ECC私钥比公钥长

Question

我使用secp192r1曲线生成了ECC公钥和私钥。我得到75为公共和125为私人编码键长度。为什么私钥比公钥长？为什么私钥不比公众长两倍？为什么私钥不是192位= 24字节，因为secp192r1？

Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());

ECNamedCurveParameterSpec ecSpec = ECNamedCurveTable.getParameterSpec("secp192r1");

KeyPairGenerator g = KeyPairGenerator.getInstance("ECDSA", "BC");
g.initialize(ecSpec, new SecureRandom());
KeyPair pair = g.generateKeyPair();

System.out.println(pair.getPublic().getEncoded().length);
System.out.println(pair.getPrivate().getEncoded().length);

Answer 1

下面的代码片段输出24个字节的私钥：

Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());

ECNamedCurveParameterSpec spec = ECNamedCurveTable.getParameterSpec("secp192r1");

KeyPairGenerator g = KeyPairGenerator.getInstance("ECDSA", "BC");
g.initialize(spec, new SecureRandom());
KeyPair pair = g.generateKeyPair();
ECPrivateKey ecPrivateKey = (ECPrivateKey)pair.getPrivate();

System.out.println(ecPrivateKey.getS().toByteArray().length);