An encryption key is nothing more than a number used to scramble (encrypt) data in such a way that it can later be unscrambled and restored to its original form. A common example of an encryption key is a password whose numeric representation may be used for this purpose. Encryption key pairs are two numbers that share a mathematical relationship such that data encrypted by one key of the pair can only be decrypted by the other key of that same pair.
A key in cryptography is a piece of information, usually a string of numbers or letters that are stored in a file, which, when processed through a cryptographic algorithm, can encode or decode cryptographic data. Based on the used method, the key can be different sizes and varieties, but in all cases, the strength of the encryption relies on the security of the key being maintained. A key’s security strength is dependent on its algorithm, the size of the key, the generation of the key, and the process of key exchange.