Final answer:
The Vigenere Cipher is a polyalphabetic substitution cipher that provides a higher level of security. However, it does not provide perfect secrecy and is vulnerable to certain attacks.
Step-by-step explanation:
The Vigenere Cipher, named after its inventor Blaise de Vigenere, is a polyalphabetic substitution cipher that is widely used in the field of cryptography. While it provides a higher level of security compared to simple substitution ciphers, it does not provide perfect secrecy.
The Vigenere Cipher operates by using a keyword to determine the shift of the alphabet for each letter. This enhances the security by making the ciphertext more difficult to crack using frequency analysis.
However, the Vigenere Cipher is still vulnerable to various attacks, such as the Kasiski examination and the Friedman test, which can help break the cipher and reveal the plaintext.