A Vector Space Approach to Generate Dynamic Keys for Hill Cipher
This addresses a security problem in cryptography for applications requiring encryption, but it is incremental as it modifies an existing cipher.
The paper tackles the vulnerability of the classical Hill cipher to known-plaintext attacks by proposing a variant that encrypts each plaintext block with a new invertible key matrix, generated using vector spaces, random bases, and non-singular linear transformations, resulting in a cipher secure against such attacks.
In this paper, a variant of the Hill cipher is proposed. In the classical Hill cipher, an invertible matrix is used for encryption but the scheme is vulnerable to the known-plaintext attack which can reveal the matrix. In our proposed cryptosystem, each plaintext block is encrypted by a new invertible key matrix that thwarts the known-plaintext attack. To generate the invertible matrices which serve as the dynamic keys we make use of the vector spaces, randomly generated basis and non-singular linear transformation. Resulting cipher is secure against the known-plaintext attack.