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 ...

The first table provides cryptoperiod for 19 types of key uses. A cryptoperiod is the time span during which a specific key is authorized for use by legitimate entities, or the keys for a given system will remain in effect. The second table presents the key length recommendations.

Sep 8, 2023 · The key length dictates the cryptographic strength, a longer key offering a sturdier defense against brute force attacks. Meanwhile, the choice of algorithm influences not just the security but also the speed of encryption and decryption processes.

Identify the cryptographic and key management requirements for your application and map all components that process or store cryptographic key material. Selection of the cryptographic and key management algorithms to use within a given application should begin with an understanding of the objectives of the application.

For symmetric cryptographic mechanisms, the key length, also known as key size, is the bit length of the secret key. For RSA (signature and encryption algorithms), the bit length of the RSA modulus n is referred to as key length.

Mar 14, 2019 · A simple, accessible recommendation for key sizes and recommended algorithms for various cryptographic algorithms.

Key sizes 1024 or less are associated with 80 bit security strength. Keys sizes 2048 or higher are associated with 112 bit security strength. For RSA keys, when functioning at GSK_FIPS_STATE_LEVEL2 or GSK_FIPS_STATE_LEVEL3, generating new keys and digital signatures are enforced at the 112 bit security strength.

For example, RSA using a key length of 1024 bits (i.e., 1024-bit RSA) has a security strength of 80 bits, as does 2-key Triple DES, while 2048-bit RSA and 3-key Triple DES have a security strength of 112 bits. See Table 2 in Part 1 of SP 800-57 for further security strength information.

Encryption strength is often described in terms of the size of the keys used to perform the encryption: in general, longer keys provide stronger encryption. Key length is measured in bits.

Symmetric algorithms use an identical key for both encryption and decryption. Asymmetric algorithms use different, mathematically related keys for encryption and decryption.