Payment Key Utility | Offline TDES KCV Calculator

Project Description

Payment Key Utility is an offline browser-based tool designed to support payment operations, implementation, and troubleshooting teams.

The application calculates Key Check Values (KCVs), compares values from payment terminals and host systems, and checks common key properties through a practical interface. All calculations run locally in the browser without a backend or external network requests.

Key Features

KCV calculation for 16-byte and 24-byte TDES keys.

Configurable KCV output lengths and comparison against an expected value.

Device-to-host KCV comparison, with separate handling for matches, mismatches, and different value lengths.

Hexadecimal input validation, odd-parity checks, and detection of known weak or degenerate key components.

XOR combination of two or three test key components, followed by KCV calculation.

Guided PIN troubleshooting using operational information such as KCVs, key indexes, request delivery, and PIN block format.

Masked key inputs, configurable clearing after inactivity, and TXT reports that exclude keys and components.

Built-in calculation self-tests and a responsive Arabic interface with embedded Cairo typography.

Project Scope

Requirements analysis, payment workflow design, interface implementation, input validation, and calculation checks using known test vectors.

The project demonstrates how payment operations experience can be translated into a focused software utility that supports technical investigation and reduces repetitive manual checks.