⚡ StegoShield Gateway ⚡

Blocking & Detecting Hidden Malicious Data Inside Images

A Spring Boot Security Gateway for Detecting LSB-Based Steganography Before Image Delivery

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⚡ Technology Stack ⚡

Category	Technology	Purpose
Programming Language	Java 17	Core application development
Framework	Spring Boot	REST API & Security Gateway
Build Tool	Maven	Dependency management and project build
Image Processing	BufferedImage, ImageIO	Read and analyze uploaded images
Steganography Detection	Least Significant Bit (LSB)	Extract hidden binary information
Entropy Analysis	Shannon Entropy	Detect suspicious randomness
Signature Detection	Binary Signature Scanner	Detect embedded ZIP, EXE, ELF, PDF and more
Payload Analysis	Payload Reconstruction	Decode and inspect extracted payload
Database	PostgreSQL / H2	Store logs and application data
API Testing	Postman	REST API testing and validation
Logging	SLF4J / Logback	Security monitoring and application logs
Version Control	Git & GitHub	Source code management

Phase 01 • Existing Chat Application Workflow

flowchart LR

A["User A"]
B["Upload Image"]
C["Chat Server"]
D["Store Image"]
E["Forward Image"]
F["User B"]

A --> B
B --> C
C --> D
D --> E
E --> F

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Phase 02 • What Happens With a Malicious Image?

flowchart LR

A["Attacker"]

B["Image with Hidden LSB Payload"]

C["Chat Server"]

D["Image Stored"]

E["Image Delivered"]

F["Victim"]

A --> B
B --> C
C --> D
D --> E
E --> F

style B fill:#ff4d4d,color:#000000,stroke:#b30000,stroke-width:3px
style C fill:#ffe6e6,color:#000000
style D fill:#ffe6e6,color:#000000
style E fill:#ffe6e6,color:#000000
style F fill:#ff4d4d,color:#000000,stroke:#b30000,stroke-width:3px

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Phase 03 • StegoShield Solution

flowchart LR

A["User A"]

B["Upload Image"]

C["StegoShield Gateway"]

D["Security Analysis"]

E{"Image Safe?"}

F["Forward Image"]

G["Reject Upload"]

H["User B"]

A --> B
B --> C
C --> D
D --> E

E -->|YES| F
F --> H

E -->|NO| G

style F fill:#90EE90,color:#000000
style G fill:#ff6666,color:#000000

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Phase 04 • Complete System Architecture

flowchart TD

UA["Sender"]

UPLOAD["Upload API"]

GATEWAY["StegoShield Gateway"]

BUFFER["BufferedImage Reader"]

LSB["LSB Analyzer"]

ENTROPY["Entropy Calculator"]

SIGNATURE["Binary Signature Scanner"]

PAYLOAD["Payload Decoder"]

ENGINE["Decision Engine"]

ALLOW["Forward Image"]

BLOCK["Reject Upload"]

LOG["Security Log"]

USERB["Receiver"]

UA --> UPLOAD
UPLOAD --> GATEWAY

GATEWAY --> BUFFER

BUFFER --> LSB
BUFFER --> ENTROPY
BUFFER --> SIGNATURE
BUFFER --> PAYLOAD

LSB --> ENGINE
ENTROPY --> ENGINE
SIGNATURE --> ENGINE
PAYLOAD --> ENGINE

ENGINE -->|Safe| ALLOW
ENGINE -->|Malicious| BLOCK

ALLOW --> USERB

ENGINE --> LOG
BLOCK --> LOG

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Phase 05 • Image Analysis Pipeline

flowchart TD

A["Image Upload"]

B["Validate Request"]

C["Read Image (BufferedImage)"]

D["Extract Pixels"]

E["Extract RGB Values"]

F["Extract Least Significant Bits"]

G["Generate Bit Stream"]

H["Calculate Shannon Entropy"]

I["Scan Binary Signatures"]

J["Attempt Payload Reconstruction"]

K["Generate Analysis Report"]

A --> B
B --> C
C --> D
D --> E
E --> F
F --> G
G --> H
H --> I
I --> J
J --> K

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Phase 06 • Detection Engine

flowchart TD

IMG["Uploaded Image"]

LSB["LSB Score"]

ENT["Entropy Score"]

SIG["Signature Detection"]

PAY["Payload Confidence"]

IMG --> LSB
IMG --> ENT
IMG --> SIG
IMG --> PAY

LSB --> SCORE

ENT --> SCORE

SIG --> SCORE

PAY --> SCORE

SCORE["Combined Risk Score"]

SCORE --> DECISION{"Risk Threshold"}

DECISION -->|Low| SAFE["Safe"]

DECISION -->|High| MAL["Malicious"]

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Phase 07 • Decision Logic

flowchart TD

START["Image Uploaded"]

LSB["LSB Analysis"]

ENTROPY["Entropy Analysis"]

SIGNATURE["Signature Detection"]

PAYLOAD["Payload Reconstruction"]

START --> LSB
START --> ENTROPY
START --> SIGNATURE
START --> PAYLOAD

LSB --> SCORE

ENTROPY --> SCORE

SIGNATURE --> SCORE

PAYLOAD --> SCORE

SCORE["Risk Score"]

SCORE --> THRESHOLD{"Threshold"}

THRESHOLD -->|Low Risk| ALLOW["Allow Upload"]

THRESHOLD -->|High Risk| REJECT["Reject Upload"]

style ALLOW fill:#90EE90,color:#000000
style REJECT fill:#ff6666,color:#000000

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Phase 08 • Internal Processing Workflow

sequenceDiagram

participant Sender

participant Gateway

participant Analyzer

participant DecisionEngine

participant Receiver

Sender->>Gateway: Upload Image

Gateway->>Analyzer: Read BufferedImage

Analyzer->>Analyzer: Extract Pixel Data

Analyzer->>Analyzer: LSB Extraction

Analyzer->>Analyzer: Entropy Analysis

Analyzer->>Analyzer: Signature Detection

Analyzer->>Analyzer: Payload Reconstruction

Analyzer->>DecisionEngine: Analysis Report

DecisionEngine-->>Gateway: SAFE

Gateway-->>Receiver: Deliver Image

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Phase 09 • Threat Detection & Temporary Blocking Workflow

flowchart TD

A["Threat Detected"] --> B["Reject Upload"]

B --> C["Store Security Log"]

C --> D["Increment User Violation Count"]

D --> E["Temporarily Block User Uploads<br/>(3 Minutes)"]

E --> F["Block Timer Starts"]

F --> G{"3 Minutes Completed?"}

G -->|No| H["Keep User Blocked"]

H --> F

G -->|Yes| I["Restore Upload Access"]

I --> J["User Can Upload Again"]

style A fill:#ff6666,color:#000000,stroke:#b30000,stroke-width:2px
style B fill:#ff9999,color:#000000
style C fill:#ffe699,color:#000000
style D fill:#ffd966,color:#000000
style E fill:#ff4d4d,color:#000000,stroke:#b30000,stroke-width:2px
style I fill:#90EE90,color:#000000
style J fill:#90EE90,color:#000000

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⚡ Images ⚡

• Payload Image Creation	• Payload Incident Data
• Block Status View	• Payload Detection Result
• Temporary User Blocking	• Clean Image Detection
• PostgreSQL Incident Database	• Incident Log API
• Security Report API	• Scan Result Summary
• Frontend Integration