devdunia/caesar-cipher.html at main · echobash/devdunia · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link rel="icon" type="image/png" href="images/logo.png">
    <link rel="apple-touch-icon" href="images/logo.png">
    <meta name="description" content="Encode and decode text using Caesar cipher with custom shift values. Free online Caesar cipher encoder/decoder for developers.">
    <script src="https://cdn.tailwindcss.com"></script>
    <script src="js/common.js"></script>
    <style>
        body {
            background: linear-gradient(135deg, #0f172a 0%, #1e293b 50%, #0f172a 100%);
        }
    </style>
</head>
<body class="h-screen lg:ml-72">
    <!-- Background: Consistent Subtle Dark Gradient -->
    <div class="fixed inset-0 -z-10 bg-gradient-to-br from-gray-900 via-slate-900 to-gray-900"></div>

    <!-- Main Container -->
    <div class="main-content">
        <div class="relative z-10 container mx-auto px-4 pt-16 pb-24 sm:px-6 lg:px-8">

        <!-- Page Header -->
        <div class="text-center mb-12">
            <h1 class="text-3xl sm:text-4xl font-bold mb-4 tracking-tight
                       text-transparent bg-clip-text bg-gradient-to-r from-blue-400 to-cyan-500">
                Caesar Cipher
            </h1>
            <p class="text-lg text-gray-400 max-w-2xl mx-auto">
                Encode and decode text using Caesar cipher with custom shift values. One of the oldest encryption methods.
            </p>
        </div>

        <!-- Tool Container -->
        <div class="max-w-4xl mx-auto">
            <div class="bg-slate-800/70 backdrop-blur-md rounded-lg shadow-lg border border-slate-700/60 p-6">

                <!-- Shift Value Input -->
                <div class="mb-6">
                    <label for="shift-value" class="block text-sm font-medium text-gray-300 mb-2">
                        Shift Value (1-25)
                    </label>
                    <input
                        type="number"
                        id="shift-value"
                        min="1"
                        max="25"
                        value="3"
                        class="w-32 px-4 py-2 bg-slate-700/50 border border-slate-600 rounded-lg text-gray-200 focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent"
                    >
                    <p class="text-xs text-gray-500 mt-1">Enter the number of positions to shift each letter</p>
                </div>

                <!-- Input Section -->
                <div class="mb-6">
                    <label for="input-text" class="block text-sm font-medium text-gray-300 mb-2">
                        Input Text
                    </label>
                    <textarea
                        id="input-text"
                        rows="6"
                        class="w-full px-4 py-3 bg-slate-700/50 border border-slate-600 rounded-lg text-gray-200 placeholder-gray-400 focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent resize-none font-mono text-sm"
                        placeholder="Enter text to encode or decode with Caesar cipher..."
                    ></textarea>
                </div>

                <!-- Action Buttons -->
                <div class="flex flex-wrap gap-3 mb-6">
                    <button id="encode-btn" class="px-6 py-3 bg-blue-600 hover:bg-blue-700 text-white font-medium rounded-lg transition-colors duration-200 flex items-center space-x-2">
                        <svg class="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
                            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M12 15v2m-6 4h12a2 2 0 002-2v-6a2 2 0 00-2-2H6a2 2 0 00-2 2v6a2 2 0 002 2zm10-10V7a4 4 0 00-8 0v4h8z"></path>
                        </svg>
                        <span>Encode</span>
                    </button>

                    <button id="decode-btn" class="px-6 py-3 bg-green-600 hover:bg-green-700 text-white font-medium rounded-lg transition-colors duration-200 flex items-center space-x-2">
                        <svg class="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
                            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M8 11V7a4 4 0 118 0m-4 8v2m-6 4h12a2 2 0 002-2v-6a2 2 0 00-2-2H6a2 2 0 00-2 2v6a2 2 0 002 2z"></path>
                        </svg>
                        <span>Decode</span>
                    </button>

                    <button id="brute-force-btn" class="px-6 py-3 bg-purple-600 hover:bg-purple-700 text-white font-medium rounded-lg transition-colors duration-200 flex items-center space-x-2">
                        <svg class="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
                            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M9 12l2 2 4-4m6 2a9 9 0 11-18 0 9 9 0 0118 0z"></path>
                        </svg>
                        <span>Brute Force (All Shifts)</span>
                    </button>

                    <button class="clear-btn px-6 py-3 bg-slate-600 hover:bg-slate-700 text-white font-medium rounded-lg transition-colors duration-200 flex items-center space-x-2">
                        <svg class="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
                            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M19 7l-.867 12.142A2 2 0 0116.138 21H7.862a2 2 0 01-1.995-1.858L5 7m5 4v6m4-6v6m1-10V4a1 1 0 00-1-1h-4a1 1 0 00-1 1v3M4 7h16"></path>
                        </svg>
                        <span>Clear All</span>
                    </button>
                </div>

                <!-- Output Section -->
                <div id="output-section" class="hidden">
                    <label for="output-text" class="block text-sm font-medium text-gray-300 mb-2">
                        Result
                    </label>
                    <div class="relative">
                        <textarea
                            id="output-text"
                            rows="6"
                            class="w-full px-4 py-3 bg-slate-700/50 border border-slate-600 rounded-lg text-gray-200 focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent resize-none font-mono text-sm"
                            readonly
                        ></textarea>

                        <!-- Copy Button -->
                        <button class="copy-btn absolute top-2 right-2 px-3 py-1 bg-slate-600 hover:bg-slate-700 text-white text-sm rounded transition-colors duration-200 flex items-center space-x-1" data-target="output-text">
                            <svg class="w-4 h-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
                                <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M8 16H6a2 2 0 01-2-2V6a2 2 0 012-2h8a2 2 0 012 2v8a2 2 0 01-2 2h-2m-6-4l2 2m0 0l2-2m-2 2V10"></path>
                            </svg>
                            <span>Copy</span>
                        </button>
                    </div>
                </div>

                <!-- Info Section -->
                <div class="mt-8 p-4 bg-slate-700/30 rounded-lg border border-slate-600/50">
                    <h3 class="text-lg font-semibold text-blue-400 mb-3">About Caesar Cipher</h3>
                    <div class="text-sm text-gray-300 space-y-2">
                        <p>The Caesar cipher is one of the simplest and most widely known encryption techniques. It's a type of substitution cipher where each letter in the plaintext is shifted a certain number of places down the alphabet.</p>
                        <p><strong>Key features:</strong></p>
                        <ul class="list-disc list-inside ml-4 space-y-1">
                            <li>Uses a fixed shift value (1-25)</li>
                            <li>Only affects letters A-Z and a-z</li>
                            <li>Numbers, symbols, and spaces remain unchanged</li>
                            <li>Can be easily broken with frequency analysis</li>
                            <li>ROT13 is a special case with shift value 13</li>
                        </ul>
                    </div>
                </div>

                <!-- Examples Section -->
                <div class="mt-6 p-4 bg-slate-700/30 rounded-lg border border-slate-600/50">
                    <h3 class="text-lg font-semibold text-blue-400 mb-3">Examples</h3>
                    <div class="grid grid-cols-1 md:grid-cols-2 gap-4 text-sm">
                        <div>
                            <p class="text-gray-300 font-medium mb-2">Encoding (Shift 3):</p>
                            <p class="text-gray-400">Hello World</p>
                            <p class="text-gray-500">→ Khoor Zruog</p>
                        </div>
                        <div>
                            <p class="text-gray-300 font-medium mb-2">Decoding (Shift 3):</p>
                            <p class="text-gray-400">Khoor Zruog</p>
                            <p class="text-gray-500">→ Hello World</p>
                        </div>
                    </div>
                </div>

            </div>
        </div>

    </div>

       <!-- Footer include -->
    <div id="footer"></div>
    <script>
    fetch("footer.html")
    .then(response => response.text())
    .then(data => {
        document.getElementById("footer").innerHTML = data;
    })
    .catch(err => console.error("Failed to load footer:", err));
    </script>

    <script>
        document.addEventListener('DOMContentLoaded', function() {
            const inputText = document.getElementById('input-text');
            const outputText = document.getElementById('output-text');
            const shiftValue = document.getElementById('shift-value');
            const encodeBtn = document.getElementById('encode-btn');
            const decodeBtn = document.getElementById('decode-btn');
            const bruteForceBtn = document.getElementById('brute-force-btn');
            const outputSection = document.getElementById('output-section');

            // Encode Caesar cipher
            encodeBtn.addEventListener('click', function() {
                const input = inputText.value.trim();
                const shift = parseInt(shiftValue.value);

                if (!input) {
                    alert('Please enter some text to encode');
                    return;
                }

                if (shift < 1 || shift > 25) {
                    alert('Shift value must be between 1 and 25');
                    return;
                }

                try {
                    const encoded = caesarCipher(input, shift);
                    outputText.value = encoded;
                    showOutput();
                } catch (error) {
                    alert('Error encoding text: ' + error.message);
                }
            });

            // Decode Caesar cipher
            decodeBtn.addEventListener('click', function() {
                const input = inputText.value.trim();
                const shift = parseInt(shiftValue.value);

                if (!input) {
                    alert('Please enter some text to decode');
                    return;
                }

                if (shift < 1 || shift > 25) {
                    alert('Shift value must be between 1 and 25');
                    return;
                }

                try {
                    const decoded = caesarCipher(input, -shift);
                    outputText.value = decoded;
                    showOutput();
                } catch (error) {
                    alert('Error decoding text: ' + error.message);
                }
            });

            // Brute force all shifts
            bruteForceBtn.addEventListener('click', function() {
                const input = inputText.value.trim();

                if (!input) {
                    alert('Please enter some text to brute force');
                    return;
                }

                try {
                    let result = 'Brute Force Results (All 25 possible shifts):\n\n';

                    for (let shift = 1; shift <= 25; shift++) {
                        const decoded = caesarCipher(input, -shift);
                        result += `Shift ${shift.toString().padStart(2, ' ')}: ${decoded}\n`;
                    }

                    outputText.value = result;
                    showOutput();
                } catch (error) {
                    alert('Error brute forcing: ' + error.message);
                }
            });

            // Helper functions
            function showOutput() {
                outputSection.classList.remove('hidden');
            }

            function caesarCipher(str, shift) {
                return str.replace(/[a-zA-Z]/g, function(char) {
                    const charCode = char.charCodeAt(0);
                    const offset = charCode <= 90 ? 65 : 97; // 'A' or 'a'
                    const shifted = ((charCode - offset + shift) % 26 + 26) % 26;
                    return String.fromCharCode(shifted + offset);
                });
            }

            // Example on page load
            window.addEventListener('load', () => {
                inputText.value = 'Hello World! This is a Caesar cipher example.';
            });
        });
    </script>
        </div>
    </div>

    <!-- Include Final Sidebar -->
    <div id="sidebar-container"></div>
    <script>
        // Load final_sidebar.html content
        fetch('final_sidebar.html')
            .then(response => response.text())
            .then(html => {
                document.getElementById('sidebar-container').innerHTML = html;
            })
            .catch(error => {
                console.error('Error loading sidebar:', error);
            });
    </script>
</body>
</html>