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A cryptographic key is a string of bits used by a cryptographic algorithm to transform plain text into cipher text or vice versa. This key remains private and ensures secure communication.
A cryptographic key is the core part of cryptographic operations. Many cryptographic systems include pairs of operations, such as encryption and decryption. A key is a part of the variable data that is provided as input to a cryptographic algorithm to execute this sort of operation. In a properly designed cryptographic scheme, the security of the scheme is dependent on the security of the keys used.
Cryptographic keys are symmetric or asymmetric. Symmetric encryption requires only one key, which is used to encrypt and decrypt data. Asymmetric encryption uses two different keys: one for encryption and one for decryption. A certificate authority (CA) provides public/private key pairs using the public key infrastructure. The digital certificate registration authority process begins before the user’s digital certificate status is communicated to the CA.
Cryptographic keys may be further indexed by the purposes for which they are used, which can include data encryption and decryption, digital signature verification, digital signature creation, message authentication, key transport and key wrapping.
The length of a key is normally expressed in bits. A longer key makes it more difficult to crack the encrypted data; however, a longer key results in longer time periods to perform encryption and decryption processes.
The CA provides the keys. The private key is given to the key requester. The public key is made public in an open access directory. Private keys never travel via the Internet and thus remain private.