diff --git a/packages/next-auth/src/core/lib/oauth/authorization-url.ts b/packages/next-auth/src/core/lib/oauth/authorization-url.ts
index 481a8f61e3..0fc022f9b3 100644
--- a/packages/next-auth/src/core/lib/oauth/authorization-url.ts
+++ b/packages/next-auth/src/core/lib/oauth/authorization-url.ts
@@ -1,8 +1,6 @@
 import { openidClient } from "./client"
 import { oAuth1Client, oAuth1TokenStore } from "./client-legacy"
-import { createState } from "./state-handler"
-import { createNonce } from "./nonce-handler"
-import { createPKCE } from "./pkce-handler"
+import * as checks from "./checks"
 
 import type { AuthorizationParameters } from "openid-client"
 import type { InternalOptions } from "../../types"
@@ -54,24 +52,9 @@ export default async function getAuthorizationUrl({
   const authorizationParams: AuthorizationParameters = params
   const cookies: Cookie[] = []
 
-  const state = await createState(options)
-  if (state) {
-    authorizationParams.state = state.value
-    cookies.push(state.cookie)
-  }
-
-  const nonce = await createNonce(options)
-  if (nonce) {
-    authorizationParams.nonce = nonce.value
-    cookies.push(nonce.cookie)
-  }
-
-  const pkce = await createPKCE(options)
-  if (pkce) {
-    authorizationParams.code_challenge = pkce.code_challenge
-    authorizationParams.code_challenge_method = pkce.code_challenge_method
-    cookies.push(pkce.cookie)
-  }
+  await checks.state.create(options, cookies, authorizationParams)
+  await checks.pkce.create(options, cookies, authorizationParams)
+  await checks.nonce.create(options, cookies, authorizationParams)
 
   const url = client.authorizationUrl(authorizationParams)
 
diff --git a/packages/next-auth/src/core/lib/oauth/callback.ts b/packages/next-auth/src/core/lib/oauth/callback.ts
index 86d6a42d21..3038150bc8 100644
--- a/packages/next-auth/src/core/lib/oauth/callback.ts
+++ b/packages/next-auth/src/core/lib/oauth/callback.ts
@@ -1,12 +1,10 @@
 import { TokenSet } from "openid-client"
 import { openidClient } from "./client"
 import { oAuth1Client, oAuth1TokenStore } from "./client-legacy"
-import { useState } from "./state-handler"
-import { usePKCECodeVerifier } from "./pkce-handler"
-import { useNonce } from "./nonce-handler"
+import * as _checks from "./checks"
 import { OAuthCallbackError } from "../../errors"
 
-import type { CallbackParamsType, OpenIDCallbackChecks } from "openid-client"
+import type { CallbackParamsType } from "openid-client"
 import type { LoggerInstance, Profile } from "../../.."
 import type { OAuthChecks, OAuthConfig } from "../../../providers"
 import type { InternalOptions } from "../../types"
@@ -73,24 +71,9 @@ export default async function oAuthCallback(params: {
     const checks: OAuthChecks = {}
     const resCookies: Cookie[] = []
 
-    const state = await useState(cookies?.[options.cookies.state.name], options)
-    if (state) {
-      checks.state = state.value
-      resCookies.push(state.cookie)
-    }
-
-    const nonce = await useNonce(cookies?.[options.cookies.nonce.name], options)
-    if (nonce && provider.idToken) {
-      ;(checks as OpenIDCallbackChecks).nonce = nonce.value
-      resCookies.push(nonce.cookie)
-    }
-
-    const codeVerifier = cookies?.[options.cookies.pkceCodeVerifier.name]
-    const pkce = await usePKCECodeVerifier(codeVerifier, options)
-    if (pkce) {
-      checks.code_verifier = pkce.codeVerifier
-      resCookies.push(pkce.cookie)
-    }
+    await _checks.state.use(cookies, resCookies, options, checks)
+    await _checks.pkce.use(cookies, resCookies, options, checks)
+    await _checks.nonce.use(cookies, resCookies, options, checks)
 
     const params: CallbackParamsType = {
       ...client.callbackParams({
diff --git a/packages/next-auth/src/core/lib/oauth/checks.ts b/packages/next-auth/src/core/lib/oauth/checks.ts
new file mode 100644
index 0000000000..37d5a84be3
--- /dev/null
+++ b/packages/next-auth/src/core/lib/oauth/checks.ts
@@ -0,0 +1,181 @@
+import {
+  AuthorizationParameters,
+  generators,
+  OpenIDCallbackChecks,
+} from "openid-client"
+import * as jwt from "../../../jwt"
+
+import type { RequestInternal } from "../.."
+import type { CookiesOptions, InternalOptions } from "../../types"
+import type { Cookie } from "../cookie"
+import { OAuthChecks } from "src/providers"
+
+/** Returns a signed cookie. */
+export async function signCookie(
+  type: keyof CookiesOptions,
+  value: string,
+  maxAge: number,
+  options: InternalOptions<"oauth">
+): Promise<Cookie> {
+  const { cookies, logger } = options
+
+  logger.debug(`CREATE_${type.toUpperCase()}`, { value, maxAge })
+
+  const expires = new Date()
+  expires.setTime(expires.getTime() + maxAge * 1000)
+  return {
+    name: cookies[type].name,
+    value: await jwt.encode({ ...options.jwt, maxAge, token: { value } }),
+    options: { ...cookies[type].options, expires },
+  }
+}
+
+const PKCE_MAX_AGE = 60 * 15 // 15 minutes in seconds
+export const PKCE_CODE_CHALLENGE_METHOD = "S256"
+export const pkce = {
+  async create(
+    options: InternalOptions<"oauth">,
+    cookies: Cookie[],
+    resParams: AuthorizationParameters
+  ) {
+    if (!options.provider?.checks?.includes("pkce")) return
+    const code_verifier = generators.codeVerifier()
+    const value = generators.codeChallenge(code_verifier)
+    resParams.code_challenge = value
+    resParams.code_challenge_method = PKCE_CODE_CHALLENGE_METHOD
+
+    const maxAge =
+      options.cookies.pkceCodeVerifier.options.maxAge ?? PKCE_MAX_AGE
+
+    cookies.push(
+      await signCookie("pkceCodeVerifier", code_verifier, maxAge, options)
+    )
+  },
+  /**
+   * Returns code_verifier if the provider is configured to use PKCE,
+   * and clears the container cookie afterwards.
+   * An error is thrown if the code_verifier is missing or invalid.
+   * @see https://www.rfc-editor.org/rfc/rfc7636
+   * @see https://danielfett.de/2020/05/16/pkce-vs-nonce-equivalent-or-not/#pkce
+   */
+  async use(
+    cookies: RequestInternal["cookies"],
+    resCookies: Cookie[],
+    options: InternalOptions<"oauth">,
+    checks: OAuthChecks
+  ): Promise<string | undefined> {
+    if (!options.provider?.checks?.includes("pkce")) return
+
+    const codeVerifier = cookies?.[options.cookies.pkceCodeVerifier.name]
+
+    if (!codeVerifier)
+      throw new TypeError("PKCE code_verifier cookie was missing.")
+
+    const value = (await jwt.decode({
+      ...options.jwt,
+      token: codeVerifier,
+    })) as any
+
+    if (!value?.value)
+      throw new TypeError("PKCE code_verifier value could not be parsed.")
+
+    resCookies.push({
+      name: options.cookies.pkceCodeVerifier.name,
+      value: "",
+      options: { ...options.cookies.pkceCodeVerifier.options, maxAge: 0 },
+    })
+
+    checks.code_verifier = value.value
+  },
+}
+
+const STATE_MAX_AGE = 60 * 15 // 15 minutes in seconds
+export const state = {
+  async create(
+    options: InternalOptions<"oauth">,
+    cookies: Cookie[],
+    resParams: AuthorizationParameters
+  ) {
+    if (!options.provider.checks?.includes("state")) return
+    const value = generators.state()
+    resParams.state = value
+    const maxAge = options.cookies.state.options.maxAge ?? STATE_MAX_AGE
+    cookies.push(await signCookie("state", value, maxAge, options))
+  },
+  /**
+   * Returns state if the provider is configured to use state,
+   * and clears the container cookie afterwards.
+   * An error is thrown if the state is missing or invalid.
+   * @see https://www.rfc-editor.org/rfc/rfc6749#section-10.12
+   * @see https://www.rfc-editor.org/rfc/rfc6749#section-4.1.1
+   */
+  async use(
+    cookies: RequestInternal["cookies"],
+    resCookies: Cookie[],
+    options: InternalOptions<"oauth">,
+    checks: OAuthChecks
+  ) {
+    if (!options.provider.checks?.includes("state")) return
+
+    const state = cookies?.[options.cookies.state.name]
+
+    if (!state) throw new TypeError("State cookie was missing.")
+
+    const value = (await jwt.decode({ ...options.jwt, token: state })) as any
+
+    if (!value?.value) throw new TypeError("State value could not be parsed.")
+
+    resCookies.push({
+      name: options.cookies.state.name,
+      value: "",
+      options: { ...options.cookies.state.options, maxAge: 0 },
+    })
+
+    checks.state = value.value
+  },
+}
+
+const NONCE_MAX_AGE = 60 * 15 // 15 minutes in seconds
+export const nonce = {
+  async create(
+    options: InternalOptions<"oauth">,
+    cookies: Cookie[],
+    resParams: AuthorizationParameters
+  ) {
+    if (!options.provider.checks?.includes("nonce")) return
+    const value = generators.nonce()
+    resParams.nonce = value
+    const maxAge = options.cookies.nonce.options.maxAge ?? NONCE_MAX_AGE
+    cookies.push(await signCookie("nonce", value, maxAge, options))
+  },
+  /**
+   * Returns nonce if the provider is configured to use nonce,
+   * and clears the container cookie afterwards.
+   * An error is thrown if the nonce is missing or invalid.
+   * @see https://openid.net/specs/openid-connect-core-1_0.html#NonceNotes
+   * @see https://danielfett.de/2020/05/16/pkce-vs-nonce-equivalent-or-not/#nonce
+   */
+  async use(
+    cookies: RequestInternal["cookies"],
+    resCookies: Cookie[],
+    options: InternalOptions<"oauth">,
+    checks: OpenIDCallbackChecks
+  ): Promise<string | undefined> {
+    if (!options.provider?.checks?.includes("nonce")) return
+
+    const nonce = cookies?.[options.cookies.nonce.name]
+    if (!nonce) throw new TypeError("Nonce cookie was missing.")
+
+    const value = (await jwt.decode({ ...options.jwt, token: nonce })) as any
+
+    if (!value?.value) throw new TypeError("Nonce value could not be parsed.")
+
+    resCookies.push({
+      name: options.cookies.nonce.name,
+      value: "",
+      options: { ...options.cookies.nonce.options, maxAge: 0 },
+    })
+
+    checks.nonce = value.value
+  },
+}
diff --git a/packages/next-auth/src/core/lib/oauth/nonce-handler.ts b/packages/next-auth/src/core/lib/oauth/nonce-handler.ts
deleted file mode 100644
index cc7aab362f..0000000000
--- a/packages/next-auth/src/core/lib/oauth/nonce-handler.ts
+++ /dev/null
@@ -1,75 +0,0 @@
-import * as jwt from "../../../jwt"
-import { generators } from "openid-client"
-import type { InternalOptions } from "../../types"
-import type { Cookie } from "../cookie"
-
-const NONCE_MAX_AGE = 60 * 15 // 15 minutes in seconds
-
-/** 
- * Returns nonce if the provider supports it
- * and saves it in a cookie */
-export async function createNonce(options: InternalOptions<"oauth">): Promise<
-  | undefined
-  | {
-      value: string
-      cookie: Cookie
-    }
-> {
-  const { cookies, logger, provider } = options
-  if (!provider.checks?.includes("nonce")) {
-    // Provider does not support nonce, return nothing.
-    return
-  }
-
-  const nonce = generators.nonce()
-
-  const expires = new Date()
-  expires.setTime(expires.getTime() + NONCE_MAX_AGE * 1000)
-
-  // Encrypt nonce and save it to an encrypted cookie
-  const encryptedNonce = await jwt.encode({
-    ...options.jwt,
-    maxAge: NONCE_MAX_AGE,
-    token: { nonce },
-  })
-
-  logger.debug("CREATE_ENCRYPTED_NONCE", {
-    nonce,
-    maxAge: NONCE_MAX_AGE,
-  })
-
-  return {
-    cookie: {
-      name: cookies.nonce.name,
-      value: encryptedNonce,
-      options: { ...cookies.nonce.options, expires },
-    },
-    value: nonce,
-  }
-}
-
-/**
- * Returns nonce from if the provider supports nonce,
- * and clears the container cookie afterwards.
- */
-export async function useNonce(
-  nonce: string | undefined,
-  options: InternalOptions<"oauth">
-): Promise<{ value: string; cookie: Cookie } | undefined> {
-  const { cookies, provider } = options
-
-  if (!provider?.checks?.includes("nonce") || !nonce) {
-    return
-  }
-
-  const value = (await jwt.decode({...options.jwt, token: nonce })) as any
-
-  return {
-    value: value?.nonce ?? undefined,
-    cookie: {
-      name: cookies.nonce.name,
-      value: "",
-      options: { ...cookies.nonce.options, maxAge: 0 },
-    },
-  }
-}
diff --git a/packages/next-auth/src/core/lib/oauth/pkce-handler.ts b/packages/next-auth/src/core/lib/oauth/pkce-handler.ts
deleted file mode 100644
index 0e279055ef..0000000000
--- a/packages/next-auth/src/core/lib/oauth/pkce-handler.ts
+++ /dev/null
@@ -1,86 +0,0 @@
-import * as jwt from "../../../jwt"
-import { generators } from "openid-client"
-import type { InternalOptions } from "../../types"
-import type { Cookie } from "../cookie"
-
-const PKCE_CODE_CHALLENGE_METHOD = "S256"
-const PKCE_MAX_AGE = 60 * 15 // 15 minutes in seconds
-
-/**
- * Returns `code_challenge` and `code_challenge_method`
- * and saves them in a cookie.
- */
-export async function createPKCE(options: InternalOptions<"oauth">): Promise<
-  | undefined
-  | {
-      code_challenge: string
-      code_challenge_method: "S256"
-      cookie: Cookie
-    }
-> {
-  const { cookies, logger, provider } = options
-  if (!provider.checks?.includes("pkce")) {
-    // Provider does not support PKCE, return nothing.
-    return
-  }
-  const code_verifier = generators.codeVerifier()
-  const code_challenge = generators.codeChallenge(code_verifier)
-
-  const maxAge = cookies.pkceCodeVerifier.options.maxAge ?? PKCE_MAX_AGE
-
-  const expires = new Date()
-  expires.setTime(expires.getTime() + maxAge * 1000)
-
-  // Encrypt code_verifier and save it to an encrypted cookie
-  const encryptedCodeVerifier = await jwt.encode({
-    ...options.jwt,
-    maxAge,
-    token: { code_verifier },
-  })
-
-  logger.debug("CREATE_PKCE_CHALLENGE_VERIFIER", {
-    code_challenge,
-    code_challenge_method: PKCE_CODE_CHALLENGE_METHOD,
-    code_verifier,
-    maxAge,
-  })
-
-  return {
-    code_challenge,
-    code_challenge_method: PKCE_CODE_CHALLENGE_METHOD,
-    cookie: {
-      name: cookies.pkceCodeVerifier.name,
-      value: encryptedCodeVerifier,
-      options: { ...cookies.pkceCodeVerifier.options, expires },
-    },
-  }
-}
-
-/**
- * Returns code_verifier if provider uses PKCE,
- * and clears the container cookie afterwards.
- */
-export async function usePKCECodeVerifier(
-  codeVerifier: string | undefined,
-  options: InternalOptions<"oauth">
-): Promise<{ codeVerifier: string; cookie: Cookie } | undefined> {
-  const { cookies, provider } = options
-
-  if (!provider?.checks?.includes("pkce") || !codeVerifier) {
-    return
-  }
-
-  const pkce = (await jwt.decode({
-    ...options.jwt,
-    token: codeVerifier,
-  })) as any
-
-  return {
-    codeVerifier: pkce?.code_verifier ?? undefined,
-    cookie: {
-      name: cookies.pkceCodeVerifier.name,
-      value: "",
-      options: { ...cookies.pkceCodeVerifier.options, maxAge: 0 },
-    },
-  }
-}
diff --git a/packages/next-auth/src/core/lib/oauth/state-handler.ts b/packages/next-auth/src/core/lib/oauth/state-handler.ts
deleted file mode 100644
index 80894f0de6..0000000000
--- a/packages/next-auth/src/core/lib/oauth/state-handler.ts
+++ /dev/null
@@ -1,66 +0,0 @@
-import { generators } from "openid-client"
-
-import type { InternalOptions } from "../../types"
-import type { Cookie } from "../cookie"
-
-const STATE_MAX_AGE = 60 * 15 // 15 minutes in seconds
-
-/** Returns state if the provider supports it */
-export async function createState(
-  options: InternalOptions<"oauth">
-): Promise<{ cookie: Cookie; value: string } | undefined> {
-  const { logger, provider, jwt, cookies } = options
-
-  if (!provider.checks?.includes("state")) {
-    // Provider does not support state, return nothing
-    return
-  }
-
-  const state = generators.state()
-  const maxAge = cookies.state.options.maxAge ?? STATE_MAX_AGE
-
-  const encodedState = await jwt.encode({
-    ...jwt,
-    maxAge,
-    token: { state },
-  })
-
-  logger.debug("CREATE_STATE", { state, maxAge })
-
-  const expires = new Date()
-  expires.setTime(expires.getTime() + maxAge * 1000)
-  return {
-    value: state,
-    cookie: {
-      name: cookies.state.name,
-      value: encodedState,
-      options: { ...cookies.state.options, expires },
-    },
-  }
-}
-
-/**
- * Returns state from if the provider supports states,
- * and clears the container cookie afterwards.
- */
-export async function useState(
-  state: string | undefined,
-  options: InternalOptions<"oauth">
-): Promise<{ value: string; cookie: Cookie } | undefined> {
-  const { cookies, provider, jwt } = options
-
-  if (!provider.checks?.includes("state")) return
-
-  if (!state) throw new Error("No state provided")
-
-  const value = (await jwt.decode({ ...options.jwt, token: state })) as any
-
-  return {
-    value: value?.state ?? undefined,
-    cookie: {
-      name: cookies.state.name,
-      value: "",
-      options: { ...cookies.pkceCodeVerifier.options, maxAge: 0 },
-    },
-  }
-}