Suppose that two nodes are using a column based transposition cipher where number of columns is 4. The following plaintext becomes what ciphertext if key used is [3, 0, 2, 1]: I AM AT METRO

The Columnar Transposition Cipher is a form of transposition cipher just like Rail Fence Cipher. Columnar Transposition involves writing the plaintext out in rows, and then reading the ciphertext off in columns one by one.

CipherText for the given plaintext using the given key is as follows-

_AE_M_R_ATT_I_MO {_ represents a space}

Please see the attached file for the complete solution