feat(auth): per-account X25519 identity keypair (Phase A1, #3) #6

Merged
alvaro merged 1 commit from feat/3-phase-a1-x25519-keypair into main 2026-07-19 00:00:29 +00:00
10 changed files with 437 additions and 5 deletions

1
.gitignore vendored
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@ -2,6 +2,7 @@
.env.local
.env.*.local
.forgejo-token
.zcode/
node_modules/
dist/
target/

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@ -27,6 +27,11 @@ pub struct RegisterRequest {
/// Wrapped DEK (base64 ciphertext) — encrypted under the recovery KEK
pub recovery_wrapped_dek: Option<String>,
pub recovery_wrapped_dek_iv: Option<String>,
/// Account X25519 identity public key (base64 raw). Plaintext.
pub identity_public_key: Option<String>,
/// Account X25519 identity private key, wrapped under the account DEK.
pub identity_private_key_wrapped: Option<String>,
pub identity_private_key_wrapped_iv: Option<String>,
}
#[derive(Debug, Serialize)]
@ -40,6 +45,12 @@ pub struct AuthResponse {
/// user has no wrapped DEK (legacy/pre-recovery accounts).
pub wrapped_dek: Option<String>,
pub wrapped_dek_iv: Option<String>,
/// Account X25519 identity keypair. The public key is plaintext; the
/// private key is an opaque ciphertext blob wrapped under the account DEK.
/// Absent for accounts that predate the identity-keypair feature.
pub identity_public_key: Option<String>,
pub identity_private_key_wrapped: Option<String>,
pub identity_private_key_wrapped_iv: Option<String>,
}
pub async fn register(
@ -108,6 +119,11 @@ pub async fn register(
user.recovery_wrapped_dek = req.recovery_wrapped_dek.clone();
user.recovery_wrapped_dek_iv = req.recovery_wrapped_dek_iv.clone();
user.recovery_enabled = req.recovery_wrapped_dek.is_some();
// Store the X25519 identity keypair (public plaintext, private wrapped
// under the account DEK — server stores verbatim, cannot decrypt).
user.identity_public_key = req.identity_public_key;
user.identity_private_key_wrapped = req.identity_private_key_wrapped;
user.identity_private_key_wrapped_iv = req.identity_private_key_wrapped_iv;
// Get token_version before saving
let token_version = user.token_version;
@ -203,6 +219,9 @@ pub async fn register(
username: user.username.clone(),
wrapped_dek: user.wrapped_dek.clone(),
wrapped_dek_iv: user.wrapped_dek_iv.clone(),
identity_public_key: user.identity_public_key.clone(),
identity_private_key_wrapped: user.identity_private_key_wrapped.clone(),
identity_private_key_wrapped_iv: user.identity_private_key_wrapped_iv.clone(),
};
(StatusCode::CREATED, Json(response)).into_response()
@ -413,6 +432,9 @@ pub async fn login(
username: user.username.clone(),
wrapped_dek: user.wrapped_dek.clone(),
wrapped_dek_iv: user.wrapped_dek_iv.clone(),
identity_public_key: user.identity_public_key.clone(),
identity_private_key_wrapped: user.identity_private_key_wrapped.clone(),
identity_private_key_wrapped_iv: user.identity_private_key_wrapped_iv.clone(),
};
(StatusCode::OK, Json(response)).into_response()

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@ -37,6 +37,21 @@ pub struct User {
#[serde(skip_serializing_if = "Option::is_none")]
pub recovery_wrapped_dek_iv: Option<String>,
/// Account X25519 identity public key (base64 raw). Plaintext — public keys
/// are not secret. Other accounts wrap profile DEKs to this key (Phase B,
/// see docs/adr/multi-person-sharing.md). Generated client-side at
/// registration.
#[serde(skip_serializing_if = "Option::is_none")]
pub identity_public_key: Option<String>,
/// Account X25519 identity private key, wrapped (AES-256-GCM encrypted)
/// under the account DEK. The server stores this verbatim and cannot
/// decrypt it. The client unwraps it at login after unwrapping the DEK.
#[serde(skip_serializing_if = "Option::is_none")]
pub identity_private_key_wrapped: Option<String>,
#[serde(skip_serializing_if = "Option::is_none")]
pub identity_private_key_wrapped_iv: Option<String>,
/// Token version for invalidating all tokens on password change
pub token_version: i32,
@ -93,6 +108,9 @@ impl User {
wrapped_dek_iv: None,
recovery_wrapped_dek: None,
recovery_wrapped_dek_iv: None,
identity_public_key: None,
identity_private_key_wrapped: None,
identity_private_key_wrapped_iv: None,
token_version: 0,
created_at: now,
last_active: now,

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@ -287,6 +287,80 @@ async fn password_change_invalidates_existing_tokens() {
common::drop_test_db(&db_name).await;
}
#[tokio::test]
async fn identity_keypair_round_trips_through_register_and_login() {
// Phase A1 (#3): the X25519 identity keypair fields (public plaintext,
// private wrapped under the account DEK) are stored verbatim at register
// and echoed back on login. The server never inspects or derives them.
let (app, db_name) = require_app!(common::app_for_test().await);
let email = unique_email();
// Opaque blobs — the server treats these as base64 strings, nothing more.
let public_key = "base64-x25519-public-key-for-test";
let priv_wrapped = "base64-wrapped-priv-ciphertext";
let priv_wrapped_iv = "base64-12-byte-iv";
let (status, body) = common::send_json(
&app,
"POST",
"/api/auth/register",
Some(json!({
"email": email,
"username": "tester",
"password": "supersecret",
"identity_public_key": public_key,
"identity_private_key_wrapped": priv_wrapped,
"identity_private_key_wrapped_iv": priv_wrapped_iv,
})),
None,
)
.await;
assert_eq!(status, 201, "register should return 201, body: {body}");
assert_eq!(body["identity_public_key"], public_key);
assert_eq!(body["identity_private_key_wrapped"], priv_wrapped);
assert_eq!(body["identity_private_key_wrapped_iv"], priv_wrapped_iv);
// Login must echo the same stored values.
let (status, body) = common::send_json(
&app,
"POST",
"/api/auth/login",
Some(json!({ "email": email, "password": "supersecret" })),
None,
)
.await;
assert_eq!(status, 200, "login should return 200, body: {body}");
assert_eq!(body["identity_public_key"], public_key);
assert_eq!(body["identity_private_key_wrapped"], priv_wrapped);
assert_eq!(body["identity_private_key_wrapped_iv"], priv_wrapped_iv);
common::drop_test_db(&db_name).await;
}
#[tokio::test]
async fn register_without_identity_keypair_stays_optional() {
// Backward compat: existing clients that don't send identity fields must
// still register successfully, and the fields are absent from the response.
let (app, db_name) = require_app!(common::app_for_test().await);
let email = unique_email();
let (status, body) = common::send_json(
&app,
"POST",
"/api/auth/register",
Some(json!({ "email": email, "username": "tester", "password": "supersecret" })),
None,
)
.await;
assert_eq!(status, 201, "register should return 201, body: {body}");
assert!(
body.get("identity_public_key").is_none() || body["identity_public_key"].is_null(),
"identity_public_key should be absent when not provided: {body}"
);
common::drop_test_db(&db_name).await;
}
// ---- helpers ----
fn unique_email() -> String {

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@ -9,8 +9,30 @@ import {
setEncKey,
clearEncKey,
hasEncKey,
generateIdentityKeyPair,
wrapIdentityPrivateKey,
unwrapIdentityPrivateKey,
setIdentityPrivate,
clearIdentityPrivate,
hasIdentityPrivate,
} from './index';
/** X25519 in Web Crypto is a recent addition (Node 16+, modern browsers). Some
* test runtimes (older jsdom/Node) may not implement it; detect once and skip
* the identity-keypair tests rather than fail spuriously. */
async function x25519Supported(): Promise<boolean> {
try {
await crypto.subtle.generateKey(
{ name: 'ECDH', namedCurve: 'X25519' },
true,
['deriveBits'],
);
return true;
} catch {
return false;
}
}
describe('zero-knowledge crypto lifecycle', () => {
const password = 'my-secret-password';
const recoveryPhrase = 'my-recovery-phrase';
@ -99,3 +121,106 @@ describe('zero-knowledge crypto lifecycle', () => {
await expect(decryptJson(encrypted, setupB.dek)).rejects.toThrow();
});
});
describe('account X25519 identity keypair (Phase A1)', () => {
const password = 'my-secret-password';
it('full lifecycle: generate → wrap → unlock DEK → unwrap → deriveBits', async () => {
if (!(await x25519Supported())) {
console.log('[crypto] skipped (X25519 unsupported in this runtime)');
return;
}
// 1. Register: set up the account DEK and generate the identity keypair.
const setup = await setupEncryption(password);
const { publicKey, privateKey } = await generateIdentityKeyPair();
expect(publicKey).not.toBe('');
setIdentityPrivate(privateKey);
expect(hasIdentityPrivate()).toBe(true);
// 2. Wrap the private key under the account DEK and "store" it.
const wrapped = await wrapIdentityPrivateKey(privateKey, setup.dek);
expect(wrapped.data).not.toBe('');
// 3. Simulate page reload: both keys are lost from memory.
clearIdentityPrivate();
expect(hasIdentityPrivate()).toBe(false);
// 4. Unlock the DEK with the password (unlock screen flow).
const { dek } = await unlockWithPassword(password, setup.passwordWrappedDek);
// 5. Unwrap the identity private key from the stored wrapped form.
const recovered = await unwrapIdentityPrivateKey(wrapped, dek);
setIdentityPrivate(recovered);
expect(hasIdentityPrivate()).toBe(true);
// 6. The recovered private key is a USABLE X25519 key: it can derive a
// shared secret against the original public key. Import the public key
// and ECDH-derive — this proves the round-trip preserved a working key.
const pubBytes = Uint8Array.from(atob(publicKey), (c) => c.charCodeAt(0));
const pubKey = await crypto.subtle.importKey(
'raw',
pubBytes as BufferSource,
{ name: 'ECDH', namedCurve: 'X25519' },
false,
[],
);
const sharedSecret = await crypto.subtle.deriveBits(
{ name: 'ECDH', public: pubKey },
recovered,
256,
);
expect(sharedSecret.byteLength).toBe(32);
clearIdentityPrivate();
});
it('a wrapped private key cannot be unwrapped with the wrong DEK', async () => {
if (!(await x25519Supported())) {
console.log('[crypto] skipped (X25519 unsupported in this runtime)');
return;
}
// DEK for account A; a different DEK for account B.
const setupA = await setupEncryption('user-a-password');
const setupB = await setupEncryption('user-b-password');
const { privateKey } = await generateIdentityKeyPair();
const wrapped = await wrapIdentityPrivateKey(privateKey, setupA.dek);
// User B's DEK cannot unwrap user A's identity private key.
await expect(unwrapIdentityPrivateKey(wrapped, setupB.dek)).rejects.toThrow();
});
it('two identity keypairs derive different shared secrets with the same peer', async () => {
if (!(await x25519Supported())) {
console.log('[crypto] skipped (X25519 unsupported in this runtime)');
return;
}
// Sanity: distinct keypairs must produce distinct ECDH outputs.
const peer = await generateIdentityKeyPair();
const peerPubBytes = Uint8Array.from(atob(peer.publicKey), (c) => c.charCodeAt(0));
const peerPub = await crypto.subtle.importKey(
'raw',
peerPubBytes as BufferSource,
{ name: 'ECDH', namedCurve: 'X25519' },
false,
[],
);
const a = await generateIdentityKeyPair();
const b = await generateIdentityKeyPair();
const secretA = await crypto.subtle.deriveBits(
{ name: 'ECDH', public: peerPub },
a.privateKey,
256,
);
const secretB = await crypto.subtle.deriveBits(
{ name: 'ECDH', public: peerPub },
b.privateKey,
256,
);
const aHex = Array.from(new Uint8Array(secretA)).map((x) => x.toString(16)).join('');
const bHex = Array.from(new Uint8Array(secretB)).map((x) => x.toString(16)).join('');
expect(aHex).not.toBe(bHex);
});
});

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@ -8,10 +8,17 @@ export {
setupEncryption,
unlockWithPassword,
unlockWithRecovery,
generateIdentityKeyPair,
wrapIdentityPrivateKey,
unwrapIdentityPrivateKey,
setEncKey,
getEncKey,
clearEncKey,
hasEncKey,
setIdentityPrivate,
getIdentityPrivate,
clearIdentityPrivate,
hasIdentityPrivate,
AUTH_SALT,
PASSWORD_KEK_SALT,
RECOVERY_KEK_SALT,

View file

@ -185,6 +185,62 @@ export async function unlockWithRecovery(
return unwrapDek(recoveryWrappedDek, recoveryKek);
}
// ---------------------------------------------------------------------------
// Account X25519 identity keypair (Phase A1, multi-person sharing prep).
//
// Each account gets an X25519 keypair at registration. The PUBLIC half is
// stored in plaintext (public keys are not secret); other accounts will wrap
// profile DEKs to it in Phase B. The PRIVATE half is wrapped (AES-GCM
// encrypted) under the account DEK and stored on the server as opaque
// ciphertext. The server never sees the private key.
//
// See docs/adr/multi-person-sharing.md §1.
// ---------------------------------------------------------------------------
/** Generate an X25519 keypair for the account. Returns the public key as a
* base64 raw string (for the server to store) and the private key as a
* CryptoKey (kept in memory, wrapped before upload). */
export async function generateIdentityKeyPair(): Promise<{
publicKey: string;
privateKey: CryptoKey;
}> {
const { publicKey, privateKey } = (await crypto.subtle.generateKey(
{ name: 'ECDH', namedCurve: 'X25519' },
true, // extractable so we can export the private key for wrapping
['deriveBits'],
)) as CryptoKeyPair;
const rawPublic = await crypto.subtle.exportKey('raw', publicKey);
return { publicKey: base64(new Uint8Array(rawPublic)), privateKey };
}
/** Wrap (encrypt) the X25519 private key under the account DEK. The DEK is an
* AES-GCM key, so we reuse the string-cipher from cipher.ts: export the private
* key to raw bytes, base64-encode, and encrypt. */
export async function wrapIdentityPrivateKey(
privateKey: CryptoKey,
dek: CryptoKey,
): Promise<CipherPayload> {
const rawPrivate = await crypto.subtle.exportKey('raw', privateKey);
return encrypt(base64(new Uint8Array(rawPrivate)), dek);
}
/** Unwrap (decrypt) the X25519 private key from its DEK-wrapped form. Inverse
* of wrapIdentityPrivateKey. The result is importable for ECDH deriveBits. */
export async function unwrapIdentityPrivateKey(
payload: CipherPayload,
dek: CryptoKey,
): Promise<CryptoKey> {
const rawPrivateB64 = await decrypt(payload, dek);
const rawPrivate = Uint8Array.from(atob(rawPrivateB64), (c) => c.charCodeAt(0));
return crypto.subtle.importKey(
'raw',
rawPrivate as BufferSource,
{ name: 'ECDH', namedCurve: 'X25519' },
true, // extractable so it can be re-wrapped if ever needed
['deriveBits'],
);
}
// ---------------------------------------------------------------------------
// In-memory key store (unchanged from Phase 1)
// ---------------------------------------------------------------------------
@ -207,6 +263,30 @@ export function hasEncKey(): boolean {
return currentEncKey !== null;
}
// ---------------------------------------------------------------------------
// In-memory identity-private-key store (Phase A1). Same lifecycle as the DEK:
// held only for the authenticated session, cleared on logout, re-derived from
// the wrapped form (under the account DEK) on unlock. Not consumed until Phase B.
// ---------------------------------------------------------------------------
let currentIdentityPrivate: CryptoKey | null = null;
export function setIdentityPrivate(key: CryptoKey): void {
currentIdentityPrivate = key;
}
export function getIdentityPrivate(): CryptoKey | null {
return currentIdentityPrivate;
}
export function clearIdentityPrivate(): void {
currentIdentityPrivate = null;
}
export function hasIdentityPrivate(): boolean {
return currentIdentityPrivate !== null;
}
// ---------------------------------------------------------------------------
// Backward compat: the old deriveAuthAndEncKeys (Phase 1 direct-from-password
// enc key). Kept for tests; new code uses setupEncryption/unlockWithPassword.

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@ -12,11 +12,23 @@ import {
} from '@mui/material';
import { Lock as LockIcon } from '@mui/icons-material';
import { useAuthStore } from '../store/useStore';
import { unlockWithPassword, deriveAuthAndEncKeys, setEncKey } from '../crypto';
import {
unlockWithPassword,
deriveAuthAndEncKeys,
unwrapIdentityPrivateKey,
setEncKey,
setIdentityPrivate,
} from '../crypto';
export const UnlockPage: FC = () => {
const navigate = useNavigate();
const { wrapped_dek, wrapped_dek_iv, user } = useAuthStore();
const {
wrapped_dek,
wrapped_dek_iv,
identity_private_key_wrapped,
identity_private_key_wrapped_iv,
user,
} = useAuthStore();
const [password, setPassword] = useState('');
const [error, setError] = useState('');
const [unlocking, setUnlocking] = useState(false);
@ -27,13 +39,32 @@ export const UnlockPage: FC = () => {
setUnlocking(true);
try {
let dek;
if (wrapped_dek && wrapped_dek_iv) {
// Wrapped-DEK model: unwrap the DEK using the password.
const { dek } = await unlockWithPassword(password, {
({ dek } = await unlockWithPassword(password, {
data: wrapped_dek,
iv: wrapped_dek_iv,
});
}));
setEncKey(dek);
// Phase A1: with the DEK available, also unwrap the X25519 identity
// private key into in-memory storage. Non-fatal if it fails (e.g.
// legacy accounts without an identity keypair).
if (identity_private_key_wrapped && identity_private_key_wrapped_iv) {
try {
const identityPrivate = await unwrapIdentityPrivateKey(
{
data: identity_private_key_wrapped,
iv: identity_private_key_wrapped_iv,
},
dek,
);
setIdentityPrivate(identityPrivate);
} catch {
// Wrapped private key present but undecryptable — ignore; Phase B
// features will surface a re-setup need.
}
}
} else {
// Phase 1 compat: derive the key directly from the password.
const { encKey } = await deriveAuthAndEncKeys(password);

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@ -6,8 +6,13 @@ import {
unlockWithPassword,
unlockWithRecovery,
rewrapDek,
generateIdentityKeyPair,
wrapIdentityPrivateKey,
unwrapIdentityPrivateKey,
setEncKey,
clearEncKey,
clearIdentityPrivate,
setIdentityPrivate,
getEncKey,
encryptJson,
decryptJson,
@ -38,6 +43,12 @@ interface AuthState {
// on page reload without a full re-login.
wrapped_dek: string | null;
wrapped_dek_iv: string | null;
// Account X25519 identity keypair (Phase A1). The public key is plaintext;
// the private key is the DEK-wrapped ciphertext blob. Persisted for the same
// reason as the wrapped DEK — the unlock screen unwraps it into memory.
identity_public_key: string | null;
identity_private_key_wrapped: string | null;
identity_private_key_wrapped_iv: string | null;
// Actions
login: (email: string, password: string) => Promise<void>;
@ -128,6 +139,9 @@ export const useAuthStore = create<AuthState>()(
error: null,
wrapped_dek: null,
wrapped_dek_iv: null,
identity_public_key: null,
identity_private_key_wrapped: null,
identity_private_key_wrapped_iv: null,
login: async (email: string, password: string) => {
set({ isLoading: true, error: null });
@ -144,6 +158,26 @@ export const useAuthStore = create<AuthState>()(
iv: response.wrapped_dek_iv,
});
setEncKey(dek);
// Once the DEK is available, also unwrap the X25519 identity
// private key (Phase A1) into in-memory storage.
if (
response.identity_private_key_wrapped &&
response.identity_private_key_wrapped_iv
) {
try {
const identityPrivate = await unwrapIdentityPrivateKey(
{
data: response.identity_private_key_wrapped,
iv: response.identity_private_key_wrapped_iv,
},
dek,
);
setIdentityPrivate(identityPrivate);
} catch {
// Wrapped private key present but failed to unwrap —
// non-fatal; Phase B features will surface a re-setup need.
}
}
} catch {
// Fallback to the PBKDF2-derived key (Phase 1 compat).
}
@ -160,6 +194,9 @@ export const useAuthStore = create<AuthState>()(
isLoading: false,
wrapped_dek: response.wrapped_dek ?? null,
wrapped_dek_iv: response.wrapped_dek_iv ?? null,
identity_public_key: response.identity_public_key ?? null,
identity_private_key_wrapped: response.identity_private_key_wrapped ?? null,
identity_private_key_wrapped_iv: response.identity_private_key_wrapped_iv ?? null,
});
} catch (error: any) {
clearEncKey();
@ -181,6 +218,13 @@ export const useAuthStore = create<AuthState>()(
const setup = await setupEncryption(password, recoveryPhrase);
setEncKey(setup.dek);
// Phase A1: generate the account X25519 identity keypair and wrap
// the private half under the account DEK. The public key is sent
// plaintext; the wrapped private key is opaque ciphertext.
const { publicKey, privateKey } = await generateIdentityKeyPair();
const wrappedPrivate = await wrapIdentityPrivateKey(privateKey, setup.dek);
setIdentityPrivate(privateKey);
const response = await apiService.register({
username,
email,
@ -190,7 +234,10 @@ export const useAuthStore = create<AuthState>()(
recovery_wrapped_dek: setup.recoveryWrappedDek?.data,
recovery_wrapped_dek_iv: setup.recoveryWrappedDek?.iv,
recovery_phrase: setup.recoveryKekHash,
} as any);
identity_public_key: publicKey,
identity_private_key_wrapped: wrappedPrivate.data,
identity_private_key_wrapped_iv: wrappedPrivate.iv,
});
set({
user: {
user_id: response.user_id,
@ -203,6 +250,9 @@ export const useAuthStore = create<AuthState>()(
isLoading: false,
wrapped_dek: setup.passwordWrappedDek.data,
wrapped_dek_iv: setup.passwordWrappedDek.iv,
identity_public_key: publicKey,
identity_private_key_wrapped: wrappedPrivate.data,
identity_private_key_wrapped_iv: wrappedPrivate.iv,
});
} catch (error: any) {
set({
@ -254,6 +304,7 @@ export const useAuthStore = create<AuthState>()(
logout: async () => {
clearEncKey();
clearIdentityPrivate();
await apiService.logout();
set({
user: null,
@ -262,6 +313,9 @@ export const useAuthStore = create<AuthState>()(
error: null,
wrapped_dek: null,
wrapped_dek_iv: null,
identity_public_key: null,
identity_private_key_wrapped: null,
identity_private_key_wrapped_iv: null,
});
},
@ -296,6 +350,9 @@ export const useAuthStore = create<AuthState>()(
isAuthenticated: state.isAuthenticated,
wrapped_dek: state.wrapped_dek,
wrapped_dek_iv: state.wrapped_dek_iv,
identity_public_key: state.identity_public_key,
identity_private_key_wrapped: state.identity_private_key_wrapped,
identity_private_key_wrapped_iv: state.identity_private_key_wrapped_iv,
}),
}
)

View file

@ -42,6 +42,11 @@ export interface AuthTokens {
email?: string;
wrapped_dek?: string;
wrapped_dek_iv?: string;
/** Account X25519 identity keypair (Phase A1). Public key is plaintext;
* private key is wrapped under the account DEK. Absent for legacy accounts. */
identity_public_key?: string;
identity_private_key_wrapped?: string;
identity_private_key_wrapped_iv?: string;
}
export interface LoginRequest {
@ -54,6 +59,18 @@ export interface RegisterRequest {
email: string;
password: string;
role?: 'patient' | 'provider' | 'admin';
/** Zero-knowledge wrapped DEK (password KEK). */
wrapped_dek?: string;
wrapped_dek_iv?: string;
/** Zero-knowledge wrapped DEK (recovery KEK). */
recovery_wrapped_dek?: string;
recovery_wrapped_dek_iv?: string;
/** Recovery proof (PBKDF2 derivation of the recovery phrase). */
recovery_phrase?: string;
/** Account X25519 identity keypair (Phase A1). */
identity_public_key?: string;
identity_private_key_wrapped?: string;
identity_private_key_wrapped_iv?: string;
}
// Medication Types