feature: add secured message

- encrypt/decrypt every message (require ^0.0.2)

Signed-off-by: pakintada@gmail.com <Pakin>

src/lib/core/utils/crypto.ts

@@ -0,0 +1,68 @@
+export class WebCryptoHelper {
+	static async generateKeyPair() {
+		const keyPair = await window.crypto.subtle.generateKey(
+			{
+				name: 'ECDH',
+				namedCurve: 'P-256'
+			},
+			true,
+			['deriveKey', 'deriveBits']
+		);
+
+		const exportedPublic = await window.crypto.subtle.exportKey('raw', keyPair.publicKey);
+		const publicKeyBase64 = btoa(String.fromCharCode(...new Uint8Array(exportedPublic)));
+
+		return { privateKey: keyPair.privateKey, publicKeyBase64 };
+	}
+
+	static async deriveSharedKey(clientPrivateKey: any, serverPublicKeyBase64: any) {
+		const binarySign = atob(serverPublicKeyBase64);
+		const bytes = new Uint8Array(binarySign.length);
+		for (let i = 0; i < binarySign.length; i++) {
+			bytes[i] = binarySign.charCodeAt(i);
+		}
+
+		const importedServerPublic = await window.crypto.subtle.importKey(
+			'raw',
+			bytes,
+			{ name: 'ECDH', namedCurve: 'P-256' },
+			true,
+			[]
+		);
+		return await window.crypto.subtle.deriveKey(
+			{ name: 'ECDH', public: importedServerPublic },
+			clientPrivateKey,
+			{ name: 'AES-GCM', length: 256 },
+			true,
+			['encrypt', 'decrypt']
+		);
+	}
+
+	static async decryptMessage(aesKey: any, ciphertextBase64: any, ivBase64: any) {
+		const rawCipher = Uint8Array.from(atob(ciphertextBase64), (c) => c.charCodeAt(0));
+		const rawIv = Uint8Array.from(atob(ivBase64), (c) => c.charCodeAt(0));
+		const decryptedBuffer = await window.crypto.subtle.decrypt(
+			{ name: 'AES-GCM', iv: rawIv },
+			aesKey,
+			rawCipher
+		);
+		return new TextDecoder().decode(decryptedBuffer);
+	}
+
+	// Encrypt outgoing messages before sending them to your Axum backend
+	static async encryptMessage(aesKey: any, plainText: any) {
+		const iv = window.crypto.getRandomValues(new Uint8Array(12)); // 12-byte nonce
+		const encodedText = new TextEncoder().encode(plainText);
+
+		const ciphertextBuffer = await window.crypto.subtle.encrypt(
+			{ name: 'AES-GCM', iv: iv },
+			aesKey,
+			encodedText
+		);
+
+		const ciphertextBase64 = btoa(String.fromCharCode(...new Uint8Array(ciphertextBuffer)));
+		const ivBase64 = btoa(String.fromCharCode(...iv));
+
+		return { ciphertext: ciphertextBase64, iv: ivBase64 };
+	}
+}