A cryptogram is a block of text which has been rendered unreadable through the use of what is called a “substitution cypher”. This means that each letter used in the original text has been substituted with another (G becomes A, F becomes P, etc.). Letter/word positions, spaces and punctuation remain unchanged. Cryptograms have been used...
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  In cryptography, a one-time pad is a system in which a private key generated randomly is used only once to encrypt a message that is then decrypted by the receiver using a matching one-time pad and key. Messages encrypted with keys based on randomness have the advantage that there is theoretically no way...
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Refers to a cryptography or security product that makes exaggerated claims of what the product is capable of, giving the user a false sense of security. The term snake oil, which is credited to Matt Curtin for using in reference to computer security products, comes from the 19th-century American practice of selling cure-all elixirs...
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algorithm A procedure or mathematical formula. Cryptographic algorithms convert plaintext to and from ciphertext. cipher Synonym for “cryptographic algorithm” cryptanalysis To solve or “break” a cryptosystem. EAR Export Administration Regulations. The rules under which the export of cryptographic software from the US are governed now. escrow A third party able to decrypt messages sent...
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Good cryptography is an excellent and necessary tool for almost anyone. Many good cryptographic products are available commercially, as shareware, or free. However, there are also extremely bad cryptographic products which not only fail to provide security, but also contribute to the many misconceptions and misunderstandings surrounding cryptography and security. Why “snake oil”? The term is used in many...
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The process of converting data into a coded form (ciphertext) to prevent it from being read and understood by an unauthorized party.  Encryption refers to algorithmic schemes that encode plain text into non-readable form or cyphertext, providing privacy. The receiver of the encrypted text uses a “key” to decrypt the message, returning it to its...
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Cryptanalysis is the art of deciphering encrypted communications without knowing the proper keys. Some of the more important cryptanalytic techniques are: Cipher text only attack: This is the situation where the attacker does not know anything about the contents of the message, and must work from cipher text only. In practice...
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A digital signature is a block of data that was created using a secret key, and for which a public key can be used to verify that the signature was generated using the corresponding private key. The algorithm used to generate the signature must be such that without knowing the secret key, it is...
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There are two classes of key-based algorithms, symmetric (or secret-key) and asymmetric (or public-key). The difference is that symmetric algorithms use the same key for encryption and decryption (or the decryption key is easily derived from the encryption key), whereas asymmetric algorithms use a different key for encryption and decryption, and the decryption key...
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Elliptic curve key pairs must be generated during the operation of each of the schemes specified in this document. The key pair generation process requires a secure random or pseudorandom number generator. Design of secure random and pseudorandom number generators is notoriously difficult and implementers should therefore take care to pay attention to this aspect of their...
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Elliptic curve points should be converted to octet strings as described in this section. Informally, if point compression is being used, the idea is that the compressed y-coordinate is placed in the leftmost octet of the octet string along with an indication that point compression is on, and the x-coordinate is placed in the remainder of the...
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The finite field F p is the prime finite field containing p elements. Although there is only one prime finite field F p for each odd prime p, there are many different ways to represent the elements of F p. Here the elements of F p should be represented by the set of integers: f0;1; : :...
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