Exam 312-50v10 topic 1 question 152 discussion

(2) (Rivest-Shamir-Adleman) A highly secure cryptography method by RSA Security, Inc., Bedford, MA (www.rsa.com), a division of EMC Corporation since 2006. It uses a two-part key. The private key is kept by the owner; the public key is published. Data are encrypted by using the recipient's public key, which can only be decrypted by the recipient's private key. RSA is very computation intensive, thus it is often used to create a digital envelope, which holds an RSA-encrypted DES key and DES-encrypted data. This method encrypts the secret DES key so that it can be transmitted over the network, but encrypts and decrypts the actual message using the much faster DES algorithm.

ES is a symmetric algorithm which uses the same 128, 192, or 256 bit key for both encryption and decryption (the security of an AES system increases exponentially with key length). With even a 128-bit key, the task of cracking AES by checking each of the 2128 possible key values (a “brute force” attack) is so computationally intensive that even the fastest supercomputer would require