How to realize electronic signature in Java

Import? Java . security . invalidkeyexception；

Import? Java . security . key；

Import? Java . security . key pair；

Import? Java . security . key pair generator；

Import? Java . security . nosuchalgorithm exception；

Import? Java . security . private key；

Import? Java . security . public key；

Import? Java . security . securerandom；

Import? Java . security . signature；

Import? Java . security . signature exception；

Import? Java . util . logging . level；

Import? Java . util . logging . logger；

/**

*? ECDSA？ 160bit？ Signature and signature verification example

*/

Public? Class? ECDSASignature？ {

Public? Static electricity Invalid? Main (string? argv[])？ {

signatureTest()；

}

Public? Static electricity Invalid? signatureTest()？ {

/**

*? Key pair generation

*/

KeyPairGenerator？ keyPairGenerator？ =? null

Try it? {

keyPairGenerator？ =? keypairgenerator . getinstance(" EC ")；

}? Catch? (NoSuchAlgorithmException？ ex)？ {

Return;

}

SecureRandom？ secureRandom？ =? New? SecureRandom()；

keypairgenerator . initialize( 160，securer andom)；

KeyPair？ Pairing? =? keypairgenerator . generatekeypair()；

Keys? Public key? =? pair . get public()；

Keys? privateKey？ =? pair . get private()；

//? character string

String? hako？ =? "test";

/**

*? Private key signature (ECDSA? 160th bit)

*/

byte[]？ Sign? =? null

Try it? {

Signature? Sign your resignation? =? null

Sign your resignation? =? signature . getinstance(" NONEwithECDSA ")；

signature . init sign((private key)？ privateKey？ securer andom)；

signature . update(hako . getbytes())；

Sign? =? signature . sign()；

System.out.println("sign:"？ +? New? Character string (symbol));

}? Catch? (InvalidKeyException？ |? NoSuchAlgorithmException？ |? SignatureException？ ex)？ {

logger . get logger(ECD SAS signature . class . getname())。 Log (level. Is it serious? null，？ ex)；

}

/**

*? Signature verification with public key

*/

Signature? signatureVerify？ =? null

Try it? {

signatureVerify？ =? signature . getinstance(" NONEwithECDSA ")；

signatureverify . init verify((public key)？ public key)；

signatureverify . update(hako . getbytes())；

Bull? verifyResult？ =? SignatureVerify.verify (signature);

System. Out.println (verification result "signature OK"? :? "signature ng");

}? Catch? (NoSuchAlgorithmException？ |? InvalidKeyException？ |? SignatureException？ e)？ {

logger . get logger(ECD SAS signature . class . getname())。 Log (level. Is it serious? null，？ e)；

}

}

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