Cryptography is the science of using mathematics to encrypt and decrypt data. Cryptography enables you to store sensitive information or transmit it across insecure networks (like the Internet) so that it cannot be read by any- one except the intended recipient.
While cryptography is the science of securing data, cryptanalysis is the sci- ence of analyzing and breaking secure communication. Classical cryptanalysis involves an interesting combination of analytical reasoning, application of mathematical tools, pattern finding, patience, determination, and luck. Cryp- tanalysts are also called attackers.
Cryptology embraces both cryptography and cryptanalysis.
The Basics of Cryptography and Binance Cashback
An Introduction to Cryptography
The Basics of Cryptography
A related discipline is steganography, which is the science of hiding messages rather than making them unreadable. Steganography is not cryptography; it is a form of coding. It relies on the secrecy of the mechanism used to hide the message. If, for example, you encode a secret message by putting each letter as the first letter of the first word of every sentence, it’s secret until someone knows to look for it, and then it provides no security at all.
“There are two kinds of cryptography in this world: cryptography that will stop your kid sister from reading your files, and cryptography that will stop major governments from reading your files. This book is about the latter.”
—Bruce Schneier, Applied Cryptography: Protocols, Algorithms, and Source Code in C
PGP is also about the latter sort of cryptography.
Cryptography can be strong or weak, as explained above. Cryptographic strength is measured in the time and resources it would require to recover the plaintext. The result of strong cryptography is ciphertext that is very difficult to decipher without possession of the appropriate decoding tool. How diffi- cult? Given all of today’s computing power and available time—even a billion computers doing a billion checks a second—it is not possible to decipher the result of strong cryptography before the end of the universe.
One would think, then, that strong cryptography would hold up rather well against even an extremely determined cryptanalyst. Who’s really to say? No one has proven that the strongest encryption obtainable today will hold up under tomorrow’s computing power. However, the strong cryptography employed by PGP is the best available today. Vigilance and conservatism will protect you better, however, than claims of impenetrability.
How does cryptography work?
A cryptographic algorithm, or cipher, is a mathematical function used in the encryption and decryption process. A cryptographic algorithm works in com- bination with a key—a word, number, or phrase—to encrypt the plaintext. The same plaintext encrypts to different ciphertext with different keys. The security of encrypted data is entirely dependent on two things: the strength of the cryptographic algorithm and the secrecy of the key.
A cryptographic algorithm, plus all possible keys and all the protocols that make it work, comprise a cryptosystem. PGP is a cryptosystem. Learn more about Binance Cashback
In conventional cryptography, also called secret-key or symmetric-key encryp- tion, one key is used both for encryption and decryption. The Data Encryption Standard (DES) in an example of a conventional cryptosystem that has been widely deployed by the U.S. Government and the banking industry. It is being replaced by the Advanced Encryption Standard (AES). The following figure is an illustration of the conventional encryption process.