如何使用FIPS BouncyCastle将ECPrivateKey转换为ECPublicKey？
如何使用FIPS BouncyCastle将ECPrivateKey转换为ECPublicKey？
提问于 2018-08-27 09:18:07
如何使用FIPS BouncyCastle将ECPrivateKey转换为ECPublicKey？
我使用以下代码(稍微简化)将ECPrivateKey转换为ECPublicKey：
public static ECPublicKey getPublicKeyFromPrivateKey(ECPrivateKey privateKey) throws GeneralSecurityException {
final KeyFactory keyFactory = KeyFactory.getInstance("ECDSA", new BouncyCastleProvider());
final BCECPrivateKey bcecPrivateKey = (BCECPrivateKey) privateKey;
final ECParameterSpec ecSpec = bcecPrivateKey.getParameters();
final ECPoint q = ecSpec.getG().multiply(bcecPrivateKey.getD());
final byte[] qBytes = q.getEncoded(false);
final ECPoint point = ecSpec.getCurve().decodePoint(qBytes);
final ECPublicKeySpec pubSpec = new ECPublicKeySpec(point, ecSpec);
return (ECPublicKey) keyFactory.generatePublic(pubSpec);
}这与非FIPS BouncyCastle一起工作得很好。现在，我们需要以符合FIPS的方式做同样的事情。这里的问题是，在FIPS BouncyCastle 1.0.1中似乎不存在像ECParameterSpec这样的类。我们如何使用FIPS BouncyCastle做同样的事情？
回答 1
Stack Overflow用户
回答已采纳
发布于 2020-03-24 06:48:40
我找到了以下对我有效的解决方案：
public static PublicKey getPublicKeyForPrivateKeyEC(ECPrivateKey privateKey) throws GeneralSecurityException {
final KeyFactory keyFactory = KeyFactory.getInstance("ECDSA", new BouncyCastleProvider());
final ECParameterSpec ecSpec = privateKey.getParams();
final ECCurve ecCurve = FipsECUtil.convertCurve(ecSpec);
final ECMultiplier multiplier = ecCurve.getMultiplier();
final ECPoint generatorP = FipsECUtil.convertPoint(ecSpec, ecSpec.getGenerator());
final ECPoint q = multiplier.multiply(generatorP, privateKey.getS());
final byte[] publicDerBytes = q.getEncoded(false);
final ECPoint point = ecCurve.decodePoint(publicDerBytes);
final ECPublicKeySpec pubSpec = new ECPublicKeySpec(new java.security.spec.ECPoint(
point.getAffineXCoord().toBigInteger(),
point.getAffineYCoord().toBigInteger()), ecSpec);
return keyFactory.generatePublic(pubSpec);
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/52031491
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