jdk.security.Signature — clojure-interop/java.security 1.0.4

The Signature class is used to provide applications the functionality of a digital signature algorithm. Digital signatures are used for authentication and integrity assurance of digital data.

The signature algorithm can be, among others, the NIST standard DSA, using DSA and SHA-256. The DSA algorithm using the SHA-256 message digest algorithm can be specified as SHA256withDSA. In the case of RSA the signing algorithm could be specified as, for example, SHA256withRSA. The algorithm name must be specified, as there is no default.

A Signature object can be used to generate and verify digital signatures.

There are three phases to the use of a Signature object for either signing data or verifying a signature:

Initialization, with either

a public key, which initializes the signature for
verification (see initVerify), or

a private key (and optionally a Secure Random Number Generator),
which initializes the signature for signing
(see initSign(PrivateKey)
and initSign(PrivateKey, SecureRandom)).

Updating

Depending on the type of initialization, this will update the bytes to be signed or verified. See the update methods.

Signing or Verifying a signature on all updated bytes. See the sign methods and the verify method.

Note that this class is abstract and extends from SignatureSpi for historical reasons. Application developers should only take notice of the methods defined in this Signature class; all the methods in the superclass are intended for cryptographic service providers who wish to supply their own implementations of digital signature algorithms.

Every implementation of the Java platform is required to support the following standard Signature algorithms:

SHA1withDSA SHA1withRSA SHA256withRSA

These algorithms are described in the Signature section of the Java Cryptography Architecture Standard Algorithm Name Documentation. Consult the release documentation for your implementation to see if any other algorithms are supported.

*get-instance clj

(*get-instance algorithm)

(*get-instance algorithm provider)

Returns a Signature object that implements the specified signature algorithm.

A new Signature object encapsulating the SignatureSpi implementation from the specified provider is returned. The specified provider must be registered in the security provider list.

Note that the list of registered providers may be retrieved via the Security.getProviders() method.

algorithm - the name of the algorithm requested. See the Signature section in the Java Cryptography Architecture Standard Algorithm Name Documentation for information about standard algorithm names. - java.lang.String provider - the name of the provider. - java.lang.String

returns: the new Signature object. - java.security.Signature

throws: java.security.NoSuchAlgorithmException - if a SignatureSpi implementation for the specified algorithm is not available from the specified provider.

clone clj

(clone this)

Returns a clone if the implementation is cloneable.

returns: a clone if the implementation is cloneable. - java.lang.Object

throws: java.lang.CloneNotSupportedException - if this is called on an implementation that does not support Cloneable.

get-algorithm clj

(get-algorithm this)

Returns the name of the algorithm for this signature object.

returns: the name of the algorithm for this signature object. - java.lang.String

get-parameter clj

(get-parameter this param)

Deprecated.

param - the string name of the parameter. - java.lang.String

returns: the object that represents the parameter value, or null if there is none. - java.lang.Object

throws: java.security.InvalidParameterException - if param is an invalid parameter for this engine, or another exception occurs while trying to get this parameter.

get-parameters clj

(get-parameters this)

Returns the parameters used with this signature object.

The returned parameters may be the same that were used to initialize this signature, or may contain a combination of default and randomly generated parameter values used by the underlying signature implementation if this signature requires algorithm parameters but was not initialized with any.

returns: the parameters used with this signature, or null if this signature does not use any parameters. - java.security.AlgorithmParameters

get-provider clj

(get-provider this)

Returns the provider of this signature object.

returns: the provider of this signature object - java.security.Provider

init-sign clj

(init-sign this private-key)

(init-sign this private-key random)

Initialize this object for signing. If this method is called again with a different argument, it negates the effect of this call.

private-key - the private key of the identity whose signature is going to be generated. - java.security.PrivateKey random - the source of randomness for this signature. - java.security.SecureRandom

throws: java.security.InvalidKeyException - if the key is invalid.

init-verify clj

(init-verify this public-key)

Initializes this object for verification. If this method is called again with a different argument, it negates the effect of this call.

public-key - the public key of the identity whose signature is going to be verified. - java.security.PublicKey

throws: java.security.InvalidKeyException - if the key is invalid.

set-parameter clj

(set-parameter this params)

(set-parameter this param value)

Deprecated. Use setParameter.

param - the string identifier of the parameter. - java.lang.String value - the parameter value. - java.lang.Object

throws: java.security.InvalidParameterException - if param is an invalid parameter for this signature algorithm engine, the parameter is already set and cannot be set again, a security exception occurs, and so on.

sign clj

(sign this)

(sign this outbuf offset len)

Finishes the signature operation and stores the resulting signature bytes in the provided buffer outbuf, starting at offset. The format of the signature depends on the underlying signature scheme.

This signature object is reset to its initial state (the state it was in after a call to one of the initSign methods) and can be reused to generate further signatures with the same private key.

outbuf - buffer for the signature result. - byte[] offset - offset into outbuf where the signature is stored. - int len - number of bytes within outbuf allotted for the signature. - int

returns: the number of bytes placed into outbuf. - int

throws: java.security.SignatureException - if this signature object is not initialized properly, if this signature algorithm is unable to process the input data provided, or if len is less than the actual signature length.

to-string clj

(to-string this)

Returns a string representation of this signature object, providing information that includes the state of the object and the name of the algorithm used.

returns: a string representation of this signature object. - java.lang.String

update clj

(update this b)

(update this data off len)

Updates the data to be signed or verified, using the specified array of bytes, starting at the specified offset.

data - the array of bytes. - byte[] off - the offset to start from in the array of bytes. - int len - the number of bytes to use, starting at offset. - int

throws: java.security.SignatureException - if this signature object is not initialized properly.

verify clj

(verify this signature)

(verify this signature offset length)

Verifies the passed-in signature in the specified array of bytes, starting at the specified offset.

A call to this method resets this signature object to the state it was in when previously initialized for verification via a call to initVerify(PublicKey). That is, the object is reset and available to verify another signature from the identity whose public key was specified in the call to initVerify.

signature - the signature bytes to be verified. - byte[] offset - the offset to start from in the array of bytes. - int length - the number of bytes to use, starting at offset. - int

returns: true if the signature was verified, false if not. - boolean

throws: java.security.SignatureException - if this signature object is not initialized properly, the passed-in signature is improperly encoded or of the wrong type, if this signature algorithm is unable to process the input data provided, etc.