Are all binary-additive stream ciphers reciprocal? I'm writing a thesis focused on Maurer's provably-secure stream cipher. Long story short, this cipher works by expanding a short key into a long keystream and then XORring this keystream with the plaintext in order to obtain the ciphertext (and vicecersa).

Take this definition of a binary-additive stream cipher: a cipher where the plaintext, ciphertext and keystream are binary strings and where the ciphertext is produced as a XOR addition of the plaintext and the keystream.

Also, take this definition of a reciprocal cipher: a cipher in which the encryption and decryption algorithms are identical (they're the same involution).

With these two definitions, can I state that binary-additive stream ciphers are all reciprocal ciphers? I think so, since if the ciphertext is the XOR of plaintext and keystream, than the plaintext must be the XOR of the keystream and the ciphertext.
Since additive stream ciphers are involutions, i.e.,
$$
E_K(\cdot)=D_K(\cdot)
$$
for all possible keys $K$,
they are also reciprocal.