What is AES?
Advanced Encryption Standard (AES) specifies a FIPS-approved cryptographic algorithm that can be used to protect electronic data. The AES algorithm is a symmetric block cipher that can encrypt (encipher) and decrypt (decipher) information. Encryption converts data to an unintelligible form called ciphertext; decrypting the ciphertext converts the data back into its original form, called plaintext. The AES algorithm is capable of using cryptographic keys of 128, 192, and 256 bits to encrypt and decrypt data in blocks of 128 bits.

History of AES:
Advanced Encryption Standard (AES) is an encryption standard adopted by the U.S. government. The standard comprises three block ciphers, AES-128, AES-192 and AES-256, adopted from a larger collection originally published as Rijndael. Each AES cipher has a 128-bit block size, with key sizes of 128, 192 and 256 bits, respectively. The AES ciphers have been analyzed extensively and are now used worldwide, as was the case with its predecessor, the Data Encryption Standard (DES).

Many Flash Drive manufactures are now selling compliant devices.  Most secure USB flash drives use some form of the Advanced Encryption Standard (AES) encryption, either 128-bit or 256-bit.  These levels are approved by the U.S. government for encrypting secret-level and top-secret-level documents and are HIPAA Compliant.  AES Security depends largely on the length and complexity of the password.  Most experts say a complex 16 to 20 character  password is required.