org.apache.sshd.common.signature

Class AbstractSignature

java.lang.Object

org.apache.sshd.common.signature.AbstractSignature

All Implemented Interfaces:

AlgorithmNameProvider, Signature

Direct Known Subclasses:

SignatureDSA, SignatureECDSA, SignatureEd25519, SignatureRSA

public abstract class AbstractSignature
extends java.lang.Object
implements Signature

Useful base class for Signature implementation

Field Summary

Fields

Modifier and Type	Field and Description
private java.lang.String	algorithm
private java.security.Signature	signatureInstance

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractSignature(java.lang.String algorithm)

Method Summary

Modifier and Type	Method and Description
protected java.security.Signature	doInitSignature(SessionContext session, java.lang.String algo, java.security.Key key, boolean forSigning) Initializes the internal signature instance
protected boolean	doVerify(byte[] data)
protected java.util.Map.Entry<java.lang.String,byte[]>	extractEncodedSignature(byte[] sig, java.util.Collection<java.lang.String> expectedTypes) Makes an attempt to detect if the signature is encoded or pure data
protected java.util.Map.Entry<java.lang.String,byte[]>	extractEncodedSignature(byte[] sig, java.util.function.Predicate<? super java.lang.String> typeSelector)
java.lang.String	getAlgorithm()
protected java.security.Signature	getSignature()
void	initSigner(SessionContext session, java.security.PrivateKey key)
void	initVerifier(SessionContext session, java.security.PublicKey key)
byte[]	sign(SessionContext session) Compute the signature
java.lang.String	toString()
void	update(SessionContext session, byte[] hash, int off, int len) Update the computed signature with the given data

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.sshd.common.signature.Signature

update, verify

Field Detail

signatureInstance

private java.security.Signature signatureInstance

algorithm

private final java.lang.String algorithm

Constructor Detail

AbstractSignature

protected AbstractSignature(java.lang.String algorithm)

Method Detail

getAlgorithm

public final java.lang.String getAlgorithm()

Specified by:

getAlgorithm in interface AlgorithmNameProvider

doInitSignature

protected java.security.Signature doInitSignature(SessionContext session,
                                                  java.lang.String algo,
                                                  java.security.Key key,
                                                  boolean forSigning)
                                           throws java.security.GeneralSecurityException

Initializes the internal signature instance

Parameters:

session - The SessionContext for calling this method - may be null if not called within a session context

algo - The signature's algorithm name

key - the Key that is provided for initialization - a PrivateKey for signing and a PublicKey for verification

forSigning - If true then it is being initialized for signing, otherwise for verifying a signature

Returns:

The Signature instance

Throws:

java.security.GeneralSecurityException - if failed to initialize

getSignature

protected java.security.Signature getSignature()

Returns:

The current Signature instance - null if not initialized

See Also:

doInitSignature(SessionContext, String, Key, boolean)

sign

public byte[] sign(SessionContext session)
            throws java.lang.Exception

Description copied from interface: Signature

Compute the signature

Specified by:

sign in interface Signature

Parameters:

session - The SessionContext for calling this method - may be null if not called within a session context

Returns:

The signature value

Throws:

java.lang.Exception - If failed to calculate the signature

initVerifier

public void initVerifier(SessionContext session,
                         java.security.PublicKey key)
                  throws java.lang.Exception

Specified by:

initVerifier in interface Signature

Parameters:

session - The SessionContext for calling this method - may be null if not called within a session context

key - The PublicKey to be used for verifying signatures

Throws:

java.lang.Exception - If failed to initialize

initSigner

public void initSigner(SessionContext session,
                       java.security.PrivateKey key)
                throws java.lang.Exception

Specified by:

initSigner in interface Signature

Parameters:

session - The SessionContext for calling this method - may be null if not called within a session context

key - The PrivateKey to be used for signing

Throws:

java.lang.Exception - If failed to initialize

update

public void update(SessionContext session,
                   byte[] hash,
                   int off,
                   int len)
            throws java.lang.Exception

Description copied from interface: Signature

Update the computed signature with the given data

Specified by:

update in interface Signature

Parameters:

session - The SessionContext for calling this method - may be null if not called within a session context

hash - The hash data buffer

off - Offset of hash data in buffer

len - Length of hash data

Throws:

java.lang.Exception - If failed to update

extractEncodedSignature

protected java.util.Map.Entry<java.lang.String,byte[]> extractEncodedSignature(byte[] sig,
                                                                               java.util.Collection<java.lang.String> expectedTypes)

Makes an attempt to detect if the signature is encoded or pure data

Parameters:

sig - The original signature

expectedTypes - The expected encoded key types

Returns:

A AbstractMap.SimpleImmutableEntry where first value is the key type and second value is the data - null if not encoded

extractEncodedSignature

protected java.util.Map.Entry<java.lang.String,byte[]> extractEncodedSignature(byte[] sig,
                                                                               java.util.function.Predicate<? super java.lang.String> typeSelector)

doVerify

protected boolean doVerify(byte[] data)
                    throws java.security.SignatureException

Throws:

java.security.SignatureException

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object