Password
Active	Yes

See https://mkyong.com/java/javamail-api-sending-email-via-gmail-smtp-example/

Bell Setting

The OTP-Pi is equipped with a passive buzzer. The passive buzzer will make a sound when an undesirable condition occurs. The user can set any conditions that will cause the buzzer to make a sound.

Field	Description
Fail Send SMS	Bell on SMS failure
AMQP Disconnected	Bell on RabbitMQ disconnected
MQTT Disconnected	Bell on Mosquitto disconnected
WS Disconnected	Bell on WebSocket disconnected

DDNS Record

DDNS Records are records for dynamic DNS settings. DDNS or Dymanic Domain Name System is a DNS setting mechanism that is done repeatedly because the public IP address of the server is always changing.

Field	Description
Provider	DNS server provider or vendor
Type	Record type. Currently only support `A Record`
Zone	Zone or domain name
Record Name	Record name or subdomain
TTL	Time to leave
Proxied	For Cloudflare only. It will use Cloudflare proxy and cache or not
Update DNS	Interval to update DNS. OTP-Pi will update it by sending request to the DNS server provider
Force Create Zone	For Cloudflare only. It will create zone if not exists
Active	Flag that DDNS record is active or not

OTP-Pi provides DDNS setup using DDNS vendor. Some of the supported DDNS vendors are as follows:

Cloudflare - https://www.cloudflare.com/
NoIP - https://www.noip.com/
Dynu Dyn DNS - https://www.dynu.com/
Free DNS Afraid - https://freedns.afraid.org/

Cloudflare Account

Field	Description
Cloudflare Endpoint	Cloudflare endpoint
Account ID	Cloudflare account ID
Email	Cloudflare email
API Key	Cloudflare API key
Token	Cloudflare Token
Active	Flag that this Cloudflare account is active or not

No IP Account

Field	Description
No IP Endpoint	No IP endpoint
Username	No IP username
Password	No IP password
Company Name	Your nompany name
Maintainer Email	Maintainer email or your company
Active	Flag that this No IP account is active or not

Dynu Account

Field	Description
API Version	Dynu API version
Dynu Endpoint	Dynu endpoint
API Key	Dynu API key
Username	Dynu username
Password	Dynu password
Company Name	Your nompany name
Maintainer Email	Maintainer email or your company
Active	Flag that this Dynu account is active or not

Afraid Account

Field	Description
Afraid Endpoint	Free DNS Afraid endpoint
Username	Free DNS Afraid username
Password	Free DNS Afraid password
Company Name	Your nompany name
Maintainer Email	Maintainer email or your company
Active	Flag that this Free DNS Afraid account is active or not

Network Setting

Network Setting is a configuration to manage network from OTP-Pi. OTP-Pi is equipped with an access point so that it can be accessed directly using a laptop or cellphone without having to plug it into a wired network. This will make it easier for users because the user's LAN network configuration is different. Users simply set the IP address on the ethernet network according to the LAN network configuration used.

DHCP

The DHCP configuration will set up DHCP on the OTP-Pi access point.

Field	Value
Domain Name	Domain name of DHCP
Domain Name Servers	Domain name servers of DHCP
Router Address	Router address of DHCP
Netmask	Netmask of DHCP
Subnetmask	Subnetmask of DHCP
Domain Name Servers Address	Domain Name Servers Address of DHCP
Default Lease Time	Default lease time of the clients
Maximum Lease Time	Maximum lease time of the clients
Range	Allocated IP address range

Example

Field	Value
Domain Name	otppi.lan
Domain Name Servers	ns1.otppi.lan, ns2.otppi.lan
Router Address	192.168.0.1
Netmask	255.255.255.0
Subnetmask	255.255.255.0
Domain Name Servers Address	192.168.0.11
Default Lease Time	3600
Maximum Lease Time	7200
Range	192.168.0.10-192.168.0.100, 192.168.0.110-192.168.0.200

The configuration above will create file /etc/dhcp/dhcpd.conf with its content as follows:

option domain-name "otppi.lan";
option domain-name-servers ns1.otppi.lan, ns2.otppi.lan;
default-lease-time 3600; 
max-lease-time 7200;
authoritative;

subnet 192.168.1.0 netmask 255.255.255.0 {
        option routers                  192.168.0.1;
        option subnet-mask              255.255.255.0;
        option domain-search            "otppi.lan";
        option domain-name-servers      192.168.0.11;
        range   192.168.0.10   192.168.0.100;
        range   192.168.0.110   192.168.0.200;
}

Wireless LAN

Wireless LAN configuration will set the IP address on the OTP-Pi wireless network. The default IP address of the OTP-Pi is 192.168.0.11

Field	Value
SSID Name	SSID name
SSID Password	SSID password
Key Management	Key management
IP Address	IP address of the device if client connect via Wifi
Prefix	Nework prefix
Netmask	Netmask
Gateway	Gateway
DNS	DNS

Ethernet

The Ethernet configuration will set the ethernet IP address on the OTP-Pi.

Field	Value
IP Address	IP address of the device if client connect via Ethernet
Prefix	Nework prefix
Netmask	Netmask
Gateway	Gateway
DNS1	DNS 1
DNS2	DNS 2

Firewalls

OTP-Pi can open and close ports of the operating system used by SMS Broker. Closing this port will create a firewall at the operating system layer. In this case, if the port is closed, the equest will not reach the application.

Monitor

The monitor can be used to view the activity of the modem installed on the OTP-Pi. When the OTP-Pi sends an SMS, the OTP-Pi will show where the SMS request came from and which modem was used. In addition, the status of the modem will be shown so that it will be seen which modems are connected correctly.

SMS Inbox

OTP-Pi provides a feature to read incoming SMS. The OTP-Pi will read all the SMS on the SIM card and move them to the storage on the device.

Users can delete the SMS when it is no longer needed. Users can also reply to the SMS manually from the OTP-Pi.

IMEI Tool

OTP-Pi provides a tool to change the IMEI of the modem. This tool is very useful for users who want to change IMEI for some reason. Users can directly enter the new IMEI and save it. The new IMEI will be written on the modem chip. Restarting the device may be required to implement the new IMEI on the GSM network.

SIM Tool

OTP-Pi provides tools to create or delete sim card PIN. This tool is very useful when the user chooses to use or not to use the PIN on the sim card.

Real Time Clock

The Real Time Clock or RTC module is required to keep the device time when the device is turned off and not connected to the internet. The device must use the correct time so that the cookies sent by the device are not deleted by the browser due to expiration so that the administrator can manage the device including making settings. In addition, the device needs to record the time when an error occurred so that the error log can be read by the user for mitigation.

The Real Time Clock module is built into the device and is programmed to work as intended. If the device is off for a long time causing the RTC battery to run out, the device can adjust the time according to the browser that accesses it regardless of the time zone used. Furthermore, the administrator can set the device time if needed.

Reset Device

In case the user cannot access the administration web, either because he forgot his password, or because the network configuration is messed up, the user can reset the device. Reset the device is done by plugging in a flash disk containing the following file:

/otppi/reset-config.ini

Directory name, file name and extension must be written correctly in lower case. The /otppi/reset-config.ini file should contain the following text:

VERIFY = eyJkZXZpY2VUeXBlIjoiUlBpIiwgImJhc2VOYW1lIjoicmVzZXQtY29uZmlnLmluaSJ9
RESET_DHCP = true
RESET_WLAN = true
RESET_ETHERNET = true
RESET_USER = true

RESET_API = false
RESET_API_USER = false
RESET_BLOCKING = false
RESET_DDNS = false
RESET_EMAIL = false
RESET_SUBSCRIBER_AMQP = false
RESET_SUBSCRIBER_MQTT = false
RESET_SUBSCRIBER_REDIS = false
RESET_SUBSCRIBER_ACTIVEMQ = false
RESET_SUBSCRIBER_STOMP = false
RESET_SUBSCRIBER_WS = false
RESET_FIREWALL = false
RESET_KEYSTORE = false
RESET_MODEM = false
RESET_SMS = false
RESET_SMTP = false

RESET_VENDOR_AFRAID = false
RESET_VENDOR_CLOUDFLARE = false
RESET_VENDOR_DYNU = false
RESET_VENDOR_NOIP = false

VERIFY must be set with eyJkZXZpY2VUeXBlIjoiUlBpIiwgImJhc2VOYW1lIjoicmVzZXQtY29uZmlnLmluaSJ9. Other configuration properties must be set with true or false. true means that you will reset the configuration and false means that you will not reset the configuration.

Reset device will do the following things:

A. Basic Configuration

RESET_DHCP (Restore the DHCP configuration to the default)
RESET_WLAN (Restore the Wireless LAN configuration to the default)
RESET_ETHERNET (Restore the LAN configuration to the default)
RESET_USER (Delete all administrator accounts)

B. Advanced Configuration

RESET_API
RESET_API_USER
RESET_BLOCKING
RESET_DDNS
RESET_EMAIL
RESET_SUBSCRIBER_AMQP
RESET_SUBSCRIBER_MQTT
RESET_SUBSCRIBER_REDIS
RESET_SUBSCRIBER_ACTIVEMQ
RESET_SUBSCRIBER_STOMP
RESET_SUBSCRIBER_WS
RESET_FIREWALL
RESET_KEYSTORE
RESET_MODEM
RESET_SMS
RESET_SMTP

C. Vendor Configuration

RESET_VENDOR_AFRAID
RESET_VENDOR_CLOUDFLARE
RESET_VENDOR_DYNU
RESET_VENDOR_NOIP

To reset the device, perform the following steps:

Prepare a flash disk with files as described above
Unplug all modems installed on the device
Insert the flash disk in any USB port of the device
Unplug the power supply to the device
Reconnect the power supply to the device
Wait up to 10 minutes
Remove the flash disk from the device
Reconnect the power supply to the device
Enter the access point with the SSID and password as stated in the brochure using a smartphone or PC
Open page 192.168.0.8888 with a browser using a smartphone or PC that has been connected to the access point above
Login to the page provided
Create a new administrator for the device

Topology

Both WebSocket and Message Broker use a topic that can be configured from both sides (sender and receiver).

To use WebSocket, please use the WSMessageBrocker library with the link https://github.com/kamshory/OTP-Publisher or you can create your own.

To use RabbitMQ, please open the link https://www.rabbitmq.com/

To use Redis, please open the link https://redis.io/

To use Mosquitto, please open the link https://mosquitto.org/

Scenario 1 - App Server Can Access OTP-Pi

In this scenario, the App Server can directly send the OTP to the OTP-Pi via HTTP.

Users can use a cheap domain and use the Dynamic Domain Name System for free. With the use of port forwarding on the router, OTP-Pi can be accessed from anywhere using a domain or subdomain. In this scenario, the user needs:

OTP-Pi
Fixed internet connection with public IP (static or dynamic)
Router that can do port forwarding
Domains whose name servers can be set
Dynamic DNS service (free or paid)

In this scenario, the application server can generate and validate the OTP sent for each transaction. OTP creation and validation requires the following parameters:

reference

reference is unique transaction reference number. This number must be different from one transaction to another. This number is the key to validate the OTP.

receiver

receiver is the phone number or email address of the recipient.

param1, param2, param3, param4

These four parameters are additional information for validating the OTP. These four parameters must be the same between OTP creation and validation. Of course this parameter can be filled with empty strings. Information that can be used as this parameter is for example the sender's account number, the recipient's account number, the transaction amount (in string format), and so on.

OTP-Pi does not store the clear OTP but only stores the hash. In addition, the OTP-Pi immediately deletes the SMS sent immediately after. Thus, the OTP is very safe because it is only known by the recipient.

1. Message Format

Create OTP Request

POST /api/otp HTTP/1.1
Host: sub.domain.tld
Connection: close
User-agent: KSPS
Content-type: application/json
Content-length: 313
Authorization: Basic dXNlcjpwYXNzd29yZA==

{
    "command": "request-otp",
    "data": {
        "date_time": 1629685778,
        "expiration": 1629685838,
        "receiver": "08126666666",
        "message": "Your OTP is %s",
        "reference": "12345678901234567890",
        "param1": "100000",
        "param2": "1234567890",
        "param3": "987654",
        "param4": "674527846556468254"
    }
}

Parameter	Type	Description
command	String	Command for OTP-Pi
data	Object	Data for OTP-Pi
`data`.date_time	Number	Unix Time Stamp when the message is transmitted by the applications
`data`.receiver	String	MSISDN of the receiver
`data`.message	String	Content format of the SMS. Note that the format must be contains one %s
`data`.reference	String	Reference ID of the transaction. This value must match between `Create OTP` and `Validate OTP`
`data`.param1	String	Parameter 1. This value must match between `Create OTP` and `Validate OTP`
`data`.param2	String	Parameter 2. This value must match between `Create OTP` and `Validate OTP`
`data`.param3	String	Parameter 3. This value must match between `Create OTP` and `Validate OTP`
`data`.param4	String	Parameter 4. This value must match between `Create OTP` and `Validate OTP`

Create OTP Response

HTTP/1.1 200 OK
Host: sub.domain.tld
Connection: close
Content-type: application/json
Content-length: 199

{
    "command": "request-otp",
    "response_code": "0000",
    "data": {
        "date_time": 1629685778,
        "receiver": "08126666666",
        "reference": "12345678901234567890"
    }
}

Parameter	Type	Description
command	String	Command for OTP-Pi
response_code	String	Response Code
data	Object	Data for OTP-Pi
`data`.date_time	Number	Unix Time Stamp when the message is transmitted by the applications
`data`.receiver	String	MSISDN of the receiver
`data`.reference	String	Reference ID of the transaction. This value must match between `Create OTP` and `Validate OTP`

Validate OTP Request

POST /api/otp HTTP/1.1
Host: sub.domain.tld
Connection: close
User-agent: KSPS
Content-type: application/json
Content-length: 274
Authorization: Basic dXNlcjpwYXNzd29yZA==

{
    "command": "verify-otp",
    "data": {
        "date_time": 1629685778,
        "receiver": "08126666666",
        "otp": "123456",
        "reference": "12345678901234567890",
        "param1": "100000",
        "param2": "1234567890",
        "param3": "987654",
        "param4": "674527846556468254"
    }
}

Parameter	Type	Description
command	String	Command for OTP-Pi
data	Object	Data for OTP-Pi
`data`.date_time	Number	Unix Time Stamp when the message is transmitted by the applications
`data`.receiver	String	MSISDN of the receiver
`data`.otp	String	Cleat OTP to be valieadted
`data`.reference	String	Reference ID of the transaction. This value must match between `Create OTP` and `Validate OTP`
`data`.param1	String	Parameter 1. This value must match between `Create OTP` and `Validate OTP`
`data`.param2	String	Parameter 2. This value must match between `Create OTP` and `Validate OTP`
`data`.param3	String	Parameter 3. This value must match between `Create OTP` and `Validate OTP`
`data`.param4	String	Parameter 4. This value must match between `Create OTP` and `Validate OTP`

Validate OTP Response

HTTP/1.1 200 OK
Host: sub.domain.tld
Connection: close
Content-type: application/json
Content-length: 201

{
    "command": "verify-otp",
    "response_code": "0000",
    "data": {
        "date_time": 1629685778,
        "receiver": "08126666666",
        "reference": "12345678901234567890"
    }
}

Parameter	Type	Description
command	String	Command for OTP-Pi
response_code	String	Response Code
data	Object	Data for OTP-Pi
`data`.date_time	Number	Unix Time Stamp when the message is transmitted by the applications
`data`.receiver	String	MSISDN of the receiver
`data`.reference	String	Reference ID of the transaction. This value must match between `Create OTP` and `Validate OTP`

Send SMS Request

POST /api/sms HTTP/1.1
Host: sub.domain.tld
Connection: close
User-agent: KSPS
Content-type: application/json
Content-length: 182
Authorization: Basic dXNlcjpwYXNzd29yZA==

{
    "command": "send-sms",
    "data": {
        "date_time": 1629685778,
        "expiration": 1629685838,
        "id": 123456,
        "receiver": "08126666666",
        "message": "Your OTP is 1234"
    }
}

Parameter	Type	Description
command	String	Command for OTP-Pi
data	Object	Data for OTP-Pi
`data`.date_time	Number	Unix Time Stamp when the message is transmitted by the applications
`data`.id	String	SMS ID
`data`.reference	String	Reference ID of the transaction. This value must match between `Create OTP` and `Validate OTP`
`data`.receiver	String	MSISDN of the receiver
`data`.message	String	Content of the SMS

Send Email Request

POST /api/sms HTTP/1.1
Host: sub.domain.tld
Connection: close
User-agent: KSPS
Content-type: application/json
Content-length: 222
Authorization: Basic dXNlcjpwYXNzd29yZA==

{
    "command": "send-email",
    "data": {
        "date_time": 1629685778,
        "expiration": 1629685838,
        "id": 123456,
        "receiver": "someone@domain.tld",
        "subject": "Your OTP Code",
        "message": "Your OTP is 1234"
    }
}

Parameter	Type	Description
command	String	Command for OTP-Pi
data	Object	Data for OTP-Pi
`data`.date_time	Number	Unix Time Stamp when the message is transmitted by the applications
`data`.id	String	SMS ID
`data`.receiver	String	Recipient's email address
`data`.message	String	Content of the SMS

Block Number Request

POST /api/block HTTP/1.1
Host: sub.domain.tld
Connection: close
User-agent: KSPS
Content-type: application/json
Content-length: 107
Authorization: Basic dXNlcjpwYXNzd29yZA==

{
    "command": "block-msisdn",
    "data": {
        "date_time": 1629685778,
        "receiver": "08126666666"
    }
}

Parameter	Type	Description
command	String	Command for OTP-Pi
data	Object	Data for OTP-Pi
`data`.date_time	Number	Unix Time Stamp when the message is transmitted by the applications
`data`.msisdn	String	MSISDN number to block

Unblock Number Request

POST /api/unblock HTTP/1.1
Host: sub.domain.tld
Connection: close
User-agent: KSPS
Content-type: application/json
Content-length: 109
Authorization: Basic dXNlcjpwYXNzd29yZA==

{
    "command": "unblock-msisdn",
    "data": {
        "date_time": 1629685778,
        "receiver": "08126666666"
    }
}

Parameter	Type	Description
command	String	Command for OTP-Pi
data	Object	Data for OTP-Pi
`data`.date_time	Number	Unix Time Stamp when the message is transmitted by the applications
`data`.receiver	String	MSISDN number to be unblocked

Get Modem List Request

POST /api/modem HTTP/1.1
Host: sub.domain.tld
Connection: close
User-agent: KSPS
Content-type: application/json
Content-length: 87
Authorization: Basic dXNlcjpwYXNzd29yZA==

{
    "data": {
        "date_time": 1629685778
    },
    "command": "get-modem-list"
}

Get Modem List Response

HTTP/1.1 200 OK
Date: Sun, 18 Oct 2012 10:36:20 GMT
Server: Apache/2.2.14
Content-Length: 1192
Content-Type: text/html; charset=UTF-8
Connection: Closed

{
    "response_code": "0000",
    "data": {
        "modem_list": {
            "d740eb1f5e9799c2b50452ea5acf6054": {
                "internetConnected": false,
                "active": true,
                "imsi": "990106913401164",
                "smsCenter": "",
                "copsOperator": "TELKOMSEL",
                "connected": false,
                "iccid": "89621010691340116477",
                "defaultModem": true,
                "internetAccess": false,
                "port": "COM7",
                "name": "SIMCOM_SIM800L",
                "imei": "359848091599999",
                "id": "d740eb1f5e9799c2b50452ea5acf6054"
            },
            "20570ff7f9a4664df11e8c3dfdf4c6c4": {
                "internetConnected": false,
                "active": true,
                "imsi": "880106913401164",
                "smsCenter": "",
                "copsOperator": "TELKOMSEL",
                "connected": false,
                "iccid": "89621010691340116454",
                "defaultModem": false,
                "internetAccess": false,
                "port": "COM3",
                "name": "Huawei",
                "imei": "359848091599994",
                "id": "20570ff7f9a4664df11e8c3dfdf4c6c4"
            }
        }
    },
    "command": "get-modem-list"
}

USSD Command Request

Users can run USSD code via the API either using the REST API or using the message broker. When executing the USSD code, the user must submit the modem ID. The modem ID can be obtained using the API either using the REST API or using a message broker.

POST /api/ussd HTTP/1.1
Host: sub.domain.tld
Connection: close
User-agent: KSPS
Content-type: application/json
Content-length: 163
Authorization: Basic dXNlcjpwYXNzd29yZA==

{
    "data": {
        "date_time": 1629685778,
        "modem_id": "d740eb1f5e9799c2b50452ea5acf6054",
        "ussd_code": "*888#"
    },
    "command": "request-ussd"
}

USSD Command Response

HTTP/1.1 200 OK
Date: Sun, 18 Oct 2012 10:36:20 GMT
Server: Apache/2.2.14
Content-Length: 220
Content-Type: text/html; charset=UTF-8
Connection: Closed

{
    "data": {
        "date_time": 1629685778,
        "modem_id": "d740eb1f5e9799c2b50452ea5acf6054",
        "ussd_code": "*888#",
        "ussd_response": "Sisa pulsa Anda adalah Rp 12345"
    },
    "command": "request-ussd",
}

2. Authorization

OTP-Pi use Basic Authorization. Username and password required on each reaquest.

For more information, click https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Authorization

Scenario 2 - App Server Can't Access OTP-Pi

In this scenario, the App Server may send the OTP to RabbitMQ Server, Redis Server, Mosquitto Server, ActiveMQ Server or WSMessageBroker. WSMessageBroker uses the WebSoket protocol and Basic Authentication. Both App Server and OTP-Pi act as clients of WSMessageBroker.

In this scenario, the application cannot request the OTP-Pi to validate the previously sent OTP. Thus, the application must have its own OTP system. The application simply sends a message containing the OTP. The application must have a mechanism to validate the previously submitted OTP.

Another way is to use a separate OTP system from the application. It is this system that issues the OTP code so that it can validate the code if the application so desires.

App Server acts as publisher and OTP-Pi becomes consumer of RabbitMQ Server, Redis Server, Mosquitto Server, ActiveMQ Server or WSMessageBroker. Both must use the same topic so that all OTPs sent by the App Server can be received by the OTP-Pi.

From the two scenarios above, the OTP-Pi will send SMS using a GSM modem that is physically attached to the OTP-Pi device. Users can use either RabbitMQ Server, Redis Server, Mosquitto Server, ActiveMQ Server or WSMessageBroker can also use both at the same time. However, if the App Server sends the same OTP to RabbitMQ Server, Redis Server, Mosquitto Server, ActiveMQ Server or WSMessageBroker, the OTP-Pi will send the SMS twice to the recipient number.

In this scenario, the user does not need a public IP. Users only need:

OTP-Pi
Internet connection (no need for public IP and port forwarding)
RabbitMQ, Redis, Mosquitto, ActiveMQ, Stomp or WSMessageBroker servers

1. Message Format

Send SMS Request

{
    "command": "send-sms",
    "data": {
        "date_time": 1629685778,
        "expiration": 1629685838,
        "id": 123456,
        "receiver": "08126666666",
        "message": "Your OTP is 1234"
    }
}

Parameter	Type	Description
command	String	Command for OTP-Pi
data	Object	Data for OTP-Pi
`data`.date_time	Number	Unix Time Stamp when the message is transmitted by the applications
`data`.id	String	SMS ID
`data`.receiver	String	MSISDN of the receiver
`data`.message	String	Content of the SMS

Send Email Request

{
    "command": "send-email",
    "data": {
        "date_time": 1629685778,
        "expiration": 1629685838,
        "id": 123456,
        "receiver": "someone@domain.tld",
        "subject": "Your OTP Code",
        "message": "Your OTP is 1234"
    }
}

Parameter	Type	Description
command	String	Command for OTP-Pi
data	Object	Data for OTP-Pi
`data`.date_time	Number	Unix Time Stamp when the message is transmitted by the applications
`data`.id	String	SMS ID
`data`.receiver	String	Recipient's email address
`data`.message	String	Content of the SMS

Block Number Request

{
    "command": "block-msisdn",
    "data": {
        "date_time": 1629685778,
        "receiver": "08126666666",
    }
}

Parameter	Type	Description
command	String	Command for OTP-Pi
data	Object	Data for OTP-Pi
`data`.date_time	Number	Unix Time Stamp when the message is transmitted by the applications
`data`.receiver	String	MSISDN number to block

Unblock Number Request

{
    "command": "unblock-msisdn",
    "data": {
        "date_time": 1629685778,
        "receiver": "08126666666",
    }
}

Parameter	Type	Description
command	String	Command for OTP-Pi
data	Object	Data for OTP-Pi
`data`.date_time	Number	Unix Time Stamp when the message is transmitted by the applications
`data`.receiver	String	MSISDN number to be unblocked

Get Modem List Request

{
    "data": {
        "date_time": 1629685778
    },
    "command": "get-modem-list",
    "callback_topic": "random_topic",
    "callback_delay": 50
}

Get Modem List Response

{
    "response_code": "0000",
    "data": {
        "modem_list": {
            "d740eb1f5e9799c2b50452ea5acf6054": {
                "internetConnected": false,
                "active": true,
                "imsi": "990106913401164",
                "smsCenter": "",
                "copsOperator": "TELKOMSEL",
                "connected": false,
                "iccid": "89621010691340116477",
                "defaultModem": true,
                "internetAccess": false,
                "port": "COM7",
                "name": "SIMCOM_SIM800L",
                "imei": "359848091599999",
                "id": "d740eb1f5e9799c2b50452ea5acf6054"
            },
            "20570ff7f9a4664df11e8c3dfdf4c6c4": {
                "internetConnected": false,
                "active": true,
                "imsi": "880106913401164",
                "smsCenter": "",
                "copsOperator": "TELKOMSEL",
                "connected": false,
                "iccid": "89621010691340116454",
                "defaultModem": false,
                "internetAccess": false,
                "port": "COM3",
                "name": "Huawei",
                "imei": "359848091599994",
                "id": "20570ff7f9a4664df11e8c3dfdf4c6c4"
            }
        }
    },
    "command": "get-modem-list"
}

USSD Command Request

Users can run USSD code via the API either using the REST API or using the message broker. When executing the USSD code, the user must submit the modem ID. The modem ID can be obtained using the API either using the REST API or using a message broker.

{
    "data": {
        "date_time": 1629685778,
        "modem_id": "d740eb1f5e9799c2b50452ea5acf6054",
        "ussd_code": "*888#"
    },
    "command": "request-ussd",
    "callback_topic": "random_topic",
    "callback_delay": 50
}

USSD Command Response

{
    "data": {
        "date_time": 1629685778,
        "modem_id": "d740eb1f5e9799c2b50452ea5acf6054",
        "ussd_code": "*888#",
        "ussd_response": "Sisa pulsa Anda adalah Rp 12345"
    },
    "command": "request-ussd",
    "callback_topic": "random_topic",
    "callback_delay": 50
}

2. Websocket Handshakes

The handshake between OTP-Pi and WSMessageBroker is as follows:

OTP-Pi as client and WSMessageBroker as server
OTP-Pi sends request to WSMessageBroker

WebSocket Subscriber Configuration Example

Parameter	Value
Host	domain.example
Port	8000
Path	/ws
Username	username
Password	password
Topic	sms

Example of a WebSocket Handshake

GET /ws?topic=sms HTTP/1.1
Host: domain.example:8000
Authorization: Basic dXNlcm5hbWU6cGFzc3dvcmQ=
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
Sec-WebSocket-Version: 13

The server will verify whether the username and password are correct. If true, the server will add the connection to the list of recipients of the message.

When a client sends a message, the message will be sent to all clients by topic except the sender. Thus, the handshake between the sender and the recipient of the message is the same.

The OTP-Pi never sends messages to the WSMessageBroker server. OTP-Pi only accepts messages according to the desired topic.

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Name		Name	Last commit message	Last commit date
Latest commit History 721 Commits
.settings		.settings
USB Driver for Windows		USB Driver for Windows
jar		jar
resource		resource
src		src
.classpath		.classpath
.gitignore		.gitignore
.project		.project
OTP-Pi.jar		OTP-Pi.jar
OTP.postman_collection.json		OTP.postman_collection.json
README.md		README.md
config.ini		config.ini
content.md		content.md
ds3231.png		ds3231.png
env.md		env.md
feature-inbox.png		feature-inbox.png
full-diagram.png		full-diagram.png
full-topology.svg		full-topology.svg
full.png		full.png
installation.md		installation.md
newenv.md		newenv.md
otp-pi.png		otp-pi.png
prefix-based-routing.png		prefix-based-routing.png
ss-desktop.png		ss-desktop.png
ss-desktop2.png		ss-desktop2.png
ss-network-setting-dhcp.png		ss-network-setting-dhcp.png
ss-network-setting-ethernet.png		ss-network-setting-ethernet.png
ss-network-setting-wlan.png		ss-network-setting-wlan.png
support.png		support.png
usb-hub-20-port.png		usb-hub-20-port.png

kamshory/OTP-Pi

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OTP-Pi

No RDBMS Required

System Requirement

Features

Built-in Wifi

Multiple Method

Multiple Device

Device Inspector

Prefix-Based Routing

USSD Support

Manual SMS

Internet Mobile

Administrator Settings

API Settings

General Settings

Time Settings

API Users

Subscriber Settings

SMS Settings

Modem Settings

APN Settings for Indonesian Telco

Blocking List

Multiple Email Account

Bell Setting

DDNS Record

Cloudflare Account

No IP Account

Dynu Account

Afraid Account

Network Setting

DHCP

Wireless LAN

Ethernet

Firewalls

Monitor

SMS Inbox

IMEI Tool

SIM Tool

Real Time Clock

Reset Device

Topology

Scenario 1 - App Server Can Access OTP-Pi

Scenario 2 - App Server Can't Access OTP-Pi

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