com.github.davidcarboni.cryptolite

Class DigitalSignature

java.lang.Object

com.github.davidcarboni.cryptolite.DigitalSignature

public class DigitalSignature
extends Object

This class provides a public-private key digital signature capability. The signature algorithm used is "SHA256withRSAandMGF1".

Author:

David Carboni

Field Summary

Fields

Modifier and Type	Field and Description
static String	ALGORITHM The digital signature algorithm to use: "SHA256withRSAandMGF1".

Constructor Summary

Constructors

Modifier	Constructor and Description
	DigitalSignature() The default constructor initialises the instance with the "SHA256withRSAandMGF1" algorithm.
protected	DigitalSignature(String algorithm) This constructor is protected so that, should you need a different algorithm (e.g.

Method Summary

Modifier and Type	Method and Description
protected Signature	getSignature()
String	sign(InputStream content, PrivateKey privateKey) Generates a digital signature for the given InputStream.
String	sign(String content, PrivateKey privateKey) Generates a digital signature for the given string.
boolean	verify(InputStream input, PublicKey publicKey, String signature)
boolean	verify(String content, PublicKey publicKey, String signature) Verifies whether the given content matches the given signature.

Methods inherited from class java.lang.Object

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

Field Detail

ALGORITHM

public static final String ALGORITHM

The digital signature algorithm to use: "SHA256withRSAandMGF1".

See Also:

Constant Field Values

Constructor Detail

DigitalSignature

public DigitalSignature()

The default constructor initialises the instance with the "SHA256withRSAandMGF1" algorithm.

DigitalSignature

protected DigitalSignature(String algorithm)

This constructor is protected so that, should you need a different algorithm (e.g. if you're integrating with a system that uses different crypto settings) it is possible to create a subclass with different settings.

Parameters:

algorithm - This should normally be "SHA256withRSAandMGF1".

Method Detail

sign

public String sign(String content,
                   PrivateKey privateKey)

Generates a digital signature for the given string.

Parameters:

content - The string to be digitally signed.

privateKey - The PrivateKey with which the string is to be signed. This can be obtained via Keys.newKeyPair().

Returns:

The signature as a base64-encoded string. If the content is null, null is returned.

sign

public String sign(InputStream content,
                   PrivateKey privateKey)

Generates a digital signature for the given InputStream.

Parameters:

content - The input to be digitally signed.

privateKey - The PrivateKey with which the input is to be signed. This can be obtained via Keys.newKeyPair().

Returns:

The signature as a base64-encoded string. If the content is null, null is returned.

verify

public boolean verify(String content,
                      PublicKey publicKey,
                      String signature)

Verifies whether the given content matches the given signature.

Parameters:

content - The content to be verified.

publicKey - The public key to use in the verification process.

signature - The signature with which the content is to be verified. This can be obtained via Keys.newKeyPair().

Returns:

If the content matches the given signature, using the given key, true.

verify

public boolean verify(InputStream input,
                      PublicKey publicKey,
                      String signature)

Parameters:

input - The content for which the signature is to be verified.

publicKey - The PublicKey corresponding to the PrivateKey that was used to sign the content. This can be obtained via Keys.newKeyPair().

signature - The signature to be verified.

Returns:

If the signature matches the input and key, true. Otherwise false.

getSignature

protected Signature getSignature()

Returns:

A new Signature instance.