java.security.SignatureSpi Maven / Gradle / Ivy

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This work corresponds to the API signatures of JSR 219: Foundation Profile 1.1. In the event of a discrepency between this work and the JSR 219 specification, which is available at http://www.jcp.org/en/jsr/detail?id=219, the latter takes precedence. */ package java.security; import java.util.*; import java.io.*; import java.security.spec.AlgorithmParameterSpec; /** * This class defines the Service Provider Interface (SPI) * for the Signature class, which is used to provide the * functionality of a digital signature algorithm. Digital signatures are used * for authentication and integrity assurance of digital data. *. *

All the abstract methods in this class must be implemented by each * cryptographic service provider who wishes to supply the implementation * of a particular signature algorithm. * * @author Benjamin Renaud * * @version 1.15, 05/03/00 * * @see Signature */ public abstract class SignatureSpi { /** * Application-specified source of randomness. */ protected SecureRandom appRandom; public SignatureSpi() { } /** * Initializes this signature object with the specified * public key for verification operations. * * @param publicKey the public key of the identity whose signature is * going to be verified. * * @exception InvalidKeyException if the key is improperly * encoded, parameters are missing, and so on. */ protected abstract void engineInitVerify(PublicKey publicKey) throws InvalidKeyException; /** * Initializes this signature object with the specified * private key for signing operations. * * @param privateKey the private key of the identity whose signature * will be generated. * * @exception InvalidKeyException if the key is improperly * encoded, parameters are missing, and so on. */ protected abstract void engineInitSign(PrivateKey privateKey) throws InvalidKeyException; /** * Initializes this signature object with the specified * private key and source of randomness for signing operations. * *

This concrete method has been added to this previously-defined * abstract class. (For backwards compatibility, it cannot be abstract.) * * @param privateKey the private key of the identity whose signature * will be generated. * @param random the source of randomness * * @exception InvalidKeyException if the key is improperly * encoded, parameters are missing, and so on. */ protected void engineInitSign(PrivateKey privateKey, SecureRandom random) throws InvalidKeyException { } /** * Updates the data to be signed or verified * using the specified byte. * * @param b the byte to use for the update. * * @exception SignatureException if the engine is not initialized * properly. */ protected abstract void engineUpdate(byte b) throws SignatureException; /** * Updates the data to be signed or verified, using the * specified array of bytes, starting at the specified offset. * * @param b the array of bytes * @param off the offset to start from in the array of bytes * @param len the number of bytes to use, starting at offset * * @exception SignatureException if the engine is not initialized * properly */ protected abstract void engineUpdate(byte[] b, int off, int len) throws SignatureException; /** * Returns the signature bytes of all the data * updated so far. * The format of the signature depends on the underlying * signature scheme. * * @return the signature bytes of the signing operation's result. * * @exception SignatureException if the engine is not * initialized properly. */ protected abstract byte[] engineSign() throws SignatureException; /** * Finishes this 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. * *

The signature implementation is reset to its initial state * (the state it was in after a call to one of the * engineInitSign methods) * and can be reused to generate further signatures with the same private * key. * * This method should be abstract, but we leave it concrete for * binary compatibility. Knowledgeable providers should override this * method. * * @param outbuf buffer for the signature result. * * @param offset offset into outbuf where the signature is * stored. * * @param len number of bytes within outbuf allotted for the * signature. * Both this default implementation and the SUN provider do not * return partial digests. If the value of this parameter is less * than the actual signature length, this method will throw a * SignatureException. * This parameter is ignored if its value is greater than or equal to * the actual signature length. * * @return the number of bytes placed into outbuf * * @exception SignatureException if an error occurs or len * is less than the actual signature length. * * @since 1.2 */ protected int engineSign(byte[] outbuf, int offset, int len) throws SignatureException { return 0; } /** * Verifies the passed-in signature. * * @param sigBytes the signature bytes to be verified. * * @return true if the signature was verified, false if not. * * @exception SignatureException if the engine is not initialized * properly, or the passed-in signature is improperly encoded or * of the wrong type, etc. */ protected abstract boolean engineVerify(byte[] sigBytes) throws SignatureException; /** * Verifies the passed-in signature in the specified array * of bytes, starting at the specified offset. * *

Note: Subclasses should overwrite the default implementation. * * * @param sigBytes the signature bytes to be verified. * @param offset the offset to start from in the array of bytes. * @param length the number of bytes to use, starting at offset. * * @return true if the signature was verified, false if not. * * @exception SignatureException if the engine is not initialized * properly, or the passed-in signature is improperly encoded or * of the wrong type, etc. */ protected boolean engineVerify(byte[] sigBytes, int offset, int length) throws SignatureException { return false; } /** *

This method is overridden by providers to initialize * this signature engine with the specified parameter set. * * @param params the parameters * * @exception UnsupportedOperationException if this method is not * overridden by a provider * * @exception InvalidAlgorithmParameterException if this method is * overridden by a provider and the the given parameters * are inappropriate for this signature engine */ protected void engineSetParameter(AlgorithmParameterSpec params) throws InvalidAlgorithmParameterException { } /** *

This method is overridden by providers to return the * parameters used with this signature engine, or null * if this signature engine does not use any parameters. * *