add support for ctAddress

coti-io · Sep 29, 2024 · 0183765 · 0183765
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diff --git a/README.md b/README.md
@@ -200,7 +200,21 @@ Builds input text by encrypting the plaintext and signing it.
 
 - `inputText`: An object of the form { "ciphertext": { "value": int[] }, "signature": bytes[] }
 
-### 5. `decryptUint(ciphertext: bigint, userKey: string)`
+### 5.`buildAddressInputText((plaintext: string, sender: { wallet: BaseWallet; userKey: string }, contractAddress: string, functionSelector: string)`
+
+Builds input text by encrypting the plaintext and signing it.
+**Parameters:**
+
+- `plaintext`: The plaintext string message.
+- `sender`: The sender's wallet and userKey.
+- `contractAddress`: The contract address.
+- `functionSelector`: The function signature.
+
+**Returns:**
+
+- `inputText`: An object of the form { "ciphertext": { "ct1": int, "ct2": int, "ct3": int }, "signature1": bytes, "signature2": bytes, "signature3": bytes }
+
+### 6. `decryptUint(ciphertext: bigint, userKey: string)`
 
 Decrypts a value stored in a contract using a user key.
 
@@ -213,7 +227,7 @@ Decrypts a value stored in a contract using a user key.
 
 - `result`: The decrypted value.
 
-### 6. `decryptString(ciphertext: Array<bigint>, userKey: string)`
+### 7. `decryptString(ciphertext: Array<bigint>, userKey: string)`
 
 Decrypts a value stored in a contract using a user key.
 
@@ -226,6 +240,19 @@ Decrypts a value stored in a contract using a user key.
 
 - `result`: The decrypted string.
 
+### 8. `decryptAddress(ciphertext: Array<bigint>, userKey: string)`
+
+Decrypts an address stored in a contract and encrypted using a user key.
+
+**Parameters:**
+
+- `ciphertext`: An object of the form { "ct1": int, "ct2": int, "ct3": int } where each cell holds a portion of the address encrypted
+- `userKey`: The user's AES key.
+
+**Returns:**
+
+- `result`: The decrypted address.
+
 # ether_utils.ts
 
 This TypeScript library, `ethers_utils.ts`, provides ethers functionality to interact with the COTI-v2 network. Below is

diff --git a/src/crypto_utils.ts b/src/crypto_utils.ts
@@ -1,5 +1,5 @@
 import forge from 'node-forge'
-import {BaseWallet, ethers, getBytes, SigningKey, solidityPackedKeccak256} from "ethers"
+import {BaseWallet, ethers, getAddress, getBytes, isAddress, SigningKey, solidityPackedKeccak256} from "ethers"
 
 const BLOCK_SIZE = 16 // AES block size in bytes
 const HEX_BASE = 16
@@ -189,6 +189,49 @@ export function buildStringInputText(
     return inputText
 }
 
+export function buildAddressInputText(
+    plaintext: string,
+    sender: { wallet: BaseWallet; userKey: string },
+    contractAddress: string,
+    functionSelector: string
+) {
+    if (!isAddress(plaintext)) {
+        throw new Error("Plaintext must be a valid address.")
+    }
+
+    const it1 = buildInputText(
+        BigInt("0x" + plaintext.substring(2, 18)), // bytes 1 - 8
+        sender,
+        contractAddress,
+        functionSelector
+    )
+    const it2 = buildInputText(
+        BigInt("0x" + plaintext.substring(18, 34)), // bytes 9 - 16
+        sender,
+        contractAddress,
+        functionSelector
+    )
+    const it3 = buildInputText(
+        BigInt("0x" + plaintext.substring(34, 42)), // bytes 17 - 20
+        sender,
+        contractAddress,
+        functionSelector
+    )
+
+   const inputText = {
+       ciphertext: {
+           ct1: it1.ciphertext,
+           ct2: it2.ciphertext,
+           ct3: it3.ciphertext
+       },
+       signature1: it1.signature,
+       signature2: it2.signature,
+       signature3: it3.signature
+   }
+
+   return inputText
+}
+
 export function decryptUint(ciphertext: bigint, userKey: string): bigint {
     // Convert ciphertext to Uint8Array
     let ctArray = new Uint8Array()
@@ -217,7 +260,7 @@ export function decryptString(ciphertext: { value: bigint[] }, userKey: string):
     let encodedStr = new Uint8Array()
 
     for (let i = 0; i < ciphertext.value.length; i++) {
-        const decrypted = decryptUint(BigInt(ciphertext.value[i]), userKey)
+        const decrypted = decryptUint(ciphertext.value[i], userKey)
 
         encodedStr = new Uint8Array([...encodedStr, ...encodeUint(decrypted)])
     }
@@ -229,6 +272,26 @@ export function decryptString(ciphertext: { value: bigint[] }, userKey: string):
         .replace(/\0/g, '')
 }
 
+export function decryptAddress(ciphertext: { ct1: bigint, ct2: bigint, ct3: bigint }, userKey: string): string {
+    let addr = '0x'
+
+    let decrypted: bigint
+
+    decrypted = decryptUint(ciphertext.ct1, userKey)
+
+    addr += decrypted.toString(16).padStart(16, '0') // 8 bytes is 16 characters
+
+    decrypted = decryptUint(ciphertext.ct2, userKey)
+
+    addr += decrypted.toString(16).padStart(16, '0') // 8 bytes is 16 characters
+
+    decrypted = decryptUint(ciphertext.ct3, userKey)
+
+    addr += decrypted.toString(16).padStart(8, '0') // 4 bytes is 8 characters
+
+    return getAddress(addr)
+}
+
 export function generateAesKey(): string {
     return forge.random.getBytesSync(BLOCK_SIZE)
 }

diff --git a/tests/crypto_utils.test.ts b/tests/crypto_utils.test.ts
@@ -1,9 +1,11 @@
 import { Wallet } from 'ethers'
 import {
+    buildAddressInputText,
     buildInputText,
     buildStringInputText,
     decodeUint,
     decrypt,
+    decryptAddress,
     decryptRSA,
     decryptString,
     decryptUint,
@@ -429,4 +431,67 @@ describe('crypto_utils', () => {
 
         expect(plaintext).toEqual(PLAINTEXT)
     })
+
+    test('buildAddressInputText - build input text from an arbitrary address', () => {
+        const PRIVATE_KEY = '0x526c9f9fe2fc41fb30fd0dbba1d4d76d774030166ef9f819b361046f5a5b4a34'
+        const USER_KEY = '4b0418c1543dbe70f215175bcddfac42'
+        const CONTRACT_ADDRESS = '0x0000000000000000000000000000000000000001'
+        const FUNCTION_SELECTOR = '0x11223344'
+        const PLAINTEXT = '0xc0ffee254729296a45a3885639AC7E10F9d54979'
+        const CIPHERTEXT = {
+            ct1: 57746566665648186615896636477407589926815064820721185638918731479700437094224n,
+            ct2: 57746566665648186612828207168301157696292953115220848200251829797438968713040n,
+            ct3: 57746566665648186614314868401766501073179498565984802815167605437801327120208n,
+        }
+        const SIGNATURE_1 = new Uint8Array([
+            199,  62,  88,  96,  21, 229,  59, 251, 139,  82,  97,
+             58,  80, 170, 180, 202,  33,   4, 191,   0, 243,  73,
+             80, 190, 185, 212, 218,  92,  26,  21,   3,  96,  59,
+             81,  66, 165, 248,  67, 213,  67, 121, 188, 208,  66,
+              8, 165, 133, 113,  66,  51, 103,  21, 205,  41, 101,
+            134, 212, 148, 214, 192, 229, 127, 101, 139,   0
+        ])
+        const SIGNATURE_2 = new Uint8Array([
+            183, 184, 157, 140, 192,  49, 223,  89,  22,  36, 188,
+            247,  95,  12, 106,  27, 181, 184, 177, 225, 203,  18,
+            182, 141,   9,   5, 153, 106, 205, 121, 109, 217,  17,
+             14,  15,  82,   5, 130, 182, 140,   7,  58, 227, 159,
+             79,  28,  83,  57, 192, 142,   7,  70, 253, 114,  10,
+            219, 187,   2, 117, 114,  72,   7,   4, 235,   1
+        ])
+        const SIGNATURE_3 = new Uint8Array([
+            168, 150,   6, 165,  30, 219, 206,  10, 188, 110, 127,
+            254, 247, 100, 165, 255, 205,  41, 191, 112, 101, 182,
+            138,  77, 180,  79,  23,  74,  93, 118,  75, 138,  82,
+            185, 175, 209, 115,  33, 182,  29,  60,  90, 174,  90,
+             96, 195, 196, 216,  89, 140, 155, 149, 136,  30, 181,
+             79, 217, 152,  25, 141, 175,  81, 228,  34,   0
+        ])
+
+        const {ciphertext, signature1, signature2, signature3 } = buildAddressInputText(
+            PLAINTEXT,
+            { wallet: new Wallet(PRIVATE_KEY), userKey: USER_KEY },
+            CONTRACT_ADDRESS,
+            FUNCTION_SELECTOR
+        )
+
+        expect(ciphertext).toEqual(CIPHERTEXT)
+        expect(signature1).toEqual(SIGNATURE_1)
+        expect(signature2).toEqual(SIGNATURE_2)
+        expect(signature3).toEqual(SIGNATURE_3)
+    })
+
+    test('decryptAddress - decrypt ciphertext of an arbitrary address', () => {
+        const USER_KEY = '4b0418c1543dbe70f215175bcddfac42'
+        const CIPHERTEXT = {
+            ct1: 57746566665648186615896636477407589926815064820721185638918731479700437094224n,
+            ct2: 57746566665648186612828207168301157696292953115220848200251829797438968713040n,
+            ct3: 57746566665648186614314868401766501073179498565984802815167605437801327120208n,
+        }
+        const PLAINTEXT = '0xc0ffee254729296a45a3885639AC7E10F9d54979'
+
+        const plaintext = decryptAddress(CIPHERTEXT, USER_KEY)
+
+        expect(plaintext).toEqual(PLAINTEXT)
+    })
 })