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Creating and managing keys is an important part of the cryptographic process. Symmetric algorithms require the creation of a key and an initialization vector (IV). The key must be kept secret from anyone who should not decrypt your data. The IV does not have to be secret, but should be changed for each session. Asymmetric algorithms require the creation of a public key and a private key. The public key can be made public to anyone, while the private key must known only by the party who will decrypt the data encrypted with the public key. This section describes how to generate and manage keys for both symmetric and asymmetric algorithms.
Symmetric Keys
The symmetric encryption classes supplied by the .NET Framework require a key and a new initialization vector (IV) to encrypt and decrypt data. Whenever you create a new instance of one of the managed symmetric cryptographic classes using the parameterless constructor, a new key and IV are automatically created. Anyone that you allow to decrypt your data must possess the same key and IV and use the same algorithm. Generally, a new key and IV should be created for every session, and neither the key nor IV should be stored for use in a later session.
To communicate a symmetric key and IV to a remote party, you would usually encrypt the symmetric key by using asymmetric encryption. Sending the key across an insecure network without encrypting it is unsafe, because anyone who intercepts the key and IV can then decrypt your data. For more information about exchanging data by using encryption, see Creating a Cryptographic Scheme.
The following example shows the creation of a new instance of the TripleDESCryptoServiceProvider class that implements the TripleDES algorithm. Descargar key generator corel draw x7.
When the previous code is executed, a new key and IV are generated and placed in the Key and IV properties, respectively.
Sometimes you might need to generate multiple keys. In this situation, you can create a new instance of a class that implements a symmetric algorithm and then create a new key and IV by calling the GenerateKey and GenerateIV methods. The following code example illustrates how to create new keys and IVs after a new instance of the symmetric cryptographic class has been made.
When the previous code is executed, a key and IV are generated when the new instance of TripleDESCryptoServiceProvider is made. Another key and IV are created when the GenerateKey and GenerateIV methods are called.
Asymmetric Keys
The .NET Framework provides the RSACryptoServiceProvider and DSACryptoServiceProvider classes for asymmetric encryption. These classes create a public/private key pair when you use the parameterless constructor to create a new instance. Asymmetric keys can be either stored for use in multiple sessions or generated for one session only. While the public key can be made generally available, the private key should be closely guarded.
A public/private key pair is generated whenever a new instance of an asymmetric algorithm class is created. After a new instance of the class is created, the key information can be extracted using one of two methods:
Both methods accept a Boolean value that indicates whether to return only the public key information or to return both the public-key and the private-key information. An RSACryptoServiceProvider class can be initialized to the value of an RSAParameters structure by using the ImportParameters method.
Asymmetric private keys should never be stored verbatim or in plain text on the local computer. If you need to store a private key, you should use a key container. For more on how to store a private key in a key container, see How to: Store Asymmetric Keys in a Key Container.
The following code example creates a new instance of the RSACryptoServiceProvider class, creating a public/private key pair, and saves the public key information to an RSAParameters structure.
See also
RandPassGenerator 1.3The RandPassGenerator Java application is a simple command-line utility for generating random passwords, passphrases, and raw keys. It is designed very conservatively to ensure that the random values it provides offer full cryptographic strength requested by the user.
Usage Information
To use RandPassGenerator, you'll need the Oracle Java Runtime Environment; any recent version should be sufficient, but at a minimum version 9 is recommended.
The RandPassGenerator can also run from a terminal or console. The command-line syntax is simple:
![]() Options
-v {Print verbose messages during operation, in addition to logging}
-str S {Use generation strength of S bits (default: 160)}
-pw N {Generate N random password of the specified strength}
-pp N {Generate N random passphrases of the specified strength}
-k N {Generate N random keys of the specified strength}
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-enc {Encrypt generated random key using a random password that is at least a 16 characters (256-bit AES) and write to file named the Key ID (KEY_ID.enc). A prompt for a random password to us will appear. Users should generate a random password to use for encryption prior to generating keys. ('java -jar RandPassGenerator.jar -pw 1 -str 96' will generate a 16 character password).}
-decrypt {Decrypt encrypted key file using a random password that is at least a 16 characters and save as text file (KEY_ID_decrypted.txt). A prompt for the name of the encrypted file to decrypt will appear, then a prompt for the random password to use will appear.}
Unusual options:
-pplen M {When generating passphrases, longest word should be M letters long (minimum value of M is 3)}
-ppurl U {Use the URL U to load words for passphrase (default: use internal list)}
-pwcs P {Use character pattern P for characters to use in passwords (lowercase, uppercase, number, special character, or combination)}
-log F {Log all operations to the log file F (default: ./randpass.log)}
-out F {Write output to file F (default: writes to stdout)}
-c N {Format output passwords and keys in chunks of N characters}
-sep S {For chunk formatting, use S as the separator (default: -)}
At least one of the options -pw, -pp, or -k must be supplied. The keys, passwords, or passphrases produced by RandPassGenerator will be written to the standard output (stdout), so they can easily be redirected to a file. The -out option can also be used to write the output to a file. All messages are written to the standard error (stderr).
Detailed log messages are appended to the specified log file - if the log file cannot be opened, then the tool will not run.
Note that the -pwcs option is a little strange. Each character in the value represents a full set of characters. Any lowercase lettermeans 'add a character set of all lowercase letters', any uppercase letter means 'add a set of all uppercase letter', any digit means'add a set of all digits', and anything else means 'add a set of all punctuation marks'. There is no way to supply a fully custom character set. Normally, you should not use the -pwcs option, you should let RandPassGenerator use its default character set.
Examples
Example 1: generate 5 random passwords using the default mixed character set, at default strength of 160, saved into file GoodPasswords.dat
https://yeiwghz.weebly.com/blog/windows-7home-premium-product-key-generator. Example 2: generate 20 random passphrases using the default dictionary, at strength of 256, with verbose messages, using words up to 9 letters long, and output saved into the file passphrases.txt
Example 3: generate 200 random keys at strength of 192, with logging to keygen.log, and output to mykeys.out.
Example 4: generate 100 passwords at strength 160, using a character set of lowercase letters and digits, with output redirected to hi-quality-stuff.txt
Example 5: generate 10 passwords at strength 128, formatted into chunks of five characters each, separated by /.
Example 6: generate 1 random key at strength 256, and encrypt to file using random password.
Example 7: Decrypt encrypted key file.
Design Information![]()
The foundation of RandPassGenerator is an implementation of the NIST SP800-90 Hash DRBG. It uses entropy, carefully gathered from system sources, to generate quality random output. The internal strength of the DRBG is 192 bits, according to NIST SP800-57, using the SHA-384 algorithm. In accordance with SP800-90, the DRBG is seeded with at least 888 bits of high quality entropy from entropy sources prior to any operation.
This implementation uses the seed mechanism of the Java SecureRandom class for gathering entropy. This implementation performs self-tests at every execution, so that users can be confident that no library problems have affected operation. Two kinds of self-tests are performed:
If the tests don't pass, the tool reports failure and refuses to run.
The strength mechanism implemented here is quite simple. For passwords, the size of the character set used defines thebits-per-character, and password length is then computed to meet or exceed the requested strength (typically, this is somewhere around 5-6 bits per character). Similarly, for passphrases the size of the usable dictionary defines the bits-per-word, and passphrase length is then computed to meet or exceed the requested strength (for the default dictionary and settings, roughly 16 bits-per-word). Duplicates are eliminated and the entropy is computed based on the number of unique characters or words.
The RandPassGenerator tool performs extensive logging. By default, log entries are appended to the local file 'randpass.log'. No actual key data, random data, or seed data is written to the log file.
License
See LICENSE.
Java Random From Select NumbersContributing
See CONTRIBUTING.
DisclaimerJava Generate Random Number 1 10
See DISCLAIMER.
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