# Using rainbow tables to find encryption keys of block ciphers?

Hi I have a question in mind.

Let's consider a block cipher whose key length is 36 bits. The bit-length of the plaintext is 256 bits, but there are only 16 possible plaintexts $m_0, m_1, . . . , m_{15}$. The encryptions are carried out in ECB mode and thus no IV is involved. We want to build a rainbow table such that, on input a ciphertext, we can readily find the key and the plaintexts.

How do we go about constructing a rainbow table for this purpose?