A passphrase is a series of letters, characters, or words that can be combined to form a password. They are used by many computer programs to gain access to systems, data or messages. It is similar to the shorter passwords in use, but a passphrase can be up to 100 characters long and provide additional protection when needed. They can be used as a digital signature or to encrypt messages, and are often used by important systems that are vulnerable to outside hackers.
A passphrase works like a password.
While a password is usually 4-16 characters long, a password is usually at least 20-40. The common passphrase should only be known to the user, it should be long enough to remain difficult, hard to guess, easy to remember, and easy to type quickly and accurately. The passphrase should not be a common phrase or one from literature or culture. It should not be something with obvious meaning to the user or something that can be easily identified, even by people who know the user.
A passphrase can be difficult to remember, so make a note of it.
Different passphrases, just like different passwords, have different passphrase strengths. This is determined by the length of the sentence, the randomness of the sentence, and the use of characters available in the common lexicon. A phrase like “I AM THE KING OF THE WORLD” would not be good because it is not particularly original or unusual. Substitute numbers for vowels, or an anagram for a word, or a series of nonsense words, and the sentence becomes more difficult. “I4m7heK1ng0fTheW0r1d”, for example, would be much more difficult.
A passphrase can be easy or hard to remember and can be typed. Certain passphrases are made up of random groupings of numbers and letters, although a sense of structure makes them easier to remember. One method of formulating a long password is called Diceware. This tool consists of a list of 7776 short English words and is determined by rolling the dice. With a certain number of letters corresponding to each number on the die, different letter combinations form different words. These different words can be combined into a sentence with more than 2,000,000,000,000,000,000 possibilities.
The idea of the modern passphrase was invented by Sigmund N. Porter in 1982 as a means of additional protection when computer systems began to enter mainstream culture. Pretty Good Privacy, a popular passphrase method, revolutionized the practice in 1991. Created by Phil Zimmerman in the United States, it was used to encrypt emails and features a public and private passphrase encryption key. A private key is used to open and send messages in person, and another person’s public key is used to receive or send messages to that person.
The complexity of passwords can be more difficult for hackers to crack than traditional passwords.
