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fix(identity)!: update type of private key (#803)
* fix(identity)!: update type of private key The new types support buffers and text, so that there is less ambiguity on strings. * refactor(identity): use base64 as encoding for exported priv keys re #799 * Update packages/identity/src/index.ts Co-authored-by: Andrew Twyman <artwyman@users.noreply.github.com> * test(identity): add more tests re #799 --------- Co-authored-by: Andrew Twyman <artwyman@users.noreply.github.com>
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‎packages/identity/README.md‎

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@@ -84,6 +84,28 @@ const { privateKey, publicKey, commitment } = new Identity()
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const identity = new Identity("your-private-key")
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```
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\# **identity.export**(): _string_
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```typescript
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import { Identity } from "@semaphore-protocol/identity"
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const identity = new Identity()
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const privateKey = identity.export()
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```
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\# **identity.import**(privateKey: _string_): _Identity_
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```typescript
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import { Identity } from "@semaphore-protocol/identity"
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const identity = new Identity()
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const privateKey = identity.export()
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const identity2 = Identity.import(privateKey)
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```
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\# **identity.signMessage**(message: _BigNumberish_): _Signature\<string>_
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```typescript

‎packages/identity/package.json‎

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@@ -40,8 +40,8 @@
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},
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"dependencies": {
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"@zk-kit/baby-jubjub": "1.0.1",
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"@zk-kit/eddsa-poseidon": "1.0.1",
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"@zk-kit/utils": "1.0.0",
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"@zk-kit/eddsa-poseidon": "1.0.2",
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"@zk-kit/utils": "1.2.0",
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"poseidon-lite": "0.2.0"
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}
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}

‎packages/identity/src/index.ts‎

Lines changed: 34 additions & 34 deletions
Original file line numberDiff line numberDiff line change
@@ -1,9 +1,8 @@
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import type { Point } from "@zk-kit/baby-jubjub"
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import { EdDSAPoseidon, Signature, signMessage, verifySignature } from "@zk-kit/eddsa-poseidon"
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import type { BigNumberish } from "@zk-kit/utils"
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import { hexadecimalToBuffer } from "@zk-kit/utils/conversions"
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import { requireString } from "@zk-kit/utils/error-handlers"
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import { isHexadecimal } from "@zk-kit/utils/type-checks"
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import { base64ToBuffer, bufferToBase64, textToBase64 } from "@zk-kit/utils/conversions"
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import { isString } from "@zk-kit/utils/type-checks"
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import { poseidon2 } from "poseidon-lite/poseidon2"
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/**
@@ -13,12 +12,11 @@ import { poseidon2 } from "poseidon-lite/poseidon2"
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* and {@link https://www.poseidon-hash.info | Poseidon} for signatures.
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* In addition, the commitment, i.e. the hash of the public key, is used to represent
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* Semaphore identities in groups, adding an additional layer of privacy and security.
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* The private key of the identity is stored as a hexadecimal string or text.
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* The other attributes are stored as stringified bigint.
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* The private key of the identity can be exported as a base64 string.
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*/
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export class Identity {
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// The EdDSA private key, passed as a parameter or generated randomly.
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private _privateKey: string
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private _privateKey: string | Buffer | Uint8Array
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// The secret scalar derived from the private key.
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// It is used in circuits to derive the public key.
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private _secretScalar: bigint
@@ -28,9 +26,8 @@ export class Identity {
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private _commitment: bigint
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/**
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* Initializes the class attributes based on a given private key, which must be a hexadecimal string or a text.
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* Hexadecimal strings must not start with '0x' or '0X'.
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* If the private key is not passed as a parameter, a random hexadecimal key will be generated.
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* Initializes the class attributes based on a given private key, which must be text or a buffer.
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* If the private key is not passed as a parameter, a random private key will be generated.
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* The EdDSAPoseidon class is used to generate the secret scalar and the public key.
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* Additionally, the constructor computes a commitment of the public key using a hash function (Poseidon).
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*
@@ -43,35 +40,20 @@ export class Identity {
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*
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* @param privateKey The private key used to derive the public key (hexadecimal or string).
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*/
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constructor(privateKey?: string) {
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let eddsa: EdDSAPoseidon
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if (privateKey) {
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requireString(privateKey, "privateKey")
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this._privateKey = privateKey
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if (isHexadecimal(privateKey, false)) {
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eddsa = new EdDSAPoseidon(hexadecimalToBuffer(privateKey))
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} else {
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eddsa = new EdDSAPoseidon(privateKey)
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}
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} else {
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eddsa = new EdDSAPoseidon()
61-
62-
this._privateKey = eddsa.privateKey as string
63-
}
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constructor(privateKey?: string | Buffer | Uint8Array) {
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const eddsa = new EdDSAPoseidon(privateKey)
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this._privateKey = eddsa.privateKey
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this._secretScalar = eddsa.secretScalar
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this._publicKey = eddsa.publicKey
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this._commitment = poseidon2(this._publicKey)
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}
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/**
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* Returns the private key.
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* @returns The private key as a string (hexadecimal or text).
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* @returns The private key as a buffer or text.
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*/
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public get privateKey(): string {
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public get privateKey(): string | Buffer | Uint8Array {
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return this._privateKey
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}
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@@ -99,6 +81,28 @@ export class Identity {
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return this._commitment
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}
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/**
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* Returns the private key encoded as a base64 string.
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* @returns The private key as a base64 string.
87+
*/
88+
public export(): string {
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if (isString(this._privateKey)) {
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return textToBase64(this._privateKey as string)
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}
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return bufferToBase64(this.privateKey as Buffer | Uint8Array)
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}
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/**
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* Returns a Semaphore identity based on a private key encoded as a base64 string.
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* The private key will be converted to a buffer, regardless of its original type.
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* @param privateKey The private key as a base64 string.
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* @returns The Semaphore identity.
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*/
102+
static import(privateKey: string): Identity {
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return new Identity(base64ToBuffer(privateKey))
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}
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/**
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* Generates a signature for a given message using the private key.
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* This method demonstrates how to sign a message and could be used
@@ -112,11 +116,7 @@ export class Identity {
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* @returns A {@link https://zkkit.pse.dev/types/_zk_kit_eddsa_poseidon.Signature.html | Signature} object containing the signature components.
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*/
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public signMessage(message: BigNumberish): Signature<bigint> {
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const privateKey = isHexadecimal(this.privateKey, false)
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? hexadecimalToBuffer(this.privateKey)
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: this.privateKey
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return signMessage(privateKey, message)
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return signMessage(this.privateKey, message)
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}
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/**

‎packages/identity/tests/index.test.ts‎

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Original file line numberDiff line numberDiff line change
@@ -1,43 +1,111 @@
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import { derivePublicKey, deriveSecretScalar } from "@zk-kit/eddsa-poseidon"
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import { poseidon2 } from "poseidon-lite"
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import { Identity } from "../src"
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describe("Identity", () => {
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const privateKeyText = "secret"
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const privateKeyHexadecimal = "dd998334940df8931b76d899fdb189415f7ff4280599f03a7574725a166aad7d"
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const privateKeyBuffer = Buffer.from("another secret")
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describe("# Identity", () => {
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it("Should create an identity with a random secret (private key)", () => {
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const identity = new Identity()
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const privateKey = Buffer.from(identity.privateKey)
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11-
expect(typeof identity.privateKey).toBe("string")
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expect(identity.privateKey).toHaveLength(64)
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expect(typeof identity.secretScalar).toBe("bigint")
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expect(identity.publicKey).toHaveLength(2)
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expect(typeof identity.commitment).toBe("bigint")
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expect(identity.privateKey).toHaveLength(32)
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expect(identity.secretScalar).toBe(deriveSecretScalar(privateKey))
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expect(identity.publicKey).toStrictEqual(derivePublicKey(privateKey))
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expect(identity.commitment).toBe(poseidon2(identity.publicKey))
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})
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it("Should create deterministic identities from a secret text (private key)", () => {
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it("Should create a deterministic identity from a secret text (private key)", () => {
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const identity = new Identity(privateKeyText)
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21-
expect(typeof identity.privateKey).toBe("string")
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expect(typeof identity.secretScalar).toBe("bigint")
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expect(identity.publicKey).toHaveLength(2)
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expect(typeof identity.commitment).toBe("bigint")
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expect(identity.secretScalar).toBe(deriveSecretScalar(privateKeyText))
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expect(identity.publicKey).toStrictEqual(derivePublicKey(privateKeyText))
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expect(identity.commitment).toBe(poseidon2(identity.publicKey))
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})
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27-
it("Should create deterministic identities from a secret hexadecimal (private key)", () => {
28-
const identity = new Identity(privateKeyHexadecimal)
28+
it("Should create a deterministic identity from a secret buffer (private key)", () => {
29+
const identity = new Identity(privateKeyBuffer)
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30-
expect(typeof identity.privateKey).toBe("string")
31-
expect(identity.privateKey).toHaveLength(64)
32-
expect(typeof identity.secretScalar).toBe("bigint")
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expect(identity.publicKey).toHaveLength(2)
34-
expect(typeof identity.commitment).toBe("bigint")
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expect(identity.secretScalar).toBe(deriveSecretScalar(privateKeyBuffer))
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expect(identity.publicKey).toStrictEqual(derivePublicKey(privateKeyBuffer))
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expect(identity.commitment).toBe(poseidon2(identity.publicKey))
34+
})
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36+
it("Should create the same identity if the private key is the same", () => {
37+
const identity = new Identity()
38+
39+
const identity2 = new Identity(identity.privateKey)
40+
41+
expect(identity.privateKey).toStrictEqual(identity2.privateKey)
42+
expect(identity.secretScalar).toBe(identity2.secretScalar)
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expect(identity.publicKey).toStrictEqual(identity2.publicKey)
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expect(identity.commitment).toBe(identity2.commitment)
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})
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3747
it("Should throw an error if the private key is not a string", () => {
3848
const fun = () => new Identity(32 as any)
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40-
expect(fun).toThrow("Parameter 'privateKey' is not a string, received type: number")
50+
expect(fun).toThrow("Parameter 'privateKey' is none of the following types: Buffer, Uint8Array, string")
51+
})
52+
})
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54+
describe("# export", () => {
55+
it("Should export an identity where the private key is a buffer", () => {
56+
const identity = new Identity(privateKeyBuffer)
57+
58+
const privateKey = identity.export()
59+
60+
expect(typeof privateKey).toBe("string")
61+
expect(Buffer.from(privateKey, "base64")).toStrictEqual(privateKeyBuffer)
62+
})
63+
64+
it("Should export an identity where the private key is text", () => {
65+
const identity = new Identity(privateKeyBuffer)
66+
67+
const privateKey = identity.export()
68+
69+
expect(typeof privateKey).toBe("string")
70+
expect(Buffer.from(privateKey, "base64")).toStrictEqual(privateKeyBuffer)
71+
})
72+
})
73+
74+
describe("# import", () => {
75+
it("Should import an identity with a private key of buffer type", () => {
76+
const identity = new Identity(privateKeyBuffer)
77+
const privateKey = identity.export()
78+
79+
const identity2 = Identity.import(privateKey)
80+
81+
expect(identity2.privateKey).toStrictEqual(identity.privateKey)
82+
expect(identity2.secretScalar).toBe(identity.secretScalar)
83+
expect(identity2.publicKey).toStrictEqual(identity.publicKey)
84+
expect(identity2.commitment).toBe(identity.commitment)
85+
})
86+
87+
it("Should import an identity with a private key of text type", () => {
88+
const identity = new Identity(privateKeyText)
89+
const privateKey = identity.export()
90+
91+
const identity2 = Identity.import(privateKey)
92+
93+
expect(identity2.privateKey).toStrictEqual(Buffer.from(identity.privateKey))
94+
expect(identity2.secretScalar).toBe(identity.secretScalar)
95+
expect(identity2.publicKey).toStrictEqual(identity.publicKey)
96+
expect(identity2.commitment).toBe(identity.commitment)
97+
})
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99+
it("Should import an identity generated from a random private key", () => {
100+
const identity = new Identity()
101+
const privateKey = identity.export()
102+
103+
const identity2 = Identity.import(privateKey)
104+
105+
expect(identity2.privateKey).toStrictEqual(Buffer.from(identity.privateKey))
106+
expect(identity2.secretScalar).toBe(identity.secretScalar)
107+
expect(identity2.publicKey).toStrictEqual(identity.publicKey)
108+
expect(identity2.commitment).toBe(identity.commitment)
41109
})
42110
})
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@@ -63,7 +131,7 @@ describe("Identity", () => {
63131
})
64132

65133
it("Should verify a signature with hexadecimal private key", () => {
66-
const identity = new Identity(privateKeyHexadecimal)
134+
const identity = new Identity(privateKeyBuffer)
67135

68136
const signature = identity.signMessage("message")
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‎yarn.lock‎

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"@rollup/plugin-node-resolve": "npm:^15.2.3"
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"@rollup/plugin-typescript": "npm:^11.1.6"
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"@zk-kit/baby-jubjub": "npm:1.0.1"
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"@zk-kit/eddsa-poseidon": "npm:1.0.1"
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"@zk-kit/utils": "npm:1.0.0"
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"@zk-kit/eddsa-poseidon": "npm:1.0.2"
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"@zk-kit/utils": "npm:1.2.0"
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poseidon-lite: "npm:0.2.0"
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rimraf: "npm:^5.0.5"
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rollup: "npm:^4.12.0"
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languageName: node
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linkType: hard
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"@zk-kit/eddsa-poseidon@npm:1.0.1":
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version: 1.0.1
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resolution: "@zk-kit/eddsa-poseidon@npm:1.0.1"
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"@zk-kit/eddsa-poseidon@npm:1.0.2":
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version: 1.0.2
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resolution: "@zk-kit/eddsa-poseidon@npm:1.0.2"
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dependencies:
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"@zk-kit/baby-jubjub": "npm:1.0.1"
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"@zk-kit/utils": "npm:1.0.0"
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buffer: "npm:6.0.3"
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checksum: 10/337db4a73bd58680e462b6a82f95321406b3cffce7dce0413f7c857159798b8d85120750de5f5e4c7f2bcc102a02a5e3145302aeb9110a3b6172e6bd3bc29f43
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checksum: 10/4b4e984a96c5dbc95a8cf36ceb8b3712e37291c1473d01b0e22c15a33311e9cf88c86175d878dacda1852cc905cd2074aaa76defeaed33490be3964ca7a53372
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languageName: node
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linkType: hard
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languageName: node
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linkType: hard
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"@zk-kit/utils@npm:1.2.0":
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version: 1.2.0
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resolution: "@zk-kit/utils@npm:1.2.0"
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dependencies:
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buffer: "npm:^6.0.3"
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checksum: 10/4c0b37d64b28a6cc33c901a0c59325b1fe9c31e6519eaefe4aa6028ae9cb85e97f047976942875face030a1835d5c955ea546d7dc4fcf9d35df79192ee2502f3
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languageName: node
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linkType: hard
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"JSONStream@npm:1.3.2":
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version: 1.3.2
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resolution: "JSONStream@npm:1.3.2"

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