Triple-DES is still in use today but is widely considered a legacy encryption algorithm. DES is inherently insecure, while Triple-DES has much better security characteristics but is still considered problematic. NIST is the government organization that standardizes on cryptographic algorithms.
Block Cipher Principles. A stream cipher is one that encrypts a digital data stream one bit or one byte at a time. E.g, vigenere cipher. A block cipher is one in which a block of plaintext is treated as a whole and used to produce a cipher text block of equal length.
The S-DES decryption algorithm takes an 8-bit block of ciphertext and the same 10-bit key used to produce that ciphertext as input and produces the original 8-bit block of plaintext. The encryption algorithm involves five functions: an initial permutation (IP)
The DES algorithm uses the following steps:
- Step 1: Create 16 subkeys, each of which is 48-bits long. The 64-bit key is permuted according to the following table, PC-1.
- Step 2: Encode each 64-bit block of data. There is an initial permutation IP of the 64 bits of the message data M.
DES in hindi:-
DES ?? symmetric-key encryption ???? ?? ?????? message ?? encrypt ??? decrypt ???? ?? ??? ?? ?? key ?? ?????? ???? ???? ?? ?????? Sender ??? receiver ????? ?? ??? ???? private key ???? ??? ?? 56-bit key ?? ?????? ???? 64-bit data ?? encrypt ???? ??? DES ?? 1976 ??? IBM ?? develop ???? ???DES is Not Secure. DES, the Data Encryption Standard, can no longer be considered secure. While no major flaws in its innards are known, it is fundamentally inadequate because its 56-bit key is too short.
DES (Data Encryption Standard) and AES (Advanced Encryption Standard) both are the symmetric block cipher. The basic difference between DES and AES is that in DES plaintext block is divided into two halves before the main algorithm starts whereas, in AES the entire block is processed to obtain the ciphertext.
AES data encryption is a more mathematically efficient and elegant cryptographic algorithm, but its main strength rests in the option for various key lengths. AES allows you to choose a 128-bit, 192-bit or 256-bit key, making it exponentially stronger than the 56-bit key of DES.
DES is Not Secure. DES, the Data Encryption Standard, can no longer be considered secure. While no major flaws in its innards are known, it is fundamentally inadequate because its 56-bit key is too short. Of course this also applies to any other cipher with only a 56-bit key.
AES uses keys of 128, 192 or 256 bits, although, 128 bit keys provide sufficient strength today. It uses 128 bit blocks, and is efficient in both software and hardware implementations. 3DES is very slow especially in software implementations because DES was designed for performance in hardware.
DES has been linked to a variety of long-term adverse effects, such as increased risk of vaginal clear-cell adenocarcinoma, vaginal adenosis, T-shaped uterus, uterine fibroids, cervical weakness, breast cancer, infertility, hypogonadism, intersex defects, depression, and others, in women who were treated with it during
Doctors prescribed it from 1938 until 1971 to help some pregnant women who had had miscarriages or premature deliveries. Later, it was learned that infants whose mothers took DES during the first 5 months of pregnancy were more likely to have problems in their reproductive systems.
DES Daughters are defined as women born between 1938 and 1971 who were exposed to DES before birth (in the womb). Increased risk for clear cell cancer appears to be highest for DES Daughters in their teens and early 20s.
Part of what Triple DES does is to protect against brute force attacks. The original DES symmetric encryption algorithm specified the use of 56-bit keys -- not enough, by 1999, to protect against practical brute force attacks. Triple DES specifies the use of three distinct DES keys, for a total key length of 168 bits.
DES is linked to a rare cancer called clear cell adenocarcinoma (CCA) in a very small number of daughters of women who used DES during pregnancy. This cancer of the vagina and cervix usually occurs in DES-exposed daughters in their late teens or early 20s.
DES uses a single key for encryption and decryption; 3DES can use either two or three keys to make additional rounds of encryption. 3DES requires a fair amount of processing power to generate, but between the two it's the most secure.
Triple DES encryption process
It works by taking three 56-bit keys (K1, K2 and K3), and encrypting first with K1, decrypting next with K2 and encrypting a last time with K3. 3DES has two-key and three-key versions. In the two-key version, the same algorithm runs three times, but uses K1 for the first and last steps.In DES, encryption or decryption uses 16 × 2 + 2 = 34 permutations, because each mixer uses two permutations and there are two permutations before and after the rounds. The round-key generator uses 17 permutation operations: one parity drop and 16 compression permutation operations for each round.
RSA algorithm. RSA (Rivest–Shamir–Adleman) is an algorithm used by modern computers to encrypt and decrypt messages. It is an asymmetric cryptographic algorithm. Asymmetric means that there are two different keys. This is also called public key cryptography, because one of the keys can be given to anyone.
The Advanced Encryption Standard (AES) is a symmetric block cipher chosen by the U.S. government to protect classified information. AES is implemented in software and hardware throughout the world to encrypt sensitive data.
The uses of 3DES
It was one of the more commonly used encryption schemes before the rise of AES. Some examples of its implementations included Microsoft Office, Firefox and EMV payment systems. Many of these platforms no longer use 3DES because there are better alternatives.The DES algorithm uses a 56-bit key, and as expected from something with such a small key size, it is a symmetric key encryption algorithm—asymmetric keys are usually more than a thousand bits in length.
Double DES is a encryption technique which uses two instance of DES on same plain text. In both instances it uses different keys to encrypt the plain text. Both keys are required at the time of decryption.
The Data Encryption Standard (DES) is a symmetric key block cipher which takes 64-bit plaintext and 56-bit key as an input and produces 64-bit cipher text as output. Strength- The strength of DES lies on two facts: a. The use of 56-bit keys: 56-bit key is used in encryption, there are 256 possible keys.
DES is Not Secure. DES, the Data Encryption Standard, can no longer be considered secure. While no major flaws in its innards are known, it is fundamentally inadequate because its 56-bit key is too short. A group of well-known cryptographers looked at key lengths in a 1996 paper.
Advanced Encryption Standard, AES
There are three general classes of NIST-approved cryptographic algorithms, which are defined by the number or types of cryptographic keys that are used with each.
- Hash functions.
- Symmetric-key algorithms.
- Asymmetric-key algorithms.
- Hash Functions.
- Symmetric-Key Algorithms for Encryption and Decryption.
The DES function applies a 48-bit key to the rightmost 32 bits to produce a 32-bit output. XOR (Whitener). − After the expansion permutation, DES does XOR operation on the expanded right section and the round key. The round key is used only in this operation.
So for example, a 64-bit block cipher will take in 64 bits of plaintext and encrypt it into 64 bits of ciphertext. Majority of the symmetric ciphers used today are actually block ciphers. DES, Triple DES, AES, IDEA, and Blowfish are some of the commonly used encryption algorithms that fall under this group.
Originally adopted by the federal government, AES encryption has become the industry standard for data security. AES comes in 128-bit, 192-bit, and 256-bit implementations, with AES 256 being the most secure.
