A credential such as a One Time Password (OTP) can be proffered as a matrix of characters provided by a user. The verifier can accept that credential if it determines that the matrix is rank one. If it determines the matrix is not rank one, it can reject it or treat it as possibly corrupt due to one or more erroneous or missing entries. The verifier can factor the received matrix into two vectors and create a rank one projected matrix that is the product of the two vectors. The verifier can measure the distance between the received and projected matrices and accept the credential if the distance is within a distance threshold.