fix(eddsa-poseidon): handles the negative case

privacy-scaling-explorations · Oct 25, 2024 · 5ea90de · 5ea90de
1 parent 8e67348
commit 5ea90de
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Showing 2 changed files with 12 additions and 3 deletions.
diff --git a/packages/eddsa-poseidon/src/utils.ts b/packages/eddsa-poseidon/src/utils.ts
@@ -70,8 +70,9 @@ export function checkMessage(message: BigNumberish): bigint {
         ? bigNumberishToBigInt(message)
         : bufferToBigInt(Buffer.from(message as string))
 
-    const maxLength = 2n ** 256n / 2n - 1n
-    if (bigIntMessage > maxLength) throw new Error(`Message length is larger than 32 bytes`)
+    const maxLength = 2n ** 256n / 2n
+    if (bigIntMessage < maxLength * -1n || bigIntMessage >= maxLength)
+        throw new Error(`Message length is larger than 32 bytes`)
     return bigIntMessage
 }
 

diff --git a/packages/eddsa-poseidon/tests/eddsa-poseidon-blake1.test.ts b/packages/eddsa-poseidon/tests/eddsa-poseidon-blake1.test.ts
@@ -147,7 +147,15 @@ describe("EdDSAPoseidon", () => {
     })
 
     it("Should throw an error if the message is larger than 32 Bytes [number]", async () => {
-        const message = 2 ** 256 / 2
+        const message = 2 ** 255
+
+        const fun = () => signMessage(privateKey, message)
+
+        expect(fun).toThrow(`Message length is larger than 32 bytes`)
+    })
+
+    it("Should throw an error if the message is larger than 32 Bytes [-number]", async () => {
+        const message = -(2n ** 255n + 1n)
 
         const fun = () => signMessage(privateKey, message)