The parameters consist of an effective key size and optionally * an 8-byte initialization vector (IV) (only in feedback mode). * *
This class can be used to initialize a Cipher object that
* implements the RC2 algorithm.
*
* @author Jan Luehe
*
* @since 1.4
*/
public class RC2ParameterSpec implements AlgorithmParameterSpec {
private byte[] iv = null;
private int effectiveKeyBits;
/**
* Constructs a parameter set for RC2 from the given effective key size
* (in bits).
*
* @param effectiveKeyBits the effective key size in bits.
*/
public RC2ParameterSpec(int effectiveKeyBits) {
this.effectiveKeyBits = effectiveKeyBits;
}
/**
* Constructs a parameter set for RC2 from the given effective key size
* (in bits) and an 8-byte IV.
*
*
The bytes that constitute the IV are those between
* iv[0] and iv[7] inclusive.
*
* @param effectiveKeyBits the effective key size in bits.
* @param iv the buffer with the 8-byte IV. The first 8 bytes of
* the buffer are copied to protect against subsequent modification.
* @exception IllegalArgumentException if iv is null.
*/
public RC2ParameterSpec(int effectiveKeyBits, byte[] iv) {
this(effectiveKeyBits, iv, 0);
}
/**
* Constructs a parameter set for RC2 from the given effective key size
* (in bits) and IV.
*
*
The IV is taken from iv, starting at
* offset inclusive.
* The bytes that constitute the IV are those between
* iv[offset] and iv[offset+7] inclusive.
*
* @param effectiveKeyBits the effective key size in bits.
* @param iv the buffer with the IV. The first 8 bytes
* of the buffer beginning at offset inclusive
* are copied to protect against subsequent modification.
* @param offset the offset in iv where the 8-byte IV
* starts.
* @exception IllegalArgumentException if iv is null.
*/
public RC2ParameterSpec(int effectiveKeyBits, byte[] iv, int offset) {
this.effectiveKeyBits = effectiveKeyBits;
if (iv == null) throw new IllegalArgumentException("IV missing");
int blockSize = 8;
if (iv.length - offset < blockSize) {
throw new IllegalArgumentException("IV too short");
}
this.iv = new byte[blockSize];
System.arraycopy(iv, offset, this.iv, 0, blockSize);
}
/**
* Returns the effective key size in bits.
*
* @return the effective key size in bits.
*/
public int getEffectiveKeyBits() {
return this.effectiveKeyBits;
}
/**
* Returns the IV or null if this parameter set does not contain an IV.
*
* @return the IV or null if this parameter set does not contain an IV.
* Returns a new array each time this method is called.
*/
public byte[] getIV() {
return (iv == null? null:(byte[])iv.clone());
}
/**
* Tests for equality between the specified object and this
* object. Two RC2ParameterSpec objects are considered equal if their
* effective key sizes and IVs are equal.
* (Two IV references are considered equal if both are null.)
*
* @param obj the object to test for equality with this object.
*
* @return true if the objects are considered equal, false if
* obj is null or otherwise.
*/
public boolean equals(Object obj) {
if (obj == this) {
return true;
}
if (!(obj instanceof RC2ParameterSpec)) {
return false;
}
RC2ParameterSpec other = (RC2ParameterSpec) obj;
return ((effectiveKeyBits == other.effectiveKeyBits) &&
java.util.Arrays.equals(iv, other.iv));
}
/**
* Calculates a hash code value for the object.
* Objects that are equal will also have the same hashcode.
*/
public int hashCode() {
int retval = 0;
if (iv != null) {
for (int i = 1; i < iv.length; i++) {
retval += iv[i] * i;
}
}
return (retval += effectiveKeyBits);
}
}