Describe frequency analysis 

Frequency analysis is a cryptographic technique used to break ciphers by analyzing the frequency of characters or patterns in the ciphertext. Key points include:

1. **Pattern Recognition:** Analyzes the frequency of letters or groups of letters to identify common patterns or repetitions in the encrypted text.

2. **Historical Use:** Effective against simple substitution ciphers, where each letter in the plaintext is replaced with another letter. The frequency distribution of letters in the ciphertext can reveal the encryption scheme.

3. **Application:** Helps in decrypting messages by comparing the frequency of characters in the ciphertext to known frequencies in the language of the plaintext.

4. **Limitations:** Less effective against more advanced encryption methods or ciphers that use complex substitutions and transpositions.

Frequency analysis exploits statistical properties of language to uncover hidden information in encrypted messages.