SIV (Synthetic Initialization Vector)
An AEAD mode that derives its IV from the message itself, so a repeated nonce does not completely destroy security.
SIV was presented by Rogaway and Shrimpton in 2006 and standardised in RFC 5297 in 2008. The IV is computed as a PRF over the plaintext and the associated data, which makes encryption deterministic: the same input gives the same output. The price is flexibility.
If the same input recurs, all an observer learns is that two messages were identical, not the key or the plaintext. That is a far milder outcome than nonce reuse in GCM. GCM-SIV (RFC 8452, 2019) is the more modern sibling with better performance.