Java Pkcs 5 Passphrase Key Generation

This also applies to Java software keys automatically converted to PKCS#11 key objects when they are passed to the initialization method of a cryptographic operation, for example Signature.initSign., for keys created using either a generate or a create operation. Jan 24, 2017 Java provides classes for the generation of RSA public and private key pairs with the package java.security. You can use RSA keys pairs in public key cryptography. Public key cryptography uses a pair of keys for encryption. Distribute the public key to whoever needs it but safely secure the private key.

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In cryptography, PBKDF1 and PBKDF2 (Password-Based Key Derivation Function 2) are key derivation functions with a sliding computational cost, used to reduce vulnerabilities to brute force attacks.

PBKDF2 is part of RSA Laboratories' Public-Key Cryptography Standards (PKCS) series, specifically PKCS #5 v2.0, also published as Internet Engineering Task Force's RFC 2898. It supersedes PBKDF1, which could only produce derived keys up to 160 bits long.[1]RFC 8018 (PKCS #5 v2.1), published in 2017, recommends PBKDF2 for password hashing.[2]

Purpose and operation[edit]

PBKDF2 applies a pseudorandom function, such as hash-based message authentication code (HMAC), to the input password or passphrase along with a salt value and repeats the process many times to produce a derived key, which can then be used as a cryptographic key in subsequent operations. The added computational work makes password cracking much more difficult, and is known as key stretching.

When the standard was written in the year 2000 the recommended minimum number of iterations was 1000, but the parameter is intended to be increased over time as CPU speeds increase. A Kerberos standard in 2005 recommended 4096 iterations;[3] Apple reportedly used 2000 for iOS 3, and 10000 for iOS 4;[4] while LastPass in 2011 used 5000 iterations for JavaScript clients and 100000 iterations for server-side hashing.[5]

Algorithmic representation of the iterative process of the Password Based Key Derivation Function 2.

Having a salt added to the password reduces the ability to use precomputed hashes (rainbow tables) for attacks, and means that multiple passwords have to be tested individually, not all at once. The standard recommends a salt length of at least 64 bits.[6] The US National Institute of Standards and Technology recommends a salt length of 128 bits.[7]

Java pkcs 5 passphrase key generation 4

Key derivation process[edit]

The PBKDF2 key derivation function has five input parameters:[8] Generate rsa private key without passphrase.

where:

  • PRF is a pseudorandom function of two parameters with output length hLen (e.g., a keyed HMAC)
  • Password is the master password from which a derived key is generated
  • Salt is a sequence of bits, known as a cryptographic salt
  • c is the number of iterations desired
  • dkLen is the desired bit-length of the derived key
  • DK is the generated derived key

Each hLen-bit block Ti of derived key DK, is computed as follows (with + marking string concatenation):

The function F is the xor (^) of c iterations of chained PRFs. The first iteration of PRF uses Password as the PRF key and Salt concatenated with i encoded as a big-endian 32-bit integer as the input. (Note that i is a 1-based index.) Subsequent iterations of PRF use Password as the PRF key and the output of the previous PRF computation as the input:

where:

For example, WPA2 uses:

PBKDF1 had a simpler process: the initial U (called T in this version) is created by PRF(Password + Salt), and the following ones are simply PRF(Uprevious). The key is extracted as the first dkLen bits of the final hash, which is why there is a size limit.[8]

HMAC collisions[edit]

PBKDF2 has an interesting property when using HMAC as its pseudo-random function. It is possible to trivially construct any number of different password pairs with collisions within each pair.[9] If a supplied password is longer than the block size of the underlying HMAC hash function, the password is first pre-hashed into a digest, and that digest is instead used as the password. For example, the following password is too long:

  • Password:plnlrtfpijpuhqylxbgqiiyipieyxvfsavzgxbbcfusqkozwpngsyejqlmjsytrmd

therefore (when for example using HMAC-SHA1) it is pre-hashed using SHA-1 into:

  • SHA1 (hex): 65426b585154667542717027635463617226672a

Which can be represented in ASCII as:

  • SHA1 (ASCII): eBkXQTfuBqp'cTcar&g*

This means regardless of the salt or iterations, PBKDF2-HMAC-SHA1 will generate the same key bytes for the passwords:

  • 'plnlrtfpijpuhqylxbgqiiyipieyxvfsavzgxbbcfusqkozwpngsyejqlmjsytrmd'
  • 'eBkXQTfuBqp'cTcar&g*'

For example, using:

  • PRF: HMAC-SHA1
  • Salt: A009C1A485912C6AE630D3E744240B04
  • Iterations: 1,000
  • Derived key length: 16 bytes

the following two function calls:

Java Pkcs 5 Passphrase Key Generation 7

https://1985-Suzuki-Gs750-Service-Manual-Pdf-Free-Download.peatix.com/. will generate the same derived key bytes (17EB4014C8C461C300E9B61518B9A18B). These derived key collisions do not represent a security vulnerability – as one still must know the original password in order to generate the hash of the password.[10]

Alternatives to PBKDF2[edit]

One weakness of PBKDF2 is that while its number of iterations can be adjusted to make it take an arbitrarily large amount of computing time, it can be implemented with a small circuit and very little RAM, which makes brute-force attacks using application-specific integrated circuits or graphics processing units relatively cheap.[11] The bcrypt password hashing function requires a larger amount of RAM (but still not tunable separately, i. e. fixed for a given amount of CPU time) and is slightly stronger against such attacks,[12] while the more modern scrypt key derivation function can use arbitrarily large amounts of memory and is therefore more resistant to ASIC and GPU attacks.[11]

In 2013, a Password Hashing Competition (PHC) was held to develop a more resistant approach. On 20 July 2015 Argon2 was selected as the final PHC winner, with special recognition given to four other password hashing schemes: Catena, Lyra2, yescrypt and Makwa.[13]

See also[edit]

References[edit]

  1. ^<bkaliski@rsasecurity.com>, Burt Kaliski. 'PKCS #5: Password-Based Cryptography Specification Version 2.0'. tools.ietf.org. Retrieved 2015-10-23.
  2. ^'PKCS #5: Password-Based Cryptography Specification Version 2.1'. tools.ietf.org.
  3. ^Kenneth Raeburn. 'Advanced Encryption Standard (AES) Encryption for Kerberos 5'. tools.ietf.org. Retrieved 2015-10-23.
  4. ^'Smartphone Forensics: Cracking BlackBerry Backup Passwords'. Advanced Password Cracking – Insight (ElcomSoft). Retrieved 2015-10-23.
  5. ^'LastPass Security Notification'. The LastPass Blog. Retrieved 2015-10-23.
  6. ^K. Moriarty; et al. 'RFC 8018 - PKCS #5: Password-Based Cryptography Specification, Version 2.1'. tools.ietf.org. Retrieved 2018-01-24.
  7. ^Meltem Sönmez Turan, Elaine Barker, William Burr, and Lily Chen. 'NIST SP 800-132, Recommendation for Password-Based Key Derivation Part 1: Storage Applications'(PDF). www.nist.gov. Retrieved 2018-12-20.CS1 maint: multiple names: authors list (link)
  8. ^ abRFC2898
  9. ^https://mathiasbynens.be/notes/pbkdf2-hmac
  10. ^https://crypto.stackexchange.com/questions/26510/why-is-hmac-sha1-still-considered-secure
  11. ^ abColin Percival.scrypt.As presented in'Stronger Key Derivation via Sequential Memory-Hard Functions'.presented at BSDCan'09, May 2009.
  12. ^'New 25 GPU Monster Devours Passwords In Seconds'. The Security Ledger. 2012-12-04. Retrieved 2013-09-07.
  13. ^'Password Hashing Competition'

External links[edit]

  • RSA PKCS #5 – RSA Laboratories PKCS #5 v2.1.
  • RFC 2898 – Specification of PKCS #5 v2.0.
  • RFC 6070 – Test vectors for PBKDF2 with HMAC-SHA1.
Retrieved from 'https://en.wikipedia.org/w/index.php?title=PBKDF2&oldid=946120642'

(PHP 5 >= 5.2.2, PHP 7)

openssl_pkcs12_export — Exports a PKCS#12 Compatible Certificate Store File to variable

Description

openssl_pkcs12_export ( mixed$x509 , string&$out , mixed$priv_key , string$pass [, array$args ] ) : bool

openssl_pkcs12_export() stores x509 into a string named by out in a PKCS#12 file format.

Parameters

x509

See Key/Certificate parameters for a list of valid values.

out

/openssl-generate-aes-256-ctr-key.html. On success, this will hold the PKCS#12.

Java
priv_key

Private key component of PKCS#12 file. See Public/Private Key parameters for a list of valid values.

pass

Encryption password for unlocking the PKCS#12 file.

args
Optional array, other keys will be ignored.
KeyDescription
'extracerts'array of extra certificates or a single certificate to be included in the PKCS#12 file.
'friendlyname'string to be used for the supplied certificate and key

Return Values

Returns TRUE on success or FALSE on failure.

simoncpu was here
9 years ago
If your certificate is not password-protected, just use null or a blank string. Otherwise, this function won't work.
Robert
5 years ago
If you need to provide multiple additional certificates, the 'extracerts' argument needs to be an array with one certificate per element:
<?php
$args = array(
'extracerts' => array(
0 => '-----BEGIN CERTIFICATE----- cert1 .',
1 => '-----BEGIN CERTIFICATE----- cert2 .',
// .
)
);
?>

You can use this to prepare a PEM.
<?php
$pemChain = '.';
preg_match_all('/(-----BEGIN CERTIFICATE-----.*?-----END CERTIFICATE-----)/si', $pemChain, $matches);
$args = array('extracerts' => $matches[0]);
openssl_pkcs12_export($signed_csr, $cerificate_out, $private_key_resource, $passphrase, $args);
?>
Anonymous

Java Pkcs 5 Passphrase Key Generation Download

6 years ago
If you want to include CA-Certificates in the PKCS12 it can be accomplished by using the $args parameter.
<?php
$args = array(
'extracerts' => $CAcert,
'friendly_name' => 'My signed cert by CA certificate'
);
openssl_pkcs12_export($signed_csr, $cerificate_out, $private_key_resource, $passphrase, $args);
?>

Java Pkcs 5 Passphrase Key Generation 4

ismael at privasy dot org
5 years ago
in order to export a private key to pkcs12 format, the input certificate must contain both private and associated public key in PEM format ,
-----BEGIN RSA PRIVATE KEY-----
-----END RSA PRIVATE KEY-----
-----BEGIN CERTIFICATE-----
-----END CERTIFICATE-----
else this function might return the following error 'openssl_pkcs12_export(): cannot get cert from parameter 1'
mryom

Java Pkcs 5 Passphrase Key Generation Free

9 years ago
Example:
<?php
$key = openssl_pkey_get_private(Private_Key, Password);
openssl_pkcs12_export(Certificate, $iis, $key, Password);
?>

Java Pkcs 5 Passphrase Key Generation Free

  • OpenSSL Functions