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An Easy To Understand History Of Cryptography
History of encryption technology
An Easy To Understand History Of Cryptography
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Advanced Encryption Standard (AES), is the most prevalent symmetric encryption standard, utilized in hardware and software worldwide to safeguard sensitive information belonging to governments, corporations, and individuals. The roots of AES go back roughly 40 years. Aside from special coding used within the military, it was widely agreed that a trusted and certified standard for data encryption did not exist in the early 1970s. Thus the U.S. government and buyers needed reliable computer security to protect private documents and other sensitive information from digital intruders. A request was put forth by the National Institute of Technology and Standards (NIST) for a federal encryption standard that included among many criteria: a high level of security, easy to understand, available to all users, adaptable, and efficient. IBM stepped forward with a proposed algorithm which would become the basis for the Data Encryption Standard (DES). DES became a federal standard in 1977 and would soon be used worldwide. DES utilizes a 64 bit block size and key size of 56 bits (2^56 possibilities). During the 1970s, this key size was considered by most to be safe against brute-force attacks. A brute-force attack is the most basic method to crack a key and simply consists of trying every possible key. The main limitation to a brute-force attack is computing power. By the turn of the century, huge advancements in computer technology allowed for DES to be broken within a matter of days. Triple DES (3DES) was introduced in 1998, and essentially triples the key size to 168 bits by encrypting the data 3 times using the same DES algorithm. NIST (2007) projected 3DES to be safe for federal use until the year 2030 (p. 69). In addition to the diminishi...
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...very unwise to hide the key to these locks under the front door mat. Among many methods, random number generators are very useful for generating complex keys.
AES operates using a very high level process. Prior to the encryption process, the long input and cipher key are each broken up into 128-bit (16 byte) blocks and organized into two separate 4x4 matrices in the encryptor. The 4x4 input matrix, or the “State”, is sent to the encryption process (Figure 2) and the 4x4 cipher key matrix is sent to the key schedule. The State enters a process consisting of three phases. Each phase consists of rounds utilizing four types of transformations (Figure 3): “AddRoundKey”, “SubBytes”, “MixColumns”, and “ShiftRows”. Phase is one round of AddRoundKey. Phase two consists of 9, 11, or 13 repeated rounds (depending on the key size) of SubBytes, ShiftRows, MixColumns, and AddRound