fix(keys): reject Ed25519 public keys that are not 32 bytes in publicKeyBytesToJwk

.changeset/ed25519-jwk-key-length.md

@@ -0,0 +1,9 @@
+---
+"@agentcommercekit/keys": patch
+---
+
+`publicKeyBytesToJwk` now rejects Ed25519 public keys that are not 32 bytes,
+as it already does for secp256k1 and secp256r1. The Ed25519 branch encoded
+whatever bytes it was given, so `createDidPkhDocument` built a DID document
+with a malformed `publicKeyJwk` for any Solana address that is valid base58
+but not a 32-byte key (for example `abc`) instead of failing.

packages/did/src/methods/did-pkh.test.ts

@@ -187,6 +187,15 @@ describe("createDidPkhDocument", () => {
     )
   })
 
+  it("throws for a Solana address that is not a 32-byte Ed25519 key", () => {
+    expect(() =>
+      createDidPkhDocument({
+        address: "abc",
+        chainId: "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
+      }),
+    ).toThrow("Invalid Ed25519 public key length")
+  })
+
   it("creates did:pkh document with custom controller", () => {
     const result = createDidPkhDocument({
       address: "0x1234567890123456789012345678901234567890",

packages/keys/src/encoding/jwk.test.ts

@@ -39,6 +39,15 @@ describe("JWK encoding", () => {
       expect(isBase64url(jwk.x)).toBe(true)
     })
 
+    test("throws for an Ed25519 public key that is not 32 bytes", () => {
+      expect(() => publicKeyBytesToJwk(new Uint8Array(2), "Ed25519")).toThrow(
+        "Invalid Ed25519 public key length",
+      )
+      expect(() => publicKeyBytesToJwk(new Uint8Array(33), "Ed25519")).toThrow(
+        "Invalid Ed25519 public key length",
+      )
+    })
+
     test("converts secp256k1 public key to JWK", () => {
       const jwk = publicKeyBytesToJwk(secp256k1Bytes, "secp256k1")
       if (!isPublicKeyJwkSecp256k1(jwk)) {

packages/keys/src/encoding/jwk.ts

@@ -229,6 +229,10 @@ export function publicKeyBytesToJwk(
 ): PublicKeyJwk {
   switch (curve) {
     case "Ed25519":
+      if (bytes.length !== 32) {
+        throw new Error(`Invalid ${curve} public key length`)
+      }
+
       return {
         kty: "OKP",
         crv: "Ed25519",