org.jasypt.digest.config

## Interface DigesterConfig

- All Known Subinterfaces:
    StringDigesterConfig
  All Known Implementing Classes:
    EnvironmentDigesterConfig, EnvironmentStringDigesterConfig, SimpleDigesterConfig, SimpleStringDigesterConfig

      public interface DigesterConfig

  Common interface for config classes applicable to `StandardByteDigester`, `StandardStringDigester`, `PooledByteDigester` or `PooledStringDigester` objects.

  This interface lets the user create new `DigesterConfig` classes which retrieve values for this parameters from different (and maybe more secure) sources (remote servers, LDAP, other databases...), and do this transparently for the digester object.

  The config objects passed to a digester will only be queried once for each configuration parameter, and this will happen during the initialization of the digester object.

  For a default implementation, see `SimpleDigesterConfig`.

  Since:
    1.0
  Author:
    Daniel Fernández

- - ### Method Summary

    All Methods Instance Methods Abstract Methods
    Modifier and Type | Method and Description
    --- | ---
    `String` | `getAlgorithm()` Returns the name of an algorithm to be used for hashing, like "MD5" or "SHA-1".
    `Boolean` | `getInvertPositionOfPlainSaltInEncryptionResults()` Returns `Boolean.TRUE` if the plain (not hashed) salt bytes are to be appended after the digest operation result bytes.
    `Boolean` | `getInvertPositionOfSaltInMessageBeforeDigesting()` Returns `Boolean.TRUE` if the salt bytes are to be appended after the message ones before performing the digest operation on the whole.
    `Integer` | `getIterations()` Returns the number of times the hash function will be applied recursively.
    `Integer` | `getPoolSize()` Get the size of the pool of digesters to be created.
    `Provider` | `getProvider()` Returns the `java.security.Provider` implementation object to be used by the digester for obtaining the digest algorithm.
    `String` | `getProviderName()` Returns the name of the `java.security.Provider` implementation to be used by the digester for obtaining the digest algorithm.
    `SaltGenerator` | `getSaltGenerator()` Returns a `SaltGenerator` implementation to be used by the digester.
    `Integer` | `getSaltSizeBytes()` Returns the size of the salt to be used to compute the digest.
    `Boolean` | `getUseLenientSaltSizeCheck()` Returns `Boolean.TRUE` if digest matching operations will allow matching digests with a salt size different to the one configured in the "saltSizeBytes" property.

- - ### Method Detail

    - #### getAlgorithm

          String getAlgorithm()

      Returns the name of an algorithm to be used for hashing, like "MD5" or "SHA-1".

      This algorithm has to be supported by your Java Virtual Machine, and it should be allowed as an algorithm for creating java.security.MessageDigest instances.

      If this method returns null, the digester will ignore the config object when deciding the algorithm to be used.

      Returns:
        the name of the algorithm to be used, or null if this object will not want to set an algorithm. See Appendix A in the Java Cryptography Architecture API Specification & Reference for information about standard algorithm names.

    - #### getSaltSizeBytes

          Integer getSaltSizeBytes()

      Returns the size of the salt to be used to compute the digest. This mechanism is explained in PKCS #5: Password-Based Cryptography Standard.

      If salt size is set to zero, then no salt will be used.

      If this method returns null, the digester will ignore the config object when deciding the size of the salt to be used.

      Returns:
        the size of the salt to be used, in bytes, or null if this object will not want to set a size for salt.

    - #### getIterations

          Integer getIterations()

      Returns the number of times the hash function will be applied recursively.
      The hash function will be applied to its own results as many times as specified: h(h(...h(x)...))

      This mechanism is explained in PKCS #5: Password-Based Cryptography Standard.

      If this method returns null, the digester will ignore the config object when deciding the number of hashing iterations.

      Returns:
        the number of iterations, or null if this object will not want to set the number of iterations.

    - #### getSaltGenerator

          SaltGenerator getSaltGenerator()

      Returns a `SaltGenerator` implementation to be used by the digester.

      If this method returns null, the digester will ignore the config object when deciding the salt generator to be used.

      Returns:
        the salt generator, or null if this object will not want to set a specific SaltGenerator implementation.
      Since:
        1.2

    - #### getProviderName

          String getProviderName()

      Returns the name of the `java.security.Provider` implementation to be used by the digester for obtaining the digest algorithm. This provider must have been registered beforehand.

      If this method returns null, the digester will ignore this parameter when deciding the name of the security provider to be used.

      If this method does not return null, and neither does `getProvider()`, `providerName` will be ignored, and the provider object returned by `getProvider()` will be used.

      Returns:
        the name of the security provider to be used.
      Since:
        1.3

    - #### getProvider

          Provider getProvider()

      Returns the `java.security.Provider` implementation object to be used by the digester for obtaining the digest algorithm.

      If this method returns null, the digester will ignore this parameter when deciding the security provider object to be used.

      If this method does not return null, and neither does `getProviderName()`, `providerName` will be ignored, and the provider object returned by `getProvider()` will be used.

      The provider returned by this method does not need to be registered beforehand, and its use will not result in its being registered.

      Returns:
        the security provider object to be asked for the digest algorithm.
      Since:
        1.3

    - #### getInvertPositionOfSaltInMessageBeforeDigesting

          Boolean getInvertPositionOfSaltInMessageBeforeDigesting()

      Returns `Boolean.TRUE` if the salt bytes are to be appended after the message ones before performing the digest operation on the whole. The default behaviour is to insert those bytes before the message bytes, but setting this configuration item to `true` allows compatibility with some external systems and specifications (e.g. LDAP {SSHA}).

      Returns:
        whether salt will be appended after the message before applying the digest operation on the whole, instead of inserted before it (which is the default). If null is returned, the default behaviour will be applied.
      Since:
        1.7

    - #### getInvertPositionOfPlainSaltInEncryptionResults

          Boolean getInvertPositionOfPlainSaltInEncryptionResults()

      Returns `Boolean.TRUE` if the plain (not hashed) salt bytes are to be appended after the digest operation result bytes. The default behaviour is to insert them before the digest result, but setting this configuration item to `true` allows compatibility with some external systems and specifications (e.g. LDAP {SSHA}).

      Returns:
        whether plain salt will be appended after the digest operation result instead of inserted before it (which is the default). If null is returned, the default behaviour will be applied.
      Since:
        1.7

    - #### getUseLenientSaltSizeCheck

          Boolean getUseLenientSaltSizeCheck()

      Returns `Boolean.TRUE` if digest matching operations will allow matching digests with a salt size different to the one configured in the "saltSizeBytes" property. This is possible because digest algorithms will produce a fixed-size result, so the remaining bytes from the hashed input will be considered salt.

      This will allow the digester to match digests produced in environments which do not establish a fixed salt size as standard (for example, SSHA password encryption in LDAP systems).

      The value of this property will not affect the creation of digests, which will always have a salt of the size established by the "saltSizeBytes" property. It will only affect digest matching.

      Setting this property to `true` is not compatible with `SaltGenerator` implementations which return false for their `SaltGenerator.includePlainSaltInEncryptionResults()` property.

      Also, be aware that some algorithms or algorithm providers might not support knowing the size of the digests beforehand, which is also incompatible with a lenient behaviour.

      Default is `FALSE`.

      Returns:
        whether the digester will allow matching of digests with different salt sizes than established or not (default is false).
      Since:
        1.7

    - #### getPoolSize

          Integer getPoolSize()

      Get the size of the pool of digesters to be created.

      This parameter will be ignored if used with a non-pooled digester.

      Returns:
        the size of the pool to be used if this configuration is used with a pooled digester
      Since:
        1.7

Copyright © 2019 The JASYPT team. All rights reserved.