encrypt.js

	JWE_ALG:              'A256KW',
	JWE_ENC:              'A256CBC-HS512',
	ENCRYPTION_ALGORITHM: "AES-CBC",
	IV_LENGTH:            16,
	KEY_LENGTH:           32,
	W3C_RSA_ALGORITHM: {
		name: "RSASSA-PKCS1-v1_5",
		modulusLength: 2048,
		publicExponent: new Uint8Array([1, 0, 1]),
		hash: { name: "SHA-256" },
	},
	KEY_OPS: ["sign", "verify"],




	const encrypt = async ({ plaintext }) => {
		const header = {
			alg: JWE_ALG,
			enc: JWE_ENC,
		};
		const ivBuffer = window.crypto.getRandomValues(Buffer(IV_LENGTH));
		const cryptoKey = await window.crypto.subtle.generateKey({ 
				name: ENCRYPTION_ALGORITHM,
				length: KEY_LENGTH * 8
			},
			true,
			["encrypt", "decrypt"]
		);
		const keyBuffer = await window.crypto.subtle.exportKey("raw", cryptoKey);
		const key = Buffer.from(keyBuffer).toString("base64");
		const encrypted = await window.crypto.subtle.encrypt(
			{
			  name: ENCRYPTION_ALGORITHM,
			  iv: ivBuffer
			},
			cryptoKey,
			Buffer.from(plaintext, 'utf8')
		  );
		const ciphertext = base64url(encrypted);
		const protectedHeader = base64url(JSON.stringify(header))
		const iv = base64url(ivBuffer)
		const jwe = { 
			protected: protectedHeader, 
			iv, 
			ciphertext 
		};
		return { jwe, key }
	}