Classical ciphers, such as Vigenère cipher, are weak and no longer be used. They can be broken by using frequency analysis, that is a well-known fact.
But, the frequency analysis often depends on the number of captured ciphertext, and/or the duplication of the text. What if the text was compressed by some types of algorithms (such as Huffman encoding，
lzma) before encrypting plaintext? For better security, assume there is no constant header, magic number, or any identifier in the plaintext.
How much difficulty was increased for frequency analysis attack?