Integrity Checksum

Overview

The IntegrityChecksum class generates SHA-256 checksums for payment data to ensure data integrity and prevent tampering. This is particularly useful for inline payment implementations where you need to verify that payment parameters haven’t been modified.

Class: IntegrityChecksum

package com.github.theresasogunle;

public class IntegrityChecksum

Methods

integrityChecksum()

Generates an integrity checksum for the payment data.

public String integrityChecksum()

Returns: String - A Base64-encoded SHA-256 hash of the payment parameters Description: This method creates a secure checksum by:

Collecting all payment parameters into a HashMap
Sorting the parameter keys alphabetically
Concatenating all values in sorted order
Appending the secret key
Generating a SHA-256 hash of the concatenated string
Encoding the hash in Base64

The resulting checksum can be used to verify that payment data hasn’t been tampered with during transmission.

Parameters Required

Before calling this method, set all required payment parameters:

amount

String

required

The transaction amount

payment_method

String

required

The payment method (e.g., “card”, “account”)

custom_description

String

Custom description for the transaction

custom_logo

String

URL to custom logo for payment page

country

String

required

Country code (e.g., “NG”, “GH”, “KE”)

currency

String

required

Currency code (e.g., “NGN”, “USD”, “GHS”)

customer_email

String

required

Customer’s email address

customer_firstname

String

required

Customer’s first name

customer_lastname

String

required

Customer’s last name

customer_phone

String

required

Customer’s phone number

txref

String

required

Your unique transaction reference

Example

IntegrityChecksum checksum = new IntegrityChecksum();

checksum.setAmount("5000")
        .setPayment_method("card")
        .setCustom_description("Payment for services")
        .setCountry("NG")
        .setCurrency("NGN")
        .setCustomer_email("customer@example.com")
        .setCustomer_firstname("John")
        .setCustomer_lastname("Doe")
        .setCustomer_phone("+2348012345678")
        .setTxref("TXN-" + System.currentTimeMillis());

String hash = checksum.integrityChecksum();
System.out.println("Checksum: " + hash);

Setter Methods

All setter methods return the IntegrityChecksum instance for method chaining.

setAmount()

Sets the transaction amount.

public IntegrityChecksum setAmount(String amount)

amount

String

required

The transaction amount

Returns: IntegrityChecksum - Returns the instance for method chaining

setPayment_method()

Sets the payment method.

public IntegrityChecksum setPayment_method(String payment_method)

payment_method

String

required

The payment method (e.g., “card”, “account”, “ussd”)

Returns: IntegrityChecksum - Returns the instance for method chaining

setCustom_description()

Sets a custom description for the transaction.

public IntegrityChecksum setCustom_description(String custom_description)

custom_description

String

Custom transaction description

Returns: IntegrityChecksum - Returns the instance for method chaining

setCustom_logo()

Sets a custom logo URL for the payment page.

public IntegrityChecksum setCustom_logo(String custom_logo)

custom_logo

String

URL to the custom logo image

Returns: IntegrityChecksum - Returns the instance for method chaining

setCountry()

Sets the country code.

public IntegrityChecksum setCountry(String country)

country

String

required

ISO country code (e.g., “NG”, “GH”, “KE”, “ZA”)

Returns: IntegrityChecksum - Returns the instance for method chaining

setCurrency()

Sets the transaction currency.

public IntegrityChecksum setCurrency(String currency)

currency

String

required

Currency code (e.g., “NGN”, “USD”, “GHS”, “KES”)

Returns: IntegrityChecksum - Returns the instance for method chaining

setCustomer_email()

Sets the customer’s email address.

public IntegrityChecksum setCustomer_email(String customer_email)

customer_email

String

required

Customer’s email address

Returns: IntegrityChecksum - Returns the instance for method chaining

setCustomer_firstname()

Sets the customer’s first name.

public IntegrityChecksum setCustomer_firstname(String customer_firstname)

customer_firstname

String

required

Customer’s first name

Returns: IntegrityChecksum - Returns the instance for method chaining

setCustomer_lastname()

Sets the customer’s last name.

public IntegrityChecksum setCustomer_lastname(String customer_lastname)

customer_lastname

String

required

Customer’s last name

Returns: IntegrityChecksum - Returns the instance for method chaining

setCustomer_phone()

Sets the customer’s phone number.

public IntegrityChecksum setCustomer_phone(String customer_phone)

customer_phone

String

required

Customer’s phone number with country code

Returns: IntegrityChecksum - Returns the instance for method chaining

setTxref()

Sets the unique transaction reference.

public IntegrityChecksum setTxref(String txref)

txref

String

required

Your unique transaction reference

Returns: IntegrityChecksum - Returns the instance for method chaining

Getter Methods

getAmount()

public String getAmount()

Returns: String - The transaction amount

getPayment_method()

public String getPayment_method()

Returns: String - The payment method

getCustom_description()

public String getCustom_description()

Returns: String - The custom description

getCustom_logo()

public String getCustom_logo()

Returns: String - The custom logo URL

getCountry()

public String getCountry()

Returns: String - The country code

getCurrency()

public String getCurrency()

Returns: String - The currency code

getCustomer_email()

public String getCustomer_email()

Returns: String - The customer’s email

getCustomer_firstname()

public String getCustomer_firstname()

Returns: String - The customer’s first name

getCustomer_lastname()

public String getCustomer_lastname()

Returns: String - The customer’s last name

getCustomer_phone()

public String getCustomer_phone()

Returns: String - The customer’s phone number

getTxref()

public String getTxref()

Returns: String - The transaction reference

How It Works

The integrity checksum algorithm:

Collects Parameters: All payment parameters including PBFPubKey are added to a HashMap
Sorts Keys: Parameter keys are sorted alphabetically
Concatenates Values: Values are concatenated in the sorted key order
Appends Secret: The secret key is appended to the concatenated string
Hashes: SHA-256 hash is generated from the final string
Encodes: The hash is Base64-encoded for transmission

The checksum includes your public key (PBFPubKey) and uses your secret key (SECKEY) in the hashing process. Ensure both are properly configured in RaveConstant.

Use Cases

Inline Payments: Verify payment data integrity when using Flutterwave’s inline JavaScript
Webhook Validation: Verify that webhook data hasn’t been tampered with
Payment Form Security: Ensure payment form data remains unchanged during submission

Complete Example

import com.github.theresasogunle.IntegrityChecksum;

public class PaymentChecksum {
    public static void main(String[] args) {
        // Create checksum instance
        IntegrityChecksum checksum = new IntegrityChecksum();
        
        // Set all required parameters
        checksum.setAmount("10000")
                .setPayment_method("card")
                .setCustom_description("Premium subscription")
                .setCustom_logo("https://example.com/logo.png")
                .setCountry("NG")
                .setCurrency("NGN")
                .setCustomer_email("john.doe@example.com")
                .setCustomer_firstname("John")
                .setCustomer_lastname("Doe")
                .setCustomer_phone("+2348012345678")
                .setTxref("TXN-" + System.currentTimeMillis());
        
        // Generate checksum
        String integrityHash = checksum.integrityChecksum();
        
        System.out.println("Integrity Hash: " + integrityHash);
        
        // Use this hash in your inline payment script
    }
}

The integrity checksum must be generated server-side to keep your secret key secure. Never expose your secret key in client-side code.

Core Classes

Transaction Classes

Utility Classes

Configuration

Overview

Class: IntegrityChecksum

Methods

integrityChecksum()

Parameters Required

Example

Setter Methods

setAmount()

setPayment_method()

setCustom_description()

setCustom_logo()

setCountry()

setCurrency()

setCustomer_email()

setCustomer_firstname()

setCustomer_lastname()

setCustomer_phone()

setTxref()

Getter Methods

getAmount()

getPayment_method()

getCustom_description()

getCustom_logo()

getCountry()

getCurrency()

getCustomer_email()

getCustomer_firstname()

getCustomer_lastname()

getCustomer_phone()

getTxref()

How It Works

Use Cases

Complete Example

Build docs developers (and LLMs) love

Core Classes

Transaction Classes

Utility Classes

Configuration

Documentation Index

​Overview

​Class: IntegrityChecksum

​Methods

​integrityChecksum()

​Parameters Required

​Example

​Setter Methods

​setAmount()

​setPayment_method()

​setCustom_description()

​setCustom_logo()

​setCountry()

​setCurrency()

​setCustomer_email()

​setCustomer_firstname()

​setCustomer_lastname()

​setCustomer_phone()

​setTxref()

​Getter Methods

​getAmount()

​getPayment_method()

​getCustom_description()

​getCustom_logo()

​getCountry()

​getCurrency()

​getCustomer_email()

​getCustomer_firstname()

​getCustomer_lastname()

​getCustomer_phone()

​getTxref()

​How It Works

​Use Cases

​Complete Example

Build docs developers (and LLMs) love

Overview

Class: IntegrityChecksum

Methods

integrityChecksum()

Parameters Required

Example

Setter Methods

setAmount()

setPayment_method()

setCustom_description()

setCustom_logo()

setCountry()

setCurrency()

setCustomer_email()

setCustomer_firstname()

setCustomer_lastname()

setCustomer_phone()

setTxref()

Getter Methods

getAmount()

getPayment_method()

getCustom_description()

getCustom_logo()

getCountry()

getCurrency()

getCustomer_email()

getCustomer_firstname()

getCustomer_lastname()

getCustomer_phone()

getTxref()

How It Works

Use Cases

Complete Example