A method includes determining a password-length threshold. The password-length threshold may comprise an integer. The method also includes obtaining, for a first user, a set of nucleotide locations. The number of nucleotide locations in the set may be greater than or equal to the integer. The method also includes obtaining a first sample of the user's DNA. The method also includes determining, in the first sample, a nucleotide at each nucleotide location in the set of nucleotide locations, resulting in a first nucleotide-password sequence. The method also includes performing a one-way hashing operation on the first nucleotide-password sequence with a first hashing algorithm, resulting in a first hashed password.