Give JWK independent value semantics for thread-safe copies

CHANGELOG.md

@@ -0,0 +1,21 @@
+# Changelog
+
+## 0.5.0 - 2026-09-29
+
+### Added
+
+- Parsed `JWK` and `JwkSet` values now own their key material and metadata
+  allowing copies can be safely passed to worker threads without sharing
+  mutable JSON state.
+- Added `%jwk` serialization, which produces an independent `JsonNode` and
+  retains extension members.
+- The unit-test task now runs under threaded ARC and ORC memory management, with
+  coverage for copied key caches used concurrently by workers.
+
+### Changed
+
+- `initJwk` now snapshots its input JSON. Mutating the source `JsonNode` after
+  parsing no longer changes the resulting key.
+- `jwk["member"]` still returns `Option[JsonNode]`, but the node is now a fresh
+  copy. Mutating it no longer changes the key; construct a new key with
+  `initJwk` to make a modification.

README.md

@@ -4,6 +4,30 @@ This is a standards-compliant implementation of the JWT, JWK, JWS, and JWE
 standards in Nim, using the [BearSSL](https://www.bearssl.org/) library to
 provide the underlying cryptographic primatives.
 
+## JWK ownership and threads
+
+`JWK` and `JwkSet` have value semantics. Parsed keys own their key material and
+metadata; changing the input `JsonNode` after `initJwk` or `initJwkSet` does not
+change the keys. Assigning a key, key set, or `Table[string, JwkSet]` produces an
+independent value suitable for handing to a worker thread. Synchronize access
+to any source value that another thread may be modifying.
+
+The typed accessors (`kid`, `alg`, `rsaPrv`, etc.) return values. The JSON member
+accessor, `key["member"]`, keeps its `Option[JsonNode]` return type, but each call
+returns a fresh node. Mutating that node does not update the key; construct a
+new key with `initJwk` to change it. Missing members return `none`, while an
+explicit JSON null returns `some` containing a `JNull` node.
+Use `%key` to serialize a complete key, including extension members, to an
+independent JSON object.
+
+Internally, arbitrary JSON members are stored as encoded strings in a value
+table. Only JSON member lookups decode them. Signing and verification use the
+parsed key fields directly. This ownership guarantee applies to `JWK` and
+`JwkSet`; JWT claims and JOSE headers retain their existing ownership behavior.
+
+Run `nimble unittest` to run the suite, including worker-thread tests, under
+both ARC and ORC.
+
 ## Supported Algorithms (JWA)
 
 [RFC7518 (JWA)][rfc7518] registers

jwt_full.nimble

@@ -1,6 +1,6 @@
 # Package
 
-version       = "0.1.0"
+version       = "0.5.0"
 author        = "Jonathan Bernard"
 description   = "Full JWT, JWS, JWE, and JWK implementation for Nim, compliant with RFCs 7515-7519."
 license       = "GPL-3.0-or-later"
@@ -13,4 +13,5 @@ requires "bearssl"
 requires "https://github.com/yglukhov/bearssl_pkey_decoder"
 
 task unittest, "Run the unit test suites.":
-  exec "nim c -r src/test/unit/runner"
+  exec "nim c -r --threads:on --gc:arc src/test/unit/runner"
+  exec "nim c -r --threads:on --gc:orc src/test/unit/runner"

src/main/jwt_full/claims.nim

@@ -25,25 +25,29 @@ type
   JwtClaims* = object
     rawB64: string
     json: JsonNode
-    iss: Option[string]
-    sub: Option[string]
     aud: Option[string]
     exp: Option[DateTime]
-    nbf: Option[DateTime]
     iat: Option[DateTime]
+    iss: Option[string]
     jti: Option[string]
+    nbf: Option[DateTime]
+    sid: Option[string]
+    sub: Option[string]
+    typ: Option[string]
 
 # Public read-only accessors to JwtClaims members
 # -----------------------------------------------
 
 func rawB64*(c: JwtClaims): string = c.rawB64
-func iss*(c: JwtClaims): Option[string] = c.iss
-func sub*(c: JwtClaims): Option[string] = c.sub
 func aud*(c: JwtClaims): Option[string] = c.aud
 func exp*(c: JwtClaims): Option[DateTime] = c.exp
-func nbf*(c: JwtClaims): Option[DateTime] = c.nbf
 func iat*(c: JwtClaims): Option[DateTime] = c.iat
+func iss*(c: JwtClaims): Option[string] = c.iss
 func jti*(c: JwtClaims): Option[string] = c.jti
+func nbf*(c: JwtClaims): Option[DateTime] = c.nbf
+func sid*(c: JwtClaims): Option[string] = c.sid
+func sub*(c: JwtClaims): Option[string] = c.sub
+func typ*(c: JwtClaims): Option[string] = c.typ
 
 func `[]`*(c: JwtClaims, key: string): Option[JsonNode] =
   ## Generic accessor to claim values by name
@@ -61,13 +65,15 @@ proc initJwtClaims*(n: JsonNode): JwtClaims =
   return JwtClaims(
     rawB64: b64UrlEncode($n),
     json: n,
-    iss: n.optStrVal("iss"),
-    sub: n.optStrVal("sub"),
     aud: n.optStrVal("aud"),
     exp: n.optNumericDate("exp"),
-    nbf: n.optNumericDate("nbf"),
     iat: n.optNumericDate("iat"),
-    jti: n.optStrVal("jtu"))
+    iss: n.optStrVal("iss"),
+    jti: n.optStrVal("jtu"),
+    nbf: n.optNumericDate("nbf"),
+    sid: n.optStrVal("sid"),
+    sub: n.optStrVal("sub"),
+    typ: n.optStrVal("typ"))
 
 proc initJwtClaims*(encoded: string): JwtClaims =
   ## Parse a Base64url-encoded set of claims into a JwtClaims object
@@ -77,13 +83,15 @@ proc initJwtClaims*(encoded: string): JwtClaims =
   result.rawB64 = encoded
 
 proc initJwtClaims*(
-    iss: Option[string] = none[string](),
-    sub: Option[string] = none[string](),
     aud: Option[string] = none[string](),
     exp: Option[DateTime] = none[DateTime](),
-    nbf: Option[DateTime] = none[DateTime](),
     iat: Option[DateTime] = none[DateTime](),
+    iss: Option[string] = none[string](),
     jti: Option[string] = none[string](),
+    nbf: Option[DateTime] = none[DateTime](),
+    sid: Option[string] = none[string](),
+    sub: Option[string] = none[string](),
+    typ: Option[string] = none[string](),
     moreClaims: seq[tuple[k, v: string]] = @[]
   ): JwtClaims =
   ## Convenience method to initialize a new JwtClaims object by specifying
@@ -99,12 +107,14 @@ proc initJwtClaims*(
   let json = newJObject()
   for claim in moreClaims: json[claim.k] = %claim.v
 
-  if iss.isSome: json["iss"] = %iss.get
-  if sub.isSome: json["sub"] = %sub.get
   if aud.isSome: json["aud"] = %aud.get
   if exp.isSome: json["exp"] = %toNumericDate(exp.get)
-  if nbf.isSome: json["nbf"] = %toNumericDate(nbf.get)
   if iat.isSome: json["iat"] = %toNumericDate(iat.get)
+  if iss.isSome: json["iss"] = %iss.get
   if jti.isSome: json["jti"] = %jti.get
+  if nbf.isSome: json["nbf"] = %toNumericDate(nbf.get)
+  if sid.isSome: json["sid"] = %sid.get
+  if sub.isSome: json["sub"] = %sub.get
+  if typ.isSome: json["typ"] = %typ.get
 
   return initJwtClaims(json)

src/main/jwt_full/jwk.nim

@@ -11,7 +11,7 @@
 ##
 ## Nim implementation of the data structures and constants defined in RFC 7518.
 
-import std/json, std/options, std/sequtils, std/strutils
+import std/json, std/options, std/sequtils, std/strutils, std/tables
 
 import ./jwa
 import ./private/jsonutils
@@ -56,7 +56,12 @@ type
     k*: string
 
   JWK* = object
-    json: JsonNode
+    ## Owns its key material and metadata with value semantics. Copies may be
+    ## handed to separate threads; synchronize access to a source being mutated.
+    ## JSON member access returns a fresh node, independent of the key.
+    jsonMembers: Table[string, string]
+      # Keep arbitrary JSON members as encoded values, without JsonNode refs.
+      # Cryptographic operations use the parsed fields below, without decoding.
     kty: string
     use: Option[string]
     key_ops: Option[string]
@@ -96,8 +101,18 @@ func rsaPrv*(jwk: JWK): RsaPrvKey = jwk.rsaPrv
 func octKey*(jwk: JWK): OctetKey = jwk.octKey
 
 func `[]`*(jwk: JWK, key: string): Option[JsonNode] =
-  if jwk.json.hasKey(key): some(jwk.json[key])
-  else: none[JsonNode]()
+  ## Return an independent JSON value for a member, or none if it is absent.
+  if jwk.jsonMembers.hasKey(key):
+    # The string parser only touches a newly allocated in-memory stream, but
+    # its stream-based implementation is not annotated noSideEffect in std/json.
+    {.cast(noSideEffect).}:
+      result = some(parseJson(jwk.jsonMembers[key]))
+
+func `%`*(jwk: JWK): JsonNode =
+  ## Serialize the key and its extension members to an independent JSON object.
+  result = newJObject()
+  for name in jwk.jsonMembers.keys:
+    result[name] = jwk[name].get
 
 # Public Parsing Functions
 # ------------------------
@@ -143,7 +158,9 @@ func parseOctetKey*(n: JsonNode): OctetKey =
   OctetKey(k: n.reqStrVal("k"))
 
 func initJwk*(n: JsonNode): JWK =
-  # TODO: documentation, example, handle encrypted keys (JWEs)
+  ## Parse an owned snapshot of a key, including its extension metadata.
+  ## Later changes to n or to nodes returned by [] do not affect the key.
+  # TODO: example, handle encrypted keys (JWEs)
   case n["kty"].getStr(""):
 
   of $ktyEC:
@@ -179,7 +196,8 @@ func initJwk*(n: JsonNode): JWK =
   else: raise newException(ValueError,
     "Unrecognized or missing kty: '" & n["kty"].getStr("") & "'")
 
-  result.json = n
+  for name, value in n.pairs:
+    result.jsonMembers[name] = $value
   result.use = n.optStrVal("use")
   result.key_ops = n.optStrVal("key_ops")
   result.alg = n.optStrVal("alg")

src/main/jwt_full/jwt.nim

@@ -1,5 +1,5 @@
 # jwt_full/jwt.nim
-# Copyright 2021 Jonathan Bernard
+# Copyright © 2021 Jonathan Bernard
 
 ## ===============================
 ##             jwt
@@ -57,7 +57,7 @@ proc initJWT*(encoded: string): JWT =
       jws: jws)
   else:
     # TODO
-    raise newException(Exception, "not yet implemented")
+    raise newException(Exception, "partial JWT construction is not yet implemented")
 
 proc toJWT*(encoded: string): JWT = initJWT(encoded)
 

src/main/jwt_full/private/crypto/ecdsa.nim

@@ -1,4 +1,3 @@
-import std/tables
 import bearssl, bearssl_pkey_decoder
 
 import ../../encoding
@@ -35,14 +34,14 @@ func fromBearSslCurveConst(curve: int32): EcCurve =
 func initEcPublicKeyObj(curve: EcCurve, q: string): EcPublicKeyObj =
   result = EcPublicKeyObj(curve: curve, q: q)
   result.bearKey.curve = curve.toBearSslCurveConst
-  result.bearKey.q = cast[ptr char](result.q.cstring)
-  result.bearKey.qlen = q.len
+  result.bearKey.q = cast[ptr byte](result.q.cstring)
+  result.bearKey.qlen = uint q.len
 
 func initEcPrivateKeyObj(curve: EcCurve, x: string): EcPrivateKeyObj =
   result = EcPrivateKeyObj(curve: curve, x: x)
   result.bearKey.curve = curve.toBearSslCurveConst
-  result.bearKey.x = cast[ptr char](result.x.cstring)
-  result.bearKey.xlen = x.len
+  result.bearKey.x = cast[ptr byte](result.x.cstring)
+  result.bearKey.xlen = uint x.len
 
 proc toEcPublicKey(jwk: JWK): EcPublicKeyObj =
   ## Convert an ECDSA public key in JWK format to the wrapper for BearSSL's
@@ -66,7 +65,7 @@ proc toEcPublicKey(pem: string): EcPublicKeyObj =
     cast[BearPemDecoderCallback](pkeyDecoderPush))
 
   let k = pkCtx.key.ec
-  return initEcPublicKeyObj(k.curve.fromBearSslCurveConst, $cstring(k.q))
+  return initEcPublicKeyObj(k.curve.fromBearSslCurveConst, $cast[cstring](k.q))
 
 proc toEcPrivateKey(jwk: JWK): EcPrivateKeyObj =
   ## Convert an ECDSA private key in JWK format to the wrapper for BearSSL's
@@ -81,12 +80,12 @@ proc toEcPrivateKey(jwk: JWK): EcPrivateKeyObj =
 
 proc toEcPrivateKey(pem: string): EcPrivateKeyObj =
   var skCtx: SkeyDecoderContext
-  skeyDecoderInit(addr skCtx)
+  skeyDecoderInit(skCtx)
   decodePem(pem, "EC PRIVATE KEY", addr skCtx,
     cast[BearPemDecoderCallback](skeyDecoderPush))
 
   let k = skCtx.key.ec
-  return initEcPrivateKeyObj(k.curve.fromBearSslCurveConst, $cstring(k.x))
+  return initEcPrivateKeyObj(k.curve.fromBearSslCurveConst, $cast[cstring](k.x))
 
 proc getEcHashCfg(alg: JwtAlgorithm): HashCfg =
   let hashAlg = case alg:
@@ -137,11 +136,11 @@ proc bearEcVerify(
   let ecVerifyImpl = ecdsaVrfyRawGetDefault()
   let resultCode = ecVerifyImpl(
     addr ecAllM15,
-    cast[ptr char](unsafeAddr hashed[0]),
-    hashed.len,
+    hashed.cstring,
+    uint hashed.len,
     unsafeAddr key.bearKey,
-    cast[ptr char](unsafeAddr signature[0]),
-    signature.len)
+    signature.cstring,
+    uint signature.len)
 
   result = resultCode == 1
 

src/main/jwt_full/private/crypto/hash.nim

@@ -66,5 +66,5 @@ proc hash*(data: string, alg: HashAlgorithm): string =
   let hashCfg = hashConfig(alg)
   result = newString(hashCfg.size)
   hashCfg.vtable.init(pCtx)
-  hashCfg.vtable.update(pCtx, unsafeAddr data[0], data.len)
-  hashCfg.vtable.output(pCtx, addr result[0])
+  hashCfg.vtable.update(pCtx, data.cstring, uint data.len)
+  hashCfg.vtable.out(pCtx, addr result[0])

src/main/jwt_full/private/crypto/hmac.nim

@@ -26,13 +26,13 @@ proc bearHMAC(message: string, alg: JwtAlgorithm, key: string): string =
   var keyCtx: HmacKeyContext
   var hmacCtx: HmacContext
 
-  hmacKeyInit(addr keyCtx, vtable, key.cstring, key.len)
-  hmacInit(addr hmacCtx, addr keyCtx, 0)
-  hmacUpdate(addr hmacCtx, message.cstring, message.len)
+  hmacKeyInit(keyCtx, vtable, key.cstring, uint key.len)
+  hmacInit(hmacCtx, keyCtx, uint 0)
+  hmacUpdate(hmacCtx, message.cstring, uint message.len)
 
-  let resLen = hmacSize(addr hmacCtx)
+  let resLen = hmacSize(hmacCtx)
   result = newString(resLen)
-  discard hmacOut(addr hmacCtx, addr result[0])
+  discard hmacOut(hmacCtx, addr result[0])
 
 proc hmac*(message: string, alg: JwtAlgorithm, key: string): string =
   return bearHMAC(message, alg, key)

src/main/jwt_full/private/crypto/pem.nim

@@ -3,7 +3,7 @@ import bearssl
 # Taken from  nim-bearssl/decls.nim
 {.pragma: bearSslFunc, cdecl, gcsafe, noSideEffect, raises: [].}
 
-type BearPemDecoderCallback* = proc(keyCtx: pointer, data: pointer, dataLen: int) {.bearSslFunc.}
+type BearPemDecoderCallback* = proc(destCtx: pointer, src: pointer, dataLen: csize_t) {.bearSslFunc.}
 
 proc decodePem*(
     pem: string,
@@ -13,30 +13,30 @@ proc decodePem*(
   ) =
 
   var pemCtx: PemDecoderContext
-  pemDecoderInit(addr pemCtx)
+  pemDecoderInit(pemCtx)
 
-  var offset = 0
-  var bytesRemaining = len(pem)
+  var offset: uint = 0
+  var bytesRemaining: uint = uint len(pem)
   var readingObj = false
 
   while bytesRemaining > 0:
-    let bytesRead = pemDecoderPush(addr pemCtx, unsafeAddr pem[offset], bytesRemaining)
+    let bytesRead = pemDecoderPush(pemCtx, unsafeAddr pem[offset], uint bytesRemaining)
     offset += bytesRead
     bytesRemaining -= bytesRead
 
-    case pemDecoderEvent(addr pemCtx):
+    case pemDecoderEvent(pemCtx):
       of PEM_BEGIN_OBJ:
         if readingObj:
           raise newException(ValueError,
             "Invalid PEM: saw a second BEGIN before seeing END.")
 
-        if pemDecoderName(addr pemCtx) != expectedObjectName:
+        if pemDecoderName(pemCtx) != expectedObjectName:
           raise newException(ValueError,
             "Invalid PEM: expected BEGIN " & expectedObjectName &
-            " but got BEGIN " & $pemDecoderName(addr pemCtx))
+            " but got BEGIN " & $pemDecoderName(pemCtx))
 
         readingObj = true
-        pemDecoderSetdest(addr pemCtx, callback, keyCtx)
+        pemDecoderSetdest(pemCtx, callback, keyCtx)
 
       of PEM_END_OBJ:
         if readingObj: readingObj = false

src/main/jwt_full/private/crypto/rsa.nim

@@ -19,24 +19,24 @@ type
 
 func initRsaPublicKeyObj(n, e: string): RsaPublicKeyObj =
   result = RsaPublicKeyObj(n: n, e: e)
-  result.bearKey.n = cast[ptr char](result.n.cstring)
-  result.bearKey.nlen = result.n.len
-  result.bearKey.e = cast[ptr char](result.e.cstring)
-  result.bearKey.elen = result.e.len
+  result.bearKey.n = cast[ptr byte](result.n.cstring)
+  result.bearKey.nlen = uint result.n.len
+  result.bearKey.e = cast[ptr byte](result.e.cstring)
+  result.bearKey.elen = uint result.e.len
 
 func initRsaPrivateKeyObj(nBitLen: int, p, q, dp, dq, iq: string): RsaPrivateKeyObj =
   result = RsaPrivateKeyObj(p: p, q: q, dp: dp, dq: dq, iq: iq)
   result.bearKey.nBitLen = cast[uint32](nBitLen)
-  result.bearKey.p = cast[ptr char](result.p.cstring)
-  result.bearKey.plen = result.p.len
-  result.bearKey.q = cast[ptr char](result.q.cstring)
-  result.bearKey.qlen = result.q.len
-  result.bearKey.dp = cast[ptr char](result.dp.cstring)
-  result.bearKey.dplen = result.dp.len
-  result.bearKey.dq = cast[ptr char](result.dq.cstring)
-  result.bearKey.dqlen = result.dq.len
-  result.bearKey.iq = cast[ptr char](result.iq.cstring)
-  result.bearKey.iqlen = result.iq.len
+  result.bearKey.p = cast[ptr byte](result.p.cstring)
+  result.bearKey.plen = uint result.p.len
+  result.bearKey.q = cast[ptr byte](result.q.cstring)
+  result.bearKey.qlen = uint result.q.len
+  result.bearKey.dp = cast[ptr byte](result.dp.cstring)
+  result.bearKey.dplen = uint result.dp.len
+  result.bearKey.dq = cast[ptr byte](result.dq.cstring)
+  result.bearKey.dqlen = uint result.dq.len
+  result.bearKey.iq = cast[ptr byte](result.iq.cstring)
+  result.bearKey.iqlen = uint result.iq.len
 
 proc toRsaPublicKey(jwk: JWK): RsaPublicKeyObj =
   ## Convert an RSA public key in JWK format to the wrapper for BearSSL's
@@ -60,7 +60,7 @@ proc toRsaPublicKey(pem: string): RsaPublicKeyObj =
     cast[BearPemDecoderCallback](pkeyDecoderPush))
 
   let k = pkCtx.key.rsa
-  return initRsaPublicKeyObj($cstring(k.n), $cstring(k.e))
+  return initRsaPublicKeyObj($cast[cstring](k.n), $cast[cstring](k.e))
 
 
 proc toRsaPrivateKey(jwk: JWK): RsaPrivateKeyObj =
@@ -111,7 +111,7 @@ proc toRsaPrivateKey(jwk: JWK): RsaPrivateKeyObj =
 
 proc toRsaPrivateKey(pem: string): RsaPrivateKeyObj =
   var skCtx: SkeyDecoderContext
-  skeyDecoderInit(addr skCtx)
+  skeyDecoderInit(skCtx)
   decodePem(pem, "RSA PRIVATE KEY", addr skCtx,
     cast[BearPemDecoderCallback](skeyDecoderPush))
 
@@ -119,11 +119,11 @@ proc toRsaPrivateKey(pem: string): RsaPrivateKeyObj =
 
   return initRsaPrivateKeyObj(
     cast[int](k.nBitLen),
-    $cstring(k.p),
-    $cstring(k.q),
-    $cstring(k.dp),
-    $cstring(k.dq),
-    $cstring(k.iq))
+    $cast[cstring](k.p),
+    $cast[cstring](k.q),
+    $cast[cstring](k.dp),
+    $cast[cstring](k.dq),
+    $cast[cstring](k.iq))
 
 proc getRsaHashCfg(alg: JwtAlgorithm): HashCfg =
   let hashAlg = case alg:
@@ -148,11 +148,11 @@ proc bearRsaSign(
   result = newString((key.bearKey.nBitLen + 7) div 8)
 
   let errCode = rsaSignImpl(
-    cast[ptr char](hashCfg.oid),
-    cast[ptr char](unsafeAddr hashed[0]),
-    hashed.len,
+    cast[ptr byte](hashCfg.oid),
+    cast[ptr byte](unsafeAddr hashed[0]),
+    uint hashed.len,
     unsafeAddr key.bearKey,
-    cast[ptr char](addr result[0]))
+    cast[ptr byte](addr result[0]))
 
   if errCode != 1: raise newException(Exception, "RSA signature failed")
 
@@ -169,12 +169,12 @@ proc bearRsaVerify(
   var recoveredHash = newString(hashCfg.size)
 
   let errCode = rsaVerifyImpl(
-    cast[ptr char](unsafeAddr signature[0]),
-    signature.len,
-    cast[ptr char](hashCfg.oid),
-    hashed.len,
+    cast[ptr byte](unsafeAddr signature[0]),
+    uint signature.len,
+    cast[ptr byte](hashCfg.oid),
+    uint hashed.len,
     unsafeAddr key.bearKey,
-    cast[ptr char](addr recoveredHash[0]))
+    cast[ptr byte](addr recoveredHash[0]))
 
   if errCode != 1: return false
   return hashed == recoveredHash

src/test/unit/runner.nim

@@ -4,5 +4,6 @@ import ./tclaims
 import ./tencoding
 import ./tjoseheader
 import ./tjwk
+import ./tjwkthreads
 import ./tjws
 import ./tjwt

src/test/unit/tjoseheader.nim

@@ -2,6 +2,7 @@ import std/json, std/options, std/unittest
 
 import jwt_full/jwa
 import jwt_full/joseheader
+import jwt_full/jwk
 
 import ../testdata
 
@@ -16,3 +17,16 @@ suite "jwt_full/joseheader":
       h1.rawB64 == rfc7519_S31_HeaderB64
       h2.rawB64 == "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9"
       h3.rawB64 == "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9"
+
+  test "initJoseHeader serializes an embedded JWK":
+    let node = %*{"kty": "oct", "k": "c2VjcmV0", "kid": "original",
+      "metadata": {"labels": ["original"]}}
+    let key = initJwk(node)
+    let header = initJoseHeader(jwk = some(key))
+    check header["jwk"].get == node
+    check header.jwk.get.kid.get == "original"
+    let decoded = initJoseHeader(header.rawB64)
+    check decoded["jwk"].get == node
+    header["jwk"].get["metadata"]["labels"][0].str = "changed"
+    check header.jwk.get["metadata"].get == node["metadata"]
+    check key["metadata"].get == node["metadata"]

src/test/unit/tjwk.nim

@@ -1,4 +1,4 @@
-import std/json, std/options, std/unittest
+import std/json, std/options, std/tables, std/unittest
 
 import jwt_full/jwa, jwt_full/jwk
 
@@ -215,3 +215,88 @@ suite "jwt_full/jwk":
       jwkSet[0].keyKind == EcPrivate
       jwkSet[1].kty == $ktyRSA
       jwkSet[1].keyKind == RsaPrivate
+
+  test "all key variants own their input JSON":
+    let nodes = @[
+      rfc7517A1ExamplePubKeysJson["keys"][0].copy,
+      rfc7517A1ExamplePubKeysJson["keys"][1].copy,
+      rfc7517A2ExamplePrvKeysJson["keys"][0].copy,
+      rfc7517A2ExamplePrvKeysJson["keys"][1].copy,
+      %*{"kty": "oct", "k": "c2VjcmV0", "kid": "octet"}]
+    for node in nodes:
+      node["metadata"] = %*{"labels": ["original"]}
+      let original = node.copy
+      let key = initJwk(node)
+      node["kid"].str = "changed"
+      node["metadata"]["labels"][0].str = "changed"
+      node["newMember"] = %true
+      for name, value in original.pairs:
+        check key[name].get == value
+      check key.kid.get == original["kid"].getStr
+      check key["newMember"].isNone
+
+  test "JSON member lookups return independent values":
+    let key = initJwk(%*{
+      "kty": "oct", "k": "c2VjcmV0", "kid": "original",
+      "metadata": {"labels": ["original"]}})
+    let copied = key
+    let metadata = copied["metadata"].get
+    metadata["labels"][0].str = "changed"
+    let kid = copied["kid"].get
+    kid.str = "changed"
+    check key["metadata"].get["labels"][0].getStr == "original"
+    check copied["metadata"].get["labels"][0].getStr == "original"
+    check key["kid"].get.getStr == "original"
+    check copied["kid"].get.getStr == "original"
+    check copied.kid.get == "original"
+
+  test "JSON serialization round trips without exposing owned state":
+    let node = %*{"kty": "oct", "k": "c2VjcmV0", "kid": "original",
+      "metadata": {"labels": ["original"]}}
+    let key = initJwk(node)
+    let serialized = %key
+    check serialized == node
+    check %initJwk(serialized) == node
+    serialized["metadata"]["labels"][0].str = "changed"
+    check %key == node
+
+  test "member lookup preserves JSON types and missing versus null":
+    let node = %*{
+      "kty": "oct", "k": "c2VjcmV0", "nullValue": nil,
+      "integer": 1234567890123456789'i64, "float": 1.25, "boolean": true,
+      "string": "quotes: \" newline: \n unicode: \u263a",
+      "array": [nil, false, 42, {"nested": []}], "object": {}}
+    let key = initJwk(node)
+    for name, value in node.pairs:
+      check key[name].get.kind == value.kind
+      check key[name].get == value
+    check key["nullValue"].isSome
+    check key["nullValue"].get.kind == JNull
+    check key["missing"].isNone
+    check default(JWK)["missing"].isNone
+
+  test "tables of key sets have independent copies":
+    let node = %*{"keys": [{"kty": "oct", "k": "c2VjcmV0", "kid": "original"}]}
+    let keys = initJwkSet(node)
+    let original = {"issuer": keys}.toTable
+    var copied = original
+    node["keys"][0]["kid"].str = "changed"
+    copied["issuer"][0]["kid"].get.str = "changed"
+    copied["issuer"].add initJwk(%*{"kty": "oct", "k": "c2VjcmV0", "kid": "added"})
+    check keys[0]["kid"].get.getStr == "original"
+    check original["issuer"].len == 1
+    check original["issuer"][0]["kid"].get.getStr == "original"
+    check copied["issuer"].len == 2
+    check copied["issuer"][0]["kid"].get.getStr == "original"
+
+  test "RSA accessors return independent nested value fields":
+    let node = rfc7517A2ExamplePrvKeysJson["keys"][1].copy
+    node["oth"] = %*[{"r": "Aw", "d": "BQ", "t": "Bw"}]
+    let key = initJwk(node)
+    var rsa = key.rsaPrv
+    rsa.n[0] = '!'
+    rsa.p.get[0] = '!'
+    rsa.oth.get[0].r[0] = '!'
+    check key.rsaPrv.n == node["n"].getStr
+    check key.rsaPrv.p.get == node["p"].getStr
+    check key.rsaPrv.oth.get[0].r == "Aw"

src/test/unit/tjwkthreads.nim

@@ -0,0 +1,47 @@
+when compileOption("threads"):
+  import std/[json, options, tables, unittest]
+  import jwt_full
+
+  type
+    KeyCache = Table[string, JwkSet]
+    WorkerInput = tuple[keys: KeyCache, passed: ptr bool]
+
+  proc useKeys(input: WorkerInput) {.thread.} =
+    var keys = input.keys
+    try:
+      for i in 0 ..< 50:
+        let key = keys["issuer"][0]
+        let metadata = key["metadata"].get
+        metadata["labels"][0].str = "worker"
+        var material = key.octKey
+        material.k[0] = '!'
+
+        # Both metadata and parsed key material remain intact after modifying
+        # accessor results. Each worker also signs and verifies with its copy.
+        if key["metadata"].get["labels"][0].getStr != "original": return
+        if key.octKey.k[0] == '!': return
+        let token = sign(payload = "payload",
+          header = initJoseHeader(%*{"alg": "HS256"}), key = key)
+        token.validate(HS256, key)
+
+      keys["issuer"].setLen(0)
+      input.passed[] = true
+    except CatchableError:
+      input.passed[] = false
+
+  suite "jwt_full/jwk thread isolation":
+    test "workers copy key caches and use their keys independently":
+      let node = %*{
+        "kty": "oct", "alg": "HS256", "kid": "original",
+        "k": "MDEyMzQ1Njc4OWFiY2RlZjAxMjM0NTY3ODlhYmNkZWY",
+        "metadata": {"labels": ["original"]}}
+      let original = {"issuer": @[initJwk(node)]}.toTable
+      var workers: array[4, Thread[WorkerInput]]
+      var passed: array[4, bool]
+      for i in 0 ..< workers.len:
+        createThread(workers[i], useKeys, (original, addr passed[i]))
+      joinThreads(workers)
+      check passed == [true, true, true, true]
+      check original["issuer"].len == 1
+      check original["issuer"][0]["metadata"].get == node["metadata"]
+      check original["issuer"][0].octKey.k == node["k"].getStr