Number of bits in a key used by a cryptographic algorithm
In cryptography, key size or key length refers to the number of bits in a key used by a cryptographic algorithm (such as a cipher).
Key length defines the upper-bound on an algorithm's security (i.e. a logarithmic measure of the fastest known attack against an algorithm), because the security of all algorithms can be violated by brute-force attacks. Ideally, the lower-bound on an algorithm's security is by design equal to the key length (that is, the algorithm's design does not detract from the degree of security inherent in the key length).
Most symmetric-key algorithms are designed to have security equal to their key length. However, after design, a new attack might be discovered. For instance, Triple DES was designed to have a 168-bit key, but an attack of complexity 2112 is now known (i.e. Triple DES now only has 112 bits of security, and of the 168 bits in the key the attack has rendered 56 'ineffective' towards security). Nevertheless, as long as the security (understood as "the amount of effort it would take to gain access") is sufficient for a particular application, then it does not matter if key length and security coincide. This is important for asymmetric-key algorithms, because no such algorithm is known to satisfy this property; elliptic curve cryptography comes the closest with an effective security of roughly half its key length.
In cryptography, keysize or key length refers to the number of bits in a key used by a cryptographic algorithm (such as a cipher). Key length defines the...
different key and block sizes. For AES, NIST selected three members of the Rijndael family, each with a block size of 128 bits, but three different key lengths:...
are commonly sold in kits that include a variety of sizes. Key length typically increases with size but not necessarily proportionally so. Variants on...
Bra size (also known as brassiere measurement or bust size) indicates the size characteristics of a bra. While there is a number of bra sizing systems...
short 56-bit keysize. In January 1999, distributed.net and the Electronic Frontier Foundation collaborated to publicly break a DES key in 22 hours and...
USB HID protocol. A YubiKey can also present itself as an OpenPGP card using 1024, 2048, 3072 and 4096-bit RSA (for keysizes over 2048 bits, GnuPG version...
with typical keysizes. As a result, public-key cryptosystems are commonly hybrid cryptosystems, in which a fast high-quality symmetric-key encryption algorithm...
{\text{m}}} is the size of the string parameter key {\displaystyle {\text{key}}} , and d {\displaystyle {\text{d}}} corresponds to the alphabet size.: 754 Binary...
and 3DES encryption algorithms. This CVE, combined with the inadequate keysize of DES and 3DES, led to NIST deprecating DES and 3DES for new applications...
decryption, D. Both algorithms accept two inputs: an input block of size n bits and a key of size k bits; and both yield an n-bit output block. The decryption...
laptops due to their keyboard size restrictions. It is also found on many full-sized "multimedia" keyboards as the F-Lock key. It is mainly for the purpose...
4028237e+38 possibilities. The most likely option for cracking ciphers with high keysize is to find vulnerabilities in the cipher itself, like inherent biases and...
variable, including the block size and keysize, which are equal, as well as the number of rounds. In addition to the key, it also makes use of an odd...
key is commonly found on desktop and laptop keyboards. The key has the opposite effect of the End key. In limited-size keyboards where the Home key is...
offering 128 bits of security (256-bit keysize) and designed for use with the Elliptic-curve Diffie–Hellman (ECDH) key agreement scheme. It is one of the...
basslines. 49-key: considered the smallest MIDI keyboard size upon which to play two-handed piano parts effectively. 61-key: ideal size for playing two-handed...
the keysize. Once the restrictions were lifted, manufacturers of access points implemented an extended 128-bit WEP protocol using a 104-bit keysize (WEP-104)...
the cipher key called a round key. A key schedule is an algorithm that calculates all the round keys from the key. Some ciphers have simple key schedules...
and how similar the two keys are in size and shape. It can also refer to the measurable difference between a key and the size required to fit and operate...
(LUKS1) or 32 (LUKS2) encryption keys to be stored along with encryption parameters such as cipher type and keysize. The presence of this header is a...
AES-128 (keysize 128 bits) is designed to offer a 128-bit security level, which is considered roughly equivalent to a RSA using 3072-bit key. In this...
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