I know that for Poly1305-ChaCha20 reusing the key does reveal information about the plaintext. How it is for the Poly1305 MAC algorithm? Revealing information about the plaintext is not a problem at all, as it is available in plaintext anyways.
Question: Does a reuse of the Mac key reveal information about the key itself ?
Source: https://tools.ietf.org/html/rfc8103https://www.rfc-editor.org/rfc/rfc8103