Search results
Results From The WOW.Com Content Network
Public-key cryptography, or asymmetric cryptography, is the field of cryptographic systems that use pairs of related keys. Each key pair consists of a public key and a corresponding private key. [1] [2] Key pairs are generated with cryptographic algorithms based on mathematical problems termed one-way functions.
Key agreement and key transport are the two types of a key exchange scheme that are used to be remotely exchanged between entities . In a key agreement scheme, a secret key, which is used between the sender and the receiver to encrypt and decrypt information, is set up to be sent indirectly.
E.g., an attacker who wants to know the decryption of a ciphertext c ≡ m e (mod n) may ask the holder of the private key d to decrypt an unsuspicious-looking ciphertext c′ ≡ cr e (mod n) for some value r chosen by the attacker. Because of the multiplicative property, c ' is the encryption of mr (mod n).
The length of the encryption key is an indicator of the strength of the encryption method. [28] For example, the original encryption key, DES (Data Encryption Standard), was 56 bits, meaning it had 2^56 combination possibilities. With today's computing power, a 56-bit key is no longer secure, being vulnerable to brute force attacks. [29]
Key exchange (also key establishment) is a method in cryptography by which cryptographic keys are exchanged between two parties, allowing use of a cryptographic algorithm. In the Diffie–Hellman key exchange scheme, each party generates a public/private key pair and distributes the public key. After obtaining an authentic copy of each other's ...
Symmetric-key cryptosystems use the same key for encryption and decryption of a message, although a message or group of messages can have a different key than others. A significant disadvantage of symmetric ciphers is the key management necessary to use them securely.
The resulting ciphertext will be impossible to decrypt or break if the following four conditions are met: [2] [3] The key must be at least as long as the plaintext. The key must be truly random. The key must never be reused in whole or in part. The key must be kept completely secret by the communicating parties.
Symmetric-key encryption: the same key is used for both encryption and decryption. Symmetric-key algorithms [a] are algorithms for cryptography that use the same cryptographic keys for both the encryption of plaintext and the decryption of ciphertext. The keys may be identical, or there may be a simple transformation to go between the two keys. [1]