Is there a cryptographic hash algorithm that, given the hash of a plaintext, supports supports efficient recomputation of the hash after modifying a single byte of the plaintext?
Specifically, is there a hash function H() such that, given plaintext P and Q of the same length that differ only in the byte at position K, there exists another function R() such that R(P, Q, K, H(P)) = H(Q) and R is O(1)? If so, what are H and R?
Such a function would be interesting because it would allow creating a filesystem that efficiently tracks a cryptographic hash for each of its files. Such a filesystem could be useful for implementing highly efficient file transfer (like rsync) or version control (like git) systems.