A password, sometimes called a passcode (for example in Apple devices),[1] is secret data, typically a string of characters, usually used to confirm a user's identity.[1] Traditionally, passwords were expected to be memorized,[2] but the large number of password-protected services that a typical individual accesses can make memorization of unique passwords for each service impractical.[3] Using the terminology of the NIST Digital Identity Guidelines,[4] the secret is held by a party called the claimant while the party verifying the identity of the claimant is called the verifier. When the claimant successfully demonstrates knowledge of the password to the verifier through an established authentication protocol,[5] the verifier is able to infer the claimant's identity.
In The Memorability and Security of Passwords,[16] Jeff Yan et al. examine the effect of advice given to users about a good choice of password. They found that passwords based on thinking of a phrase and taking the first letter of each word are just as memorable as naively selected passwords, and just as hard to crack as randomly generated passwords.
World War I full crack [Password]
Passwords that are used to generate cryptographic keys (e.g., for disk encryption or Wi-Fi security) can also be subjected to high rate guessing. Lists of common passwords are widely available and can make password attacks very efficient. (See Password cracking.) Security in such situations depends on using passwords or passphrases of adequate complexity, making such an attack computationally infeasible for the attacker. Some systems, such as PGP and Wi-Fi WPA, apply a computation-intensive hash to the password to slow such attacks. See key stretching.
More secure systems store each password in a cryptographically protected form, so access to the actual password will still be difficult for a snooper who gains internal access to the system, while validation of user access attempts remains possible. The most secure don't store passwords at all, but a one-way derivation, such as a polynomial, modulus, or an advanced hash function.[15] Roger Needham invented the now-common approach of storing only a "hashed" form of the plaintext password.[26][27] When a user types in a password on such a system, the password handling software runs through a cryptographic hash algorithm, and if the hash value generated from the user's entry matches the hash stored in the password database, the user is permitted access. The hash value is created by applying a cryptographic hash function to a string consisting of the submitted password and, in many implementations, another value known as a salt. A salt prevents attackers from easily building a list of hash values for common passwords and prevents password cracking efforts from scaling across all users.[28] MD5 and SHA1 are frequently used cryptographic hash functions, but they are not recommended for password hashing unless they are used as part of a larger construction such as in PBKDF2.[29]
The main storage methods for passwords are plain text, hashed, hashed and salted, and reversibly encrypted.[31] If an attacker gains access to the password file, then if it is stored as plain text, no cracking is necessary. If it is hashed but not salted then it is vulnerable to rainbow table attacks (which are more efficient than cracking). If it is reversibly encrypted then if the attacker gets the decryption key along with the file no cracking is necessary, while if he fails to get the key cracking is not possible. Thus, of the common storage formats for passwords only when passwords have been salted and hashed is cracking both necessary and possible.[31]
If a cryptographic hash function is well designed, it is computationally infeasible to reverse the function to recover a plaintext password. An attacker can, however, use widely available tools to attempt to guess the passwords. These tools work by hashing possible passwords and comparing the result of each guess to the actual password hashes. If the attacker finds a match, they know that their guess is the actual password for the associated user. Password cracking tools can operate by brute force (i.e. trying every possible combination of characters) or by hashing every word from a list; large lists of possible passwords in many languages are widely available on the Internet.[15] The existence of password cracking tools allows attackers to easily recover poorly chosen passwords. In particular, attackers can quickly recover passwords that are short, dictionary words, simple variations on dictionary words, or that use easily guessable patterns.[32]A modified version of the DES algorithm was used as the basis for the password hashing algorithm in early Unix systems.[33] The crypt algorithm used a 12-bit salt value so that each user's hash was unique and iterated the DES algorithm 25 times in order to make the hash function slower, both measures intended to frustrate automated guessing attacks.[33] The user's password was used as a key to encrypt a fixed value. More recent Unix or Unix-like systems (e.g., Linux or the various BSD systems) use more secure password hashing algorithms such as PBKDF2, bcrypt, and scrypt, which have large salts and an adjustable cost or number of iterations.[34]A poorly designed hash function can make attacks feasible even if a strong password is chosen. See LM hash for a widely deployed and insecure example.[35]
According to a 2017 rewrite of this NIST report, many websites have rules that actually have the opposite effect on the security of their users. This includes complex composition rules as well as forced password changes after certain periods of time. While these rules have long been widespread, they have also long been seen as annoying and ineffective by both users and cyber-security experts.[58] The NIST recommends people use longer phrases as passwords (and advises websites to raise the maximum password length) instead of hard-to-remember passwords with "illusory complexity" such as "pA55w+rd".[59] A user prevented from using the password "password" may simply choose "Password1" if required to include a number and uppercase letter. Combined with forced periodic password changes, this can lead to passwords that are difficult to remember but easy to crack.[56]
Pieris Tsokkis and Eliana Stavrou were able to identify some bad password construction strategies through their research and development of a password generator tool. They came up with eight categories of password construction strategies based on exposed password lists, password cracking tools, and online reports citing the most used passwords. These categories include user-related information, keyboard combinations and patterns, placement strategy, word processing, substitution, capitalization, append dates, and a combination of the previous categories[60]
Attempting to crack passwords by trying as many possibilities as time and money permit is a brute force attack. A related method, rather more efficient in most cases, is a dictionary attack. In a dictionary attack, all words in one or more dictionaries are tested. Lists of common passwords are also typically tested.
The numerous ways in which permanent or semi-permanent passwords can be compromised has prompted the development of other techniques. Unfortunately, some are inadequate in practice, and in any case few have become universally available for users seeking a more secure alternative.[70] A 2012 paper[71] examines why passwords have proved so hard to supplant (despite numerous predictions that they would soon be a thing of the past[72]); in examining thirty representative proposed replacements with respect to security, usability and deployability they conclude "none even retains the full set of benefits that legacy passwords already provide."
Many researchers have presented various ideas to curb the shoulder surfing attack. However, graphical passwords are still vulnerable to this attack. Therefore, in the present thesis, the solution for shoulder surfing attack is analyzed and a new algorithm is developed to provide better algorithm with memorability as well as very strong password using the encryption. For alphanumeric passwords, dictionary attack, and brute force attack are critical potential threats to be taken care off. Dictionary attacks mean, attacking every word from the dictionary to crack the password, whereas, brute force attack means, applying all different kind of combinations to crack the password. Thus, both protection methods have their pros and cons and, therefore in this thesis, the possible solution has been researched to provide more secure technique. Encryption is another essential technique in the field of cybersecurity. The history of encryption dates back to World War 2, where German forces used its encryption technique for the first time, and this encryption has been developed a lot with the consistent contribution of many researchers.
Would you carry around one key that fits your office, your home and your car doors? Of course not! If someone stole it they would be able to go everywhere you go and take all of your belongings with just the one key. Using the same password for different sites and services is very much the same. Typically website passwords can be reset by knowing and having access to the email account associated with it. In most cases the username is your email address, so with these bits of information an attacker could access all the sites you use such as Facebook, eBay, Pinterest, even your bank account! Changing the password from site to site keeps an attacker from using passwords acquired from cracking into a weak website and using that to access your accounts on other sites.
As an illustration: a seven character password in lower case letters could be one of over 8 billion possible permutations. The graphics processor on a typical computer graphics card (which are excellent for this task) can check over 150m words per second, meaning the maximum time to crack any password is a mere 53 seconds. 2ff7e9595c
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