Java 的 public 密钥表示与 RFC 8410 之间存在差异

Question

RFC 8410 将此列为 Ed25519 public 密钥的示例：MCowBQYDK2VwAyEAGb9ECWmEzf6FQbrBZ9w7lshQhqowtrbLDFw4rXAxZuE=

用 ASN.1 解码器解码，变成：

30 2A
  30 05
    06 03 2B6570 // Algorithm Identifier
  03 21 0019BF44096984CDFE8541BAC167DC3B96C85086AA30B6B6CB0C5C38AD703166E1

正如预期的那样，这符合 RFC 中的 SubjectPublicKeyInfo 定义。

使用 Java 11+ 中的 Sun 加密提供程序我可以使用此代码生成 X25519（不是 Ed25519 - 这是下面算法标识符的区别）public 密钥：

import java.security.KeyPairGenerator;
import java.util.Base64;

public class PrintPublicKey {
    public static void main(String args[]) throws Exception {
        KeyPairGenerator generator = KeyPairGenerator.getInstance("X25519");
        byte[] encodedPublicKey = generator.generateKeyPair().getPublic().getEncoded();
        System.out.println(Base64.getEncoder().encodeToString(encodedPublicKey));
    }
}

这将输出如下内容：MCwwBwYDK2VuBQADIQDlXKI/cMoICnQRrV+4c//viHnXMoB190/z2MX/otJQQw==

用 ASN.1 解码器解码，变成：

30 2C
  30 07
    06 03 2B656E // Algorithm Identifier
    05 00        // Algorithm Parameters - NULL
  03 21 00E55CA23F70CA080A7411AD5FB873FFEF8879D7328075F74FF3D8C5FFA2D25043

这在对象标识符后有一个明确的 NULL。根据规范，这是否有效？它说：

In this document, we define four new OIDs for identifying the different curve/algorithm pairs: the curves being curve25519 and curve448 and the algorithms being ECDH and EdDSA in pure mode.

For all of the OIDs, the parameters MUST be absent.

Answer 1

你引用的那段之后的段落是这样说的：

It is possible to find systems that require the parameters to be present. This can be due to either a defect in the original 1997 syntax or a programming error where developers never got input where this was not true. The optimal solution is to fix these systems; where this is not possible, the problem needs to be restricted to that subsystem and not propagated to the Internet.

因此，对 Oracle 实施行为的一个合理解释是，他们希望与需要参数的旧系统进行互操作。这是您为防止拥有大量支持合同的大客户大声抱怨 "upgrading to Java 11 broke my infrastructure".

而做的事情

Java 的 public 密钥表示与 RFC 8410 之间存在差异

Discrepancy between Java's public key representation and RFC 8410

java

cryptography

public-key-encryption

x509

asn.1