Php Defuse Crypto Generate Encryption Key

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Php Defuse Crypto Generate Encryption Key Generator
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The Crypto class provides encryption and decryption of strings either usinga secret key or secret password. For encryption and decryption of large files,see the File class.

I've dowloaded 'defuse/php-encryption' from GitHub. I tried the exemple founded here: How do you Encrypt and Decrypt a PHP String? But I didn't succeed. 'test.php' is in the same folder with 'Cr. Composer require defuse/php-encryption vendor/bin/generate-defuse-key. This will give a key that contains upper and lowercase letters and numbers and has sufficient entropy to be used for this simple operation. This key will need to be stored where PHP can access it but not someplace in (or even close to) the document root of the application. The all-in-one ultimate online toolbox that generates all kind of keys! Every coder needs All Keys Generator in its favorites! It is provided for free and only supported by ads and donations.

This code for this class is in src/Crypto.php.

Instance Methods

This class has no instance methods.

Apr 25, 2017 composer require defuse/php-encryption This is a library for encrypting data with a key or password in PHP. It requires PHP 5.6 or newer and OpenSSL 1.0.1 or newer. We recommend using a version of PHP that still has security support, which at the time of writing means PHP 7.1 or later. May 16, 2016 As part of our efforts to reduce the friction to adopt secure authenticated secret-key encryption in the PHP community, our Chief Development Officer has been helping Taylor Hornby develop the next version of Defuse Security's PHP Encryption Library (henceforth, referred to as. Data encryption in Teampass. Encryption is performed on passwords and custom fields. In other words the password strings stored by the users are encrypted in the database. All other fields are in clear text in the database. Encryption type. Encryption is performed using the Defuse PHP-Encryption library (Github project). Crypto at a Glance.

Static Methods

Crypto::encrypt($plaintext, Key $key, $raw_binary = false)

Description:

Encrypts a plaintext string using a secret key.

Parameters:

$plaintext is the string to encrypt.
$key is an instance of Key containing the secret key for encryption.
$raw_binary determines whether the output will be a byte string (true) orhex encoded (false, the default).

Return value:

Returns a ciphertext string representing $plaintext encrypted with the key$key. Knowledge of $key is required in order to decrypt the ciphertext andrecover the plaintext.

Exceptions:

DefuseCryptoExceptionEnvironmentIsBrokenException is thrown either whenthe platform the code is running on cannot safely perform encryption for somereason (e.g. it lacks a secure random number generator), or the runtime testsdetected a bug in this library.
TypeError is thrown if the parameters are not of the expected types.

Side-effects and performance:

This method runs a small and very fast set of self-tests if it is the very firsttime one of the Crypto methods has been called. The performance overhead isnegligible and can be safely ignored in all applications.

Cautions:

The ciphertext returned by this method is decryptable by anyone with knowledgeof the key $key. It is the caller's responsibility to keep $key secret.Where $key should be stored is up to the caller and depends on the threatmodel the caller is designing their application under. If you are unsure whereto store $key, consult with a professional cryptographer to get help designingyour application.

Please note that encryption does not, and is not intended to, hide thelength of the data being encrypted. For example, it is not safe to encrypta field in which only a small number of different-length values are possible(e.g. 'male' or 'female') since it would be possible to tell what the plaintextis by looking at the length of the ciphertext. In order to do this safely, it isyour responsibility to, before encrypting, pad the data out to the length of thelongest string that will ever be encrypted. This way, all plaintexts are thesame length, and no information about the plaintext can be gleaned from thelength of the ciphertext.

Crypto::decrypt($ciphertext, Key $key, $raw_binary = false)

Description:

Decrypts a ciphertext string using a secret key.

Parameters:

$ciphertext is the ciphertext to be decrypted.
$key is an instance of Key containing the secret key for decryption.
$raw_binary must have the same value as the $raw_binary given to thecall to encrypt() that generated $ciphertext.

Return value:

If the decryption succeeds, returns a string containing the same value as thestring that was passed to encrypt() when $ciphertext was produced. Upona successful return, the caller can be assured that $ciphertext could not havebeen produced except by someone with knowledge of $key.

Exceptions:

DefuseCryptoExceptionEnvironmentIsBrokenException is thrown either whenthe platform the code is running on cannot safely perform encryption for somereason (e.g. it lacks a secure random number generator), or the runtime testsdetected a bug in this library.
DefuseCryptoExceptionWrongKeyOrModifiedCiphertextException is thrown ifthe $key is not the correct key for the given ciphertext, or if theciphertext has been modified (possibly maliciously). There is no way todistinguish between these two cases.
TypeError is thrown if the parameters are not of the expected types.

Side-effects and performance:

Cautions:

It is impossible in principle to distinguish between the case where you attemptto decrypt with the wrong key and the case where you attempt to decrypta modified (corrupted) ciphertext. It is up to the caller how to best deal withthis ambiguity, as it depends on the application this library is being used in.If in doubt, consult with a professional cryptographer.

Crypto::encryptWithPassword($plaintext, $password, $raw_binary = false)

Description:

Encrypts a plaintext string using a secret password.

Parameters:

$plaintext is the string to encrypt.
$password is a string containing the secret password used for encryption.
$raw_binary determines whether the output will be a byte string (true) orhex encoded (false, the default).

Return value:

Returns a ciphertext string representing $plaintext encrypted with a keyderived from $password. Knowledge of $password is required in order todecrypt the ciphertext and recover the plaintext.

Exceptions:

DefuseCryptoExceptionEnvironmentIsBrokenException is thrown either whenthe platform the code is running on cannot safely perform encryption for somereason (e.g. it lacks a secure random number generator), or the runtime testsdetected a bug in this library.
TypeError is thrown if the parameters are not of the expected types.

Side-effects and performance:

This method is intentionally slow, using a lot of CPU resources for a fractionof a second. It applies key stretching to the password in order to make passwordguessing attacks more computationally expensive. If you need a faster way toencrypt multiple ciphertexts under the same password, see theKeyProtectedByPassword class.

Cautions:

PHP stack traces display (portions of) the arguments passed to methods on thecall stack. If an exception is thrown inside this call, and it is uncaught, thevalue of $password may be leaked out to an attacker through the stack trace.We recommend configuring PHP to never output stack traces (either displayingthem to the user or saving them to log files).

Crypto::decryptWithPassword($ciphertext, $password, $raw_binary = false)

Description:

Decrypts a ciphertext string using a secret password.

Parameters:

$ciphertext is the ciphertext to be decrypted.
$password is a string containing the secret password used for decryption.
$raw_binary must have the same value as the $raw_binary given to thecall to encryptWithPassword() that generated $ciphertext.

Return value:

If the decryption succeeds, returns a string containing the same value as thestring that was passed to encryptWithPassword() when $ciphertext wasproduced. Upon a successful return, the caller can be assured that $ciphertextcould not have been produced except by someone with knowledge of $password.

Exceptions:

DefuseCryptoExceptionEnvironmentIsBrokenException is thrown either whenthe platform the code is running on cannot safely perform encryption for somereason (e.g. it lacks a secure random number generator), or the runtime testsdetected a bug in this library.
DefuseCryptoExceptionWrongKeyOrModifiedCiphertextException is thrown ifthe $password is not the correct password for the given ciphertext, or ifthe ciphertext has been modified (possibly maliciously). There is no way todistinguish between these two cases.
TypeError is thrown if the parameters are not of the expected types.

Side-effects:

This method is intentionally slow. It applies key stretching to the password inorder to make password guessing attacks more computationally expensive. If youneed a faster way to encrypt multiple ciphertexts under the same password, seethe KeyProtectedByPassword class.

Cautions:

It is impossible in principle to distinguish between the case where you attemptto decrypt with the wrong password and the case where you attempt to decrypta modified (corrupted) ciphertext. It is up to the caller how to best deal withthis ambiguity, as it depends on the application this library is being used in.If in doubt, consult with a professional cryptographer.

Crypto::legacyDecrypt($ciphertext, $key)

Description:

Decrypts a ciphertext produced by version 1 of this library so that theplaintext can be re-encrypted into a version 2 ciphertext. See Upgrading fromv1.2.

Parameters:

$ciphertext is a ciphertext produced by version 1.x of this library.
$key is a 16-byte string (not a Key object) containing the key that wasused with version 1.x of this library to produce $ciphertext.

Return value:

If the decryption succeeds, returns the string that was encrypted to make$ciphertext by version 1.x of this library. Upon a successful return, thecaller can be assured that $ciphertext could not have been produced except bysomeone with knowledge of $key.

Exceptions:

DefuseCryptoExceptionEnvironmentIsBrokenException is thrown either whenthe platform the code is running on cannot safely perform encryption for somereason (e.g. it lacks a secure random number generator), or the runtime testsdetected a bug in this library.
DefuseCryptoExceptionWrongKeyOrModifiedCiphertextException is thrown ifthe $key is not the correct key for the given ciphertext, or if theciphertext has been modified (possibly maliciously). There is no way todistinguish between these two cases.
TypeError is thrown if the parameters are not of the expected types.

Side-effects:

Cautions:

PHP stack traces display (portions of) the arguments passed to methods on thecall stack. If an exception is thrown inside this call, and it is uncaught, thevalue of $key may be leaked out to an attacker through the stack trace. Werecommend configuring PHP to never output stack traces (either displaying themto the user or saving them to log files).

Hello! If you're reading this file, it's because you want to add encryption toone of your PHP projects. My job, as the person writing this documentation, isto help you make sure you're doing the right thing and then show you how to usethis library to do it. To help me help you, please read the documentationcarefully and deliberately.

A Word of Caution

Encryption is not magic dust you can sprinkle on a system to make it moresecure. The way encryption is integrated into a system's design needs to becarefully thought out. Sometimes, encryption is the wrong thing to use. Othertimes, encryption needs to be used in a very specific way in order for it towork as intended. Even if you are sure of what you are doing, we stronglyrecommend seeking advice from an expert.

The first step is to think about your application's threat model. Ask yourselfthe following questions. Who will want to attack my application, and what willthey get out of it? Are they trying to steal some information? Trying to alteror destroy some information? Or just trying to make the system go down so peoplecan't access it? Then ask yourself how encryption can help combat those threats.If you're going to add encryption to your application, you should have a veryclear idea of exactly which kinds of attacks it's helping to secure yourapplication against. Once you have your threat model, think about what kinds ofattacks it does not cover, and whether or not you should improve your threatmodel to include those attacks.

This isn't for storing user login passwords: The most common use ofcryptography in web applications is to protect the users' login passwords. Ifyou're trying to use this library to 'encrypt' your users' passwords, you're inthe wrong place. Passwords shouldn't be encrypted, they should be hashedwith a slow computation-heavy function that makes password guessing attacks moreexpensive. See How to Safely Store Your Users' Passwords in2016.

/key-tasks-for-generativity-vs-stagnation.html. This isn't for encrypting network communication: Likewise, if you're tryingto encrypt messages sent between two parties over the Internet, you don't wantto be using this library. For that, set up a TLS connection between the twopoints, or, if it's a chat app, use the SignalProtocol.

What this library provides is symmetric encryption for 'data at rest.' Thismeans it is not suitable for use in building protocols where 'data is in motion'(i.e. moving over a network) except in limited set of cases.

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Getting the Code

There are several different ways to obtain this library's code and to add it toyour project. Even if you've already cloned the code from GitHub, you shouldtake steps to verify the cryptographic signatures to make sure the code you gotwas not intercepted and modified by an attacker.

Please head over to the Installing andVerifying documentation to get the code, and thencome back here to continue the tutorial.

Using the Library

I'm going to assume you know what symmetric encryption is, and the differencebetween symmetric and asymmetric encryption. If you don't, I recommend takingDan Boneh's Cryptography I course onCoursera.

To give you a quick introduction to the library, I'm going to explain how itwould be used in two sterotypical scenarios. Hopefully, one of these sterotypesis close enough to what you want to do that you'll be able to figure out whatneeds to be different on your own.

Formal Documentation

While this tutorial should get you up and running fast, it's important tounderstand how this library behaves. Please make sure to read the formaldocumentation of all of the functions you're using, since there are someimportant security warnings there.

The following classes are available for you to use:

Crypto: Encrypting and decrypting strings.
File: Encrypting and decrypting files.
Key: Represents a secret encryption key.
KeyProtectedByPassword: Representsa secret encryption key that needs to be 'unlocked' by a password before itcan be used.

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Scenario #1: Keep data secret from the database administrator

In this scenario, our threat model is as follows. Alice is a serveradministrator responsible for managing a trusted web server. Eve is a databaseadministrator responsible for managing a database server. Dave is a webdeveloper working on code that will eventually run on the trusted web server.

Let's say Alice and Dave trust each other, and Alice is going to host Dave'sapplication on her server. But both Alice and Dave don't trust Eve. They knowEve is a good database administrator, but she might have incentive to steal thedata from the database. They want to keep some of the web application's datasecret from Eve.

In order to do that, Alice will use the included generate-defuse-key scriptwhich generates a random encryption key and prints it to standard output:

Alice will run this script once and save the output to a configuration file, sayin /etc/daveapp-secret-key.txt and set the file permissions so that only theuser that the website PHP scripts run as can access it.

Dave will write his code to load the key from the configuration file:

Then, whenever Dave wants to save a secret value to the database, he will firstencrypt it:

Whenever Dave wants to get the value back from the database, he must decrypt itusing the same key:

Note that if anyone ever steals the key from Alice's server, they can decryptall of the ciphertexts that are stored in the database. As part of our threatmodel, we are assuming Alice's server administration skills and Dave's securecoding skills are good enough to stop Eve from being able to steal the key.Under those assumptions, this solution will prevent Eve from seeing data that'sstored in the database.

However, notice that our threat model says nothing about what could happen ifEve wants to modify the data. With this solution, Eve will not be able toalter any individual ciphertext (because each ciphertext has its owncryptographic integrity check), but Eve will be able to swap ciphertexts forone another, and revert ciphertexts to what they used to be at previous times.If we needed to defend against such attacks, we would have to re-design ourthreat model and come up with a different solution.

Scenario #2: Encrypting account data with the user's login password

This scenario is like Scenario 1, but subtly different. The threat model is asfollows. We have Alice, a server administrator, and Dave, the developer. Aliceand Dave trust each other, and Alice wants to host Dave's web application,including its database, on her server. Alice is worried about her server gettinghacked. The application will store the users' credit card numbers, and Alicewants to protect them in case the server gets hacked.

We can model the situation like this: after the server gets hacked, the attackerwill have read and write access to all data on it until the attack is detectedand Alice rebuilds the server. We'll call the time the attacker has access tothe server the exposure window. One idea to minimize loss is to encrypt theusers' credit card numbers using a key made from their login password. Then, aslong as the users all have strong passwords, and they are never logged in duringthe exposure window, their credit cards will be protected from the attacker.

To implement this, Dave will use the KeyProtectedByPassword class. When a newuser account is created, Dave will save a new key to their account, one that'sprotected by their login password:

WARNING: Because of the way KeyProtectedByPassword is implemented, knowingSHA256($password) is enough to decrypt a KeyProtectedByPassword. To besecure, your application MUST NOT EVER compute SHA256($password) and use orstore it for any reason. You must also make sure that other libraries yourapplication is using don't compute it either.

Then, when the user logs in, Dave's code will load the protected key from theuser's account record, unlock it to get a Key object, and save the Keyobject somewhere safe (like temporary memory-backed session storage). Note thatwherever Dave's code saves the key, it must be destroyed once the user logs out,or else the attacker might be able to find users' keys even if they were neverlogged in during the attack.

When a user adds their credit card number, Dave's code will get the key from thesession and use it to encrypt the credit card number:

When the application needs to use the credit card number, it will decrypt it:

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With all caveats carefully heeded, this solution limits credit card numberexposure in the case where Alice's server gets hacked for a short amount oftime. Remember to think about the attacks that aren't included in our threatmodel. The attacker is still free to do all sorts of harmful things likemodifying the server's data which may go undetected if Alice doesn't have securebackups to compare against.

Getting Help

If you're having difficulty using the library, see if your problem is alreadysolved by an answer in the FAQ. Cygwin generating public ssh key.