feat(eddsa-poseidon)!: make EdDSAPoseidon return bigints not strings

BREAKING CHANGE: Return type changes will require users to update their code.

re Fixes privacy-scaling-explorations#199

packages/circuits/package.json

@@ -22,9 +22,9 @@
     },
     "devDependencies": {
         "@types/mocha": "^10.0.6",
-        "@zk-kit/baby-jubjub": "0.1.1",
-        "@zk-kit/eddsa-poseidon": "0.5.1",
-        "@zk-kit/poseidon-cipher": "0.1.1",
+        "@zk-kit/baby-jubjub": "0.3.0",
+        "@zk-kit/eddsa-poseidon": "0.9.0",
+        "@zk-kit/poseidon-cipher": "0.3.0",
         "@zk-kit/smt": "1.0.0",
         "@zk-kit/utils": "0.8.0",
         "circomkit": "0.0.24",

packages/circuits/tests/common.ts

@@ -38,11 +38,7 @@ export const circomkit = new Circomkit({
  * @param privateKey the private key to generate a public key from
  * @returns the public key
  */
-export const genPublicKey = (privateKey: bigint): [bigint, bigint] => {
-    const key = derivePublicKey(privateKey)
-
-    return key.map((x: string) => BigInt(x)) as [bigint, bigint]
-}
+export const genPublicKey = (privateKey: bigint): [bigint, bigint] => derivePublicKey(privateKey)
 
 /**
  * Generates an Elliptic-Curve Diffie–Hellman (ECDH) shared key given a private
@@ -54,7 +50,7 @@ export const genPublicKey = (privateKey: bigint): [bigint, bigint] => {
 export const genEcdhSharedKey = (privKey: bigint, pubKey: [bigint, bigint]): Point<bigint> => {
     const secretScalar = deriveSecretScalar(privKey)
 
-    return mulPointEscalar(pubKey, BigInt(secretScalar)) as Point<bigint>
+    return mulPointEscalar(pubKey, secretScalar) as Point<bigint>
 }
 
 /**

packages/circuits/tests/ecdh.test.ts

@@ -25,7 +25,7 @@ describe("ECDH Shared Key derivation circuit", () => {
         const ecdhSharedKey = genEcdhSharedKey(bgPrivateKey1, publicKey2)
 
         const circuitInputs = {
-            privateKey: BigInt(deriveSecretScalar(bgPrivateKey1)),
+            privateKey: deriveSecretScalar(bgPrivateKey1),
             publicKey: publicKey2
         }
 
@@ -45,12 +45,12 @@ describe("ECDH Shared Key derivation circuit", () => {
         const ecdhSharedKey2 = genEcdhSharedKey(bgPrivateKey2, publicKey1)
 
         const circuitInputs = {
-            privateKey: BigInt(deriveSecretScalar(bgPrivateKey1)),
+            privateKey: deriveSecretScalar(bgPrivateKey1),
             publicKey: publicKey2
         }
 
         const circuitInputs2 = {
-            privateKey: BigInt(deriveSecretScalar(bgPrivateKey2)),
+            privateKey: deriveSecretScalar(bgPrivateKey2),
             publicKey: publicKey1
         }
 
@@ -65,7 +65,7 @@ describe("ECDH Shared Key derivation circuit", () => {
     })
 
     it("should generate the same ECDH key consistently for the same inputs", async () => {
-        const privateKey1 = BigInt(deriveSecretScalar(Buffer.from(crypto.getRandomValues(32))))
+        const privateKey1 = deriveSecretScalar(Buffer.from(crypto.getRandomValues(32)))
         const privateKey2 = crypto.getRandomValues(32)
         const publicKey2 = genPublicKey(beBufferToBigInt(Buffer.from(privateKey2)))
 

packages/circuits/tests/eddsa-proof.test.ts

@@ -13,7 +13,7 @@ describe("eddsa-proof", () => {
     const commitment = poseidon2(publicKey)
 
     const INPUT = {
-        secret: BigInt(deriveSecretScalar(secret)),
+        secret: deriveSecretScalar(secret),
         scope
     }
 

packages/eddsa-poseidon/README.md

@@ -112,8 +112,8 @@ const publicKey = derivePublicKey(privateKey)
 
 /*
 [
-    '17191193026255111087474416516591393721975640005415762645730433950079177536248',
-    '13751717961795090314625781035919035073474308127816403910435238282697898234143'
+    17191193026255111087474416516591393721975640005415762645730433950079177536248,
+    13751717961795090314625781035919035073474308127816403910435238282697898234143
 ]
 */
 console.log(publicKey)
@@ -124,10 +124,10 @@ const signature = signMessage(privateKey, message)
 /*
 {    
     R8: [
-        '12949573675545142400102669657964360005184873166024880859462384824349649539693',
-        '18253636630408169174294927826710424418689461166073329946402765380454102840608'
+        12949573675545142400102669657964360005184873166024880859462384824349649539693,
+        18253636630408169174294927826710424418689461166073329946402765380454102840608
     ],
-    S: '701803947557694254685424075312408605924670918868054593580245088593184746870'
+    S: 701803947557694254685424075312408605924670918868054593580245088593184746870
 }
 */
 console.log(signature)
@@ -157,8 +157,8 @@ const unpackedPublicKey = unpackPublicKey(packedPublicKey)
 
 /*
 [
-    '17191193026255111087474416516591393721975640005415762645730433950079177536248',
-    '13751717961795090314625781035919035073474308127816403910435238282697898234143'
+    17191193026255111087474416516591393721975640005415762645730433950079177536248,
+    13751717961795090314625781035919035073474308127816403910435238282697898234143
 ]
 */
 console.log(unpackedPublicKey)

packages/eddsa-poseidon/src/eddsa-poseidon.ts

@@ -31,7 +31,7 @@ import { hash as blake, checkMessage, checkPrivateKey, isPoint, isSignature, pru
  * @param privateKey The EdDSA private key for generating the associated public key.
  * @returns The derived secret scalar to be used to calculate public key and optimized for circuit calculations.
  */
-export function deriveSecretScalar(privateKey: BigNumberish): string {
+export function deriveSecretScalar(privateKey: BigNumberish): bigint {
     // Convert the private key to buffer.
     privateKey = checkPrivateKey(privateKey)
 
@@ -40,7 +40,7 @@ export function deriveSecretScalar(privateKey: BigNumberish): string {
     hash = hash.slice(0, 32)
     hash = pruneBuffer(hash)
 
-    return scalar.shiftRight(leBufferToBigInt(hash), BigInt(3)).toString()
+    return scalar.shiftRight(leBufferToBigInt(hash), BigInt(3))
 }
 
 /**
@@ -52,13 +52,13 @@ export function deriveSecretScalar(privateKey: BigNumberish): string {
  * @param privateKey The private key used for generating the public key.
  * @returns The derived public key.
  */
-export function derivePublicKey(privateKey: BigNumberish): Point<string> {
+export function derivePublicKey(privateKey: BigNumberish): Point<bigint> {
     const s = deriveSecretScalar(privateKey)
 
-    const publicKey = mulPointEscalar(Base8, BigInt(s))
+    const publicKey = mulPointEscalar(Base8, s)
 
     // Convert the public key values to strings so that it can easily be exported as a JSON.
-    return [publicKey[0].toString(), publicKey[1].toString()]
+    return [publicKey[0], publicKey[1]]
 }
 
 /**
@@ -68,7 +68,7 @@ export function derivePublicKey(privateKey: BigNumberish): Point<string> {
  * @param message The message to be signed.
  * @returns The signature object, containing properties relevant to EdDSA signatures, such as 'R8' and 'S' values.
  */
-export function signMessage(privateKey: BigNumberish, message: BigNumberish): Signature<string> {
+export function signMessage(privateKey: BigNumberish, message: BigNumberish): Signature<bigint> {
     // Convert the private key to buffer.
     privateKey = checkPrivateKey(privateKey)
 
@@ -93,10 +93,7 @@ export function signMessage(privateKey: BigNumberish, message: BigNumberish): Si
     const S = Fr.add(r, Fr.mul(hm, s))
 
     // Convert the signature values to strings so that it can easily be exported as a JSON.
-    return {
-        R8: [R8[0].toString(), R8[1].toString()],
-        S: S.toString()
-    }
+    return { R8, S }
 }
 
 /**
@@ -145,15 +142,15 @@ export function verifySignature(message: BigNumberish, signature: Signature, pub
  * @param publicKey The public key to be packed.
  * @returns A string representation of the packed public key.
  */
-export function packPublicKey(publicKey: Point): string {
+export function packPublicKey(publicKey: Point): bigint {
     if (!isPoint(publicKey) || !inCurve(publicKey)) {
         throw new Error("Invalid public key")
     }
 
     // Convert the public key values to big integers for calculations.
     const _publicKey: Point<bigint> = [BigInt(publicKey[0]), BigInt(publicKey[1])]
 
-    return packPoint(_publicKey).toString()
+    return packPoint(_publicKey)
 }
 
 /**
@@ -162,7 +159,7 @@ export function packPublicKey(publicKey: Point): string {
  * @param publicKey The packed public key as a bignumberish.
  * @returns The unpacked public key as a point.
  */
-export function unpackPublicKey(publicKey: BigNumberish): Point<string> {
+export function unpackPublicKey(publicKey: BigNumberish): Point<bigint> {
     requireBigNumberish(publicKey, "publicKey")
 
     const unpackedPublicKey = unpackPoint(bigNumberishToBigInt(publicKey))
@@ -171,7 +168,7 @@ export function unpackPublicKey(publicKey: BigNumberish): Point<string> {
         throw new Error("Invalid public key")
     }
 
-    return [unpackedPublicKey[0].toString(), unpackedPublicKey[1].toString()]
+    return [unpackedPublicKey[0], unpackedPublicKey[1]]
 }
 
 /**
@@ -210,7 +207,7 @@ export function packSignature(signature: Signature): Buffer {
  * @param packedSignature the 64 byte buffer to unpack
  * @returns a Signature with numbers in string form
  */
-export function unpackSignature(packedSignature: Buffer): Signature<string> {
+export function unpackSignature(packedSignature: Buffer): Signature<bigint> {
     requireBuffer(packedSignature, "packedSignature")
     if (packedSignature.length !== 64) {
         throw new Error("Packed signature must be 64 bytes")
@@ -223,8 +220,8 @@ export function unpackSignature(packedSignature: Buffer): Signature<string> {
         throw new Error(`Invalid packed signature point ${sliceS.toString("hex")}.`)
     }
     return {
-        R8: [unpackedR8[0].toString(), unpackedR8[1].toString()],
-        S: leBufferToBigInt(sliceS).toString()
+        R8: [unpackedR8[0], unpackedR8[1]],
+        S: leBufferToBigInt(sliceS)
     }
 }
 
@@ -236,11 +233,11 @@ export class EdDSAPoseidon {
     // Private key for signing, stored securely.
     privateKey: BigNumberish
     // The secret scalar derived from the private key to compute the public key.
-    secretScalar: string
+    secretScalar: bigint
     // The public key corresponding to the private key.
-    publicKey: Point
+    publicKey: Point<bigint>
     // A packed (compressed) representation of the public key for efficient operations.
-    packedPublicKey: string
+    packedPublicKey: bigint
 
     /**
      * Initializes a new instance, deriving necessary cryptographic parameters from the provided private key.
@@ -251,15 +248,15 @@ export class EdDSAPoseidon {
         this.privateKey = privateKey
         this.secretScalar = deriveSecretScalar(privateKey)
         this.publicKey = derivePublicKey(privateKey)
-        this.packedPublicKey = packPublicKey(this.publicKey) as string
+        this.packedPublicKey = packPublicKey(this.publicKey)
     }
 
     /**
      * Signs a given message using the private key and returns the signature.
      * @param message The message to be signed.
      * @returns The signature of the message.
      */
-    signMessage(message: BigNumberish): Signature<string> {
+    signMessage(message: BigNumberish): Signature<bigint> {
         return signMessage(this.privateKey, message)
     }