Provided are a method and an apparatus for generating and validating a digital signature. The apparatus for generating the digital signature includes: a converter converting a message to be transmitted into a codeword having a set length using a Griesmer code; and a digital signature generator allowing each of bits constituting the codeword to correspond to one of a plurality of secret keys constituting a table and combining the corresponding secret keys to generate the digital signature. The apparatus for validating the digital signature includes: a converter converting a received message into a codeword having a set length using a Griesmer code; and a digital signature validator allowing each of bits constituting the codeword to correspond to one of a plurality of public keys constituting a table and validating whether a value obtained by combining the corresponding public keys is equal to a value obtained by hashing the digital signature.