The second argument indicates the desired bit length of the result, which must have a value of , , , , or 0 which is equivalent to Otherwise, the function result is a hash value containing the desired number of bits.
If the argument is not a compressed value, the result is NULL. Given an argument representing a plaintext password, this function returns an integer to indicate how strong the password is.
The return value ranges from 0 weak to strong. If that plugin is not installed, the function always returns 0. The password is subjected to increasingly strict tests and the return value reflects which tests were satisfied, as shown in the following table.
Built-In Function and Operator Reference. Loadable Function Reference. Type Conversion in Expression Evaluation. Comparison Functions and Operators.
Numeric Functions and Operators. Date and Time Functions. String Functions and Operators. String Comparison Functions and Operators. Character Set and Collation of Function Results. Natural Language Full-Text Searches. Full-Text Searches with Query Expansion. Encryption and Compression Functions. Spatial Analysis Functions. Spatial Function Reference.
Argument Handling by Spatial Functions. Geometry Format Conversion Functions. Geometry Property Functions. General Geometry Property Functions. Point Property Functions. Polygon and MultiPolygon Property Functions. GeometryCollection Property Functions. Spatial Operator Functions. Aggregate Functions. Aggregate Function Descriptions. Miscellaneous Functions. Types of Numeric Values. Expression Handling. Precision Math Examples. Most people still only use a couple of passwords for all their accounts, if one developer decides to use crappy encryption, or -heaven forbid- the developer leaks his key, all these accounts are at jeopardy.
I would even recommend you to encrypt and salt your passwords, just for extra safety; no worse publicity than 'website leaks xxxx passwords via security bug' — Erik Terwan. Terwanerik Thank you for changing my approach and know i came to know that its better to make someone's approach better rather than giving a solution to his bad approach. Or if you dont want to recover it you can change it via update command from mysql.
As noted by hd you could better use the generated string as reset token for your end-users. Sander Visser Sander Visser 3, 1 1 gold badge 27 27 silver badges 41 41 bronze badges. It should be noted that the generated random string that is e-mailed to the user should act as a "token" for them to log in to be directed to change their password straight away, and not to be used as their actual password, especially as you'd be sending a plain-text "password" via e-mail.
Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. The Overflow Blog. Stack Gives Back Safety in numbers: crowdsourcing data on nefarious IP addresses.
Featured on Meta. New post summary designs on greatest hits now, everywhere else eventually. This is a nonbinary string unless the character set is binary. Each pair of hexadecimal digits requires one byte in binary form, so the value of N depends on the length of the hex string. For SHA2 , N ranges from 28 to 32 depending on the argument specifying the desired bit length of the result. The size penalty for storing the hex string in a CHAR column is at least two times, up to eight times if the value is stored in a column that uses the utf8 character set where each character uses 4 bytes.
Storing the string also results in slower comparisons because of the larger values and the need to take character set collation rules into account. Applications should be prepared to handle the very rare case that a hashing function produces the same value for two different input values. One way to make collisions detectable is to make the hash column a primary key.
You may wish to consider using another one-way encryption function described in this section instead, such as SHA2. Passwords or other sensitive values supplied as arguments to encryption functions are sent as cleartext to the MySQL server unless an SSL connection is used. Also, such values appear in any MySQL logs to which they are written. To avoid these types of exposure, applications can encrypt sensitive values on the client side before sending them to the server.
The same considerations apply to encryption keys. To avoid exposing these, applications can use stored procedures to encrypt and decrypt values on the server side. By default these functions implement AES with a bit key length. Key lengths of or bits can be used, as described later. The key length is a trade off between performance and security. For example:. A passphrase can be used to generate an AES key by hashing the passphrase. Previous versions of this documentation suggested the former approach, but it is no longer recommended as the examples shown here are more secure.
Its default value is aesecb , which signifies encryption using a key length of bits and ECB mode. For a description of the permitted values of this variable, see Section 5. For encryption modes that require an initialization vector, the same vector must be used for encryption and decryption.
The following table lists each permitted block encryption mode and whether the initialization vector argument is required. For more information about that option, see Section 4. Compresses a string and returns the result as a binary string. This function requires MySQL to have been compiled with a compression library such as zlib. Otherwise, the return value is always NULL. Nonempty strings are stored as a 4-byte length of the uncompressed string low byte first , followed by the compressed string.
If the string ends with space, an extra. MD5 str. Calculates an MD5 bit checksum for the string. The return value can, for example, be used as a hash key.
See the notes at the beginning of this section about storing hash values efficiently.
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