Method decrypt

modules/crypt/etc/gcm.js:72–75

(data, buf)

		return buf;
	};
	decrypt(data, buf) {
		this.ghash.update(data);
		return this.ctr.decrypt(data, buf);
	};
	close() {
		let t = this.ghash.close();
		return Bin.xor(t, this.block.encrypt(this.y0));