Abstract: | We present two new algorithms for decoding an arbitrary (n, k) linear rank distance code over GF(q
N
). These algorithms correct errors of rank r in O((Nr)3
q
(r–1)(k+1)) and O((k + r)3
r
3
q
(r–1)(N–r)) operations in GF(q) respectively. The algorithms give one of the most efficient attacks on public-key cryptosystems based on rank codes, as well as on the authentication scheme suggested by Chen. |