Class EMSA_PSS

public Object clone()

This method may be called to create a new copy of the Object. The typical behavior is as follows:

• o == o.clone() is false
• o.getClass() == o.clone().getClass() is true
• o.equals(o) is true

However, these are not strict requirements, and may be violated if necessary. Of the three requirements, the last is the most commonly violated, particularly if the subclass does not override Object.equals(Object).

If the Object you call clone() on does not implement Cloneable (which is a placeholder interface), then a CloneNotSupportedException is thrown. Notice that Object does not implement Cloneable; this method exists as a convenience for subclasses that do.

Object's implementation of clone allocates space for the new Object using the correct class, without calling any constructors, and then fills in all of the new field values with the old field values. Thus, it is a shallow copy. However, subclasses are permitted to make a deep copy.

All array types implement Cloneable, and override this method as follows (it should never fail):

 public Object clone()
 {
   try
     {
       super.clone();
     }
   catch (CloneNotSupportedException e)
     {
       throw new InternalError(e.getMessage());
     }
 }
 

Overrides:

clone in interface Object

Returns:

a copy of the Object

See Also:

Cloneable

public boolean decode(byte[] mHash,
                      byte[] EM,
                      int emBits,
                      int sLen)

The decoding operation EMSA-PSS-Decode recovers the message hash from an encoded message EM and compares it to the hash of M.

Parameters:

mHash - the byte sequence resulting from applying the message digest algorithm Hash to the message M.

EM - the encoded message, an octet string of length emLen = CEILING(emBits/8).

emBits - the maximal bit length of the integer OS2IP(EM), at least 8.hLen + 8.sLen + 9.

sLen - the length, in octets, of the expected salt.

Returns:

true if the result of the verification was consistent with the expected reseult; and false if the result was inconsistent.

Throws:

IllegalArgumentException - if an exception occurs.

public byte[] encode(byte[] mHash,
                     int emBits,
                     byte[] salt)

The encoding operation EMSA-PSS-Encode computes the hash of a message M using a hash function and maps the result to an encoded message EM of a specified length using a mask generation function.

Parameters:

mHash - the byte sequence resulting from applying the message digest algorithm Hash to the message M.

emBits - the maximal bit length of the integer OS2IP(EM), at least 8.hLen + 8.sLen + 9.

salt - the salt to use when encoding the output.

Returns:

the encoded message EM, an octet string of length emLen = CEILING(emBits / 8).

Throws:

IllegalArgumentException - if an exception occurs.

public static EMSA_PSS getInstance(String mdName)

Returns an instance of this object given a designated name of a hash function.

Parameters:

mdName - the canonical name of a hash function.

Returns:

an instance of this object configured for use with the designated options.