| A (transparent) specification of the key material
that constitutes a cryptographic key.
If the key is stored on a hardware device, its
specification may contain information that helps identify the key on the
device.
A key may be specified in an algorithm-specific way, or in an
algorithm-independent encoding format (such as ASN.1).
For example, a DSA private key may be specified by its components
x, p, q, and g
(see {@link DSAPrivateKeySpec}), or it may be
specified using its DER encoding
(see {@link PKCS8EncodedKeySpec}).
This interface contains no methods or constants. Its only purpose
is to group (and provide type safety for) all key specifications.
All key specifications must implement this interface. | 