Password
Let us know how this article helped:. Learn how to update your Dropbox user name and profile picture. Dropbox Help center Sign-in help Password reset. How to reset your Dropbox password. Not receiving the password reset email? Check the spam folder of your inbox If the reset email isn't there, try adding no-reply dropbox. How to reset your password on dropbox. Click Forgot your password? Enter the email address you used to create the account. Check your email inbox and click the link in the email you received to reset your password. How to reset your password on the desktop app Click the Dropbox icon from the row of icons on your computer's desktop.
Click the globe icon, which will take you to dropbox. Click your avatar profile picture in the upper right corner. Select the Security tab. Many systems store a cryptographic hash of the password. If an attacker gets access to the file of hashed passwords guessing can be done offline, rapidly testing candidate passwords against the true password's hash value. In the example of a web-server, an online attacker can guess only at the rate at which the server will respond, while an off-line attacker who gains access to the file can guess at a rate limited only by the hardware on which the attack is running.
Passwords that are used to generate cryptographic keys e. Lists of common passwords are widely available and can make password attacks very efficient. Security in such situations depends on using passwords or passphrases of adequate complexity, making such an attack computationally infeasible for the attacker. An alternative to limiting the rate at which an attacker can make guesses on a password is to limit the total number of guesses that can be made. The password can be disabled, requiring a reset, after a small number of consecutive bad guesses say 5 ; and the user may be required to change the password after a larger cumulative number of bad guesses say 30 , to prevent an attacker from making an arbitrarily large number of bad guesses by interspersing them between good guesses made by the legitimate password owner.
Some computer systems store user passwords as plaintext , against which to compare user log on attempts. If an attacker gains access to such an internal password store, all passwords—and so all user accounts—will be compromised. If some users employ the same password for accounts on different systems, those will be compromised as well. 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. 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.
The main storage methods for passwords are plain text, hashed, hashed and salted, and reversibly encrypted. 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.
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. In particular, attackers can quickly recover passwords that are short, dictionary words, simple variations on dictionary words or that use easily guessable patterns. More recent Unix or Unix like systems e. See LM hash for a widely deployed, and insecure, example.
Passwords are vulnerable to interception i.
If the password is carried as electrical signals on unsecured physical wiring between the user access point and the central system controlling the password database, it is subject to snooping by wiretapping methods. If it is carried as packeted data over the Internet, anyone able to watch the packets containing the logon information can snoop with a very low probability of detection.
Email is sometimes used to distribute passwords but this is generally an insecure method. Since most email is sent as plaintext , a message containing a password is readable without effort during transport by any eavesdropper. Further, the message will be stored as plaintext on at least two computers: If it passes through intermediate systems during its travels, it will probably be stored on there as well, at least for some time, and may be copied to backup , cache or history files on any of these systems. Using client-side encryption will only protect transmission from the mail handling system server to the client machine.
Previous or subsequent relays of the email will not be protected and the email will probably be stored on multiple computers, certainly on the originating and receiving computers, most often in clear text. The risk of interception of passwords sent over the Internet can be reduced by, among other approaches, using cryptographic protection. There are several other techniques in use; see cryptography. Unfortunately, there is a conflict between stored hashed-passwords and hash-based challenge-response authentication ; the latter requires a client to prove to a server that they know what the shared secret i.
On many systems including Unix -type systems doing remote authentication, the shared secret usually becomes the hashed form and has the serious limitation of exposing passwords to offline guessing attacks. In addition, when the hash is used as a shared secret, an attacker does not need the original password to authenticate remotely; they only need the hash. Rather than transmitting a password, or transmitting the hash of the password, password-authenticated key agreement systems can perform a zero-knowledge password proof , which proves knowledge of the password without exposing it. Moving a step further, augmented systems for password-authenticated key agreement e.
An augmented system allows a client to prove knowledge of the password to a server, where the server knows only a not exactly hashed password, and where the unhashed password is required to gain access. Usually, a system must provide a way to change a password, either because a user believes the current password has been or might have been compromised, or as a precautionary measure.
If a new password is passed to the system in unencrypted form, security can be lost e. Some web sites include the user-selected password in an unencrypted confirmation e-mail message, with the obvious increased vulnerability. Identity management systems are increasingly used to automate issuance of replacements for lost passwords, a feature called self service password reset. The user's identity is verified by asking questions and comparing the answers to ones previously stored i. Some password reset questions ask for personal information that could be found on social media, such as mother's maiden name.
To request another email, follow the steps to recover your account. The main storage methods for passwords are plain text, hashed, hashed and salted, and reversibly encrypted. If a cryptographic hash function is well designed, it is computationally infeasible to reverse the function to recover a plaintext password. See LM hash for a widely deployed, and insecure, example. From Wikipedia, the free encyclopedia. Combining two or more unrelated words and altering some of the letters to special characters or numbers is another good method, [10] but a single dictionary word is not. Passwords are vulnerable to interception i.
As a result, some security experts recommend either making up one's own questions or giving false answers. Such policies usually provoke user protest and foot-dragging at best and hostility at worst. There is often an increase in the people who note down the password and leave it where it can easily be found, as well as helpdesk calls to reset a forgotten password. Users may use simpler passwords or develop variation patterns on a consistent theme to keep their passwords memorable. However, if someone may have had access to the password through some means, such as sharing a computer or breaching a different site, changing the password limits the window for abuse.
Allotting separate passwords to each user of a system is preferable to having a single password shared by legitimate users of the system, certainly from a security viewpoint. This is partly because users are more willing to tell another person who may not be authorized a shared password than one exclusively for their use. Separate logins are also often used for accountability, for example to know who changed a piece of data.
Common techniques used to improve the security of computer systems protected by a password include:. Some of the more stringent policy enforcement measures can pose a risk of alienating users, possibly decreasing security as a result. It is common practice amongst computer users to reuse the same password on multiple sites. This presents a substantial security risk, since an attacker need only compromise a single site in order to gain access to other sites the victim uses.
This problem is exacerbated by also reusing usernames , and by websites requiring email logins, as it makes it easier for an attacker to track a single user across multiple sites.
Reset your password
Password reuse can be avoided or minimused by using mnemonic techniques , writing passwords down on paper , or using a password manager. Historically, many security experts asked people to memorize their passwords: More recently, many security experts such as Bruce Schneier recommend that people use passwords that are too complicated to memorize, write them down on paper, and keep them in a wallet. Password manager software can also store passwords relatively safely, in an encrypted file sealed with a single master password.
A popular password manager software is 1Password. According to a survey by the University of London , one in ten people are now leaving their passwords in their wills to pass on this important information when they die. One third of people, according to the poll, agree that their password protected data is important enough to pass on in their will.
Two factor authentication makes passwords more secure. For example, two-factor authentication will send you a text message, e-mail, or alert via a third-party app whenever a login attempt is made and possibly ask you to verify a code sent to you.
Forgot Password?
Many websites put certain conditions on the passwords their users may choose. In a Wall Street Journal article, Burr reported he regrets these proposals and made a mistake when he recommended them. According to a 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. Combined with forced periodic password changes, this can lead to passwords that are difficult to remember but easy to crack. We are simply fooling the database that stores passwords into thinking the user did something good.
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.
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In a dictionary attack, all words in one or more dictionaries are tested. Lists of common passwords are also typically tested. Password strength is the likelihood that a password cannot be guessed or discovered, and varies with the attack algorithm used. Cryptologists and computer scientists often refer to the strength or 'hardness' in terms of entropy. Passwords easily discovered are termed weak or vulnerable ; passwords very difficult or impossible to discover are considered strong. There are several programs available for password attack or even auditing and recovery by systems personnel such as L0phtCrack , John the Ripper , and Cain ; some of which use password design vulnerabilities as found in the Microsoft LANManager system to increase efficiency.
These programs are sometimes used by system administrators to detect weak passwords proposed by users. Studies of production computer systems have consistently shown that a large fraction of all user-chosen passwords are readily guessed automatically. 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.
That "the password is dead" is a recurring idea in computer security. It often accompanies arguments that the replacement of passwords by a more secure means of authentication is both necessary and imminent.
This claim has been made by numerous people at least since Notably, Bill Gates , speaking at the RSA Conference predicted the demise of passwords saying "they just don't meet the challenge for anything you really want to secure. Now they are more than dead. The claim that "the password is dead" is often used by advocates of alternatives to passwords, such as biometrics , two-factor authentication or single sign-on.
Many initiatives have been launched with the explicit goal of eliminating passwords.