org.bouncycastle.gpg

Class KeyGripCalculator

java.lang.Object

org.bouncycastle.gpg.KeyGripCalculator

public class KeyGripCalculator
extends java.lang.Object

Compute the GnuPG-style "keygrip" for a public key. The keygrip is a 20-byte SHA-1 identifier used by GnuPG 2.x to look up a key without exposing the fingerprint, and is documented in agent/keyformat.txt of the GnuPG source tree.

The supplied PGPDigestCalculator must wrap SHA-1; the keygrip algorithm is fixed by the GnuPG specification.

Currently RSA public keys are supported; the algorithm matches libgcrypt's _gcry_rsa_compute_keygrip (SHA-1 of the canonical unsigned big-endian encoding of the modulus n).

Constructor Summary

Constructors

Constructor and Description
KeyGripCalculator(PGPDigestCalculator digestCalculator)

Method Summary

Modifier and Type	Method and Description
byte[]	calculateKeygrip(BCPGKey key) Compute the keygrip for the supplied PGP public-key material.

Methods inherited from class java.lang.Object

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

Constructor Detail

KeyGripCalculator

public KeyGripCalculator(PGPDigestCalculator digestCalculator)

Parameters:

digestCalculator - a SHA-1 digest calculator used to compute the keygrip.

Method Detail

calculateKeygrip

public byte[] calculateKeygrip(BCPGKey key)
                        throws java.io.IOException

Compute the keygrip for the supplied PGP public-key material.

Parameters:

key - the BCPGKey to be hashed.

Returns:

20 bytes of SHA-1 output.

Throws:

java.io.IOException - if writing to the digest calculator fails.

java.lang.IllegalArgumentException - if no keygrip algorithm is registered for the key type.