Package se.swedenconnect.opensaml.xmlsec.encryption.support

Class RsaOaepMgf1Padding

java.lang.Object
se.swedenconnect.opensaml.xmlsec.encryption.support.RsaOaepMgf1Padding
public class RsaOaepMgf1Padding extends Object
Represents the RSA-OAEP-MGF1 padding mechanism for use in RSA encryption and decryption. This implementation provides padding and unpadding functionalities following the OAEP (Optimal Asymmetric Encryption Padding) scheme, using MGF1 as the mask generation function. The class ensures compatibility with the defined RSA key length and associated padding parameters.

RSA-OAEP is widely used for securely encrypting data with RSA. It combines the use of hash functions and MGF1 to provide semantic security against chosen plaintext attacks.

  • Constructor Summary

    Constructors
    Constructor
    Description
    RsaOaepMgf1Padding(OAEPParameterSpec parameterSpec, int rsaKeyLengthBits)
    Constructs an instance of the RsaOaepMgf1Padding class, initializing it with the provided OAEP parameter specification and RSA key length in bits.

  • Method Summary

    Modifier and Type
    Method
    Description
    byte[]
    pad(byte[] data)
    Pads the given data array using RSA-OAEP padding with a randomly generated seed.
    byte[]
    pad(byte[] data, byte[] seed)
    Pads the given data array using RSA-OAEP padding with the specified seed.
    byte[]
    unpad(byte[] padded)
    Removes the padding from the provided byte array, reversing the RSA-OAEP padding process.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • RsaOaepMgf1Padding

      public RsaOaepMgf1Padding(OAEPParameterSpec parameterSpec, int rsaKeyLengthBits) throws NoSuchAlgorithmException
      Constructs an instance of the RsaOaepMgf1Padding class, initializing it with the provided OAEP parameter specification and RSA key length in bits. It validates and configures the digest functions, computes essential parameters for padding operations, and ensures the RSA key length is suitable for RSA-OAEP padding.
      Parameters:
      parameterSpec - the OAEP parameter specification, which includes the digest algorithm, MGF parameters, and possibly more, providing configuration details for the padding
      rsaKeyLengthBits - the length of the RSA key, in bits. This should be a multiple of 8 and is used to calculate padding parameters and data constraints
      Throws:
      NoSuchAlgorithmException - if the specified digest algorithm in the provided parameter specification or the MGF parameters is not available
      IllegalArgumentException - if the MGF parameters are not of type MGF1ParameterSpec, or if rsaKeyLengthBits is not a multiple of 8

  • Method Details

    • pad

      public byte[] pad(byte[] data) throws BadPaddingException
      Pads the given data array using RSA-OAEP padding with a randomly generated seed.
      Parameters:
      data - the input data to be padded, which should not exceed the maximum allowable length based on the RSA modulus size and padding parameters
      Returns:
      a byte array containing the padded data
      Throws:
      BadPaddingException - if the input data length exceeds the allowable limit for padding or if the padding process encounters an error

    • pad

      public byte[] pad(byte[] data, byte[] seed) throws BadPaddingException
      Pads the given data array using RSA-OAEP padding with the specified seed.
      Parameters:
      data - the input data to be padded, which must not exceed the maximum allowable length based on the RSA modulus size and padding parameters
      seed - the seed value used for mask generation in the padding process
      Returns:
      a byte array containing the padded data
      Throws:
      BadPaddingException - if the input data length exceeds the allowable limit for padding or if the padding process encounters an error

    • unpad

      public byte[] unpad(byte[] padded) throws BadPaddingException
      Removes the padding from the provided byte array, reversing the RSA-OAEP padding process.
      Parameters:
      padded - the input byte array containing padded data. Its length must match the expected padded size, and it must conform to RSA-OAEP padding structure, including the specified padding and data encoding.
      Returns:
      a byte array containing the original unpadded data extracted from the padded input
      Throws:
      BadPaddingException - if the input does not conform to RSA-OAEP padding scheme, including errors like mismatched lengths, incorrect padding format, or hash validation failures