fix crash for String index is out of bounds

Author: karthuszY

Sources/Web3Core/EthereumAddress/EthereumAddress.swift

@@ -63,7 +63,8 @@ public struct EthereumAddress: Equatable {
     /// represented as `ASCII` data. Otherwise, checksummed address is returned with `0x` prefix.
     public static func toChecksumAddress(_ addr: String) -> String? {
         let address = addr.lowercased().stripHexPrefix()
-        guard let hash = address.data(using: .ascii)?.sha3(.keccak256).toHexString().stripHexPrefix() else { return nil }
+        guard address.count == 40,
+              let hash = address.data(using: .ascii)?.sha3(.keccak256).toHexString().stripHexPrefix() else { return nil }
         var ret = "0x"
 
         for (i, char) in address.enumerated() {

Tests/web3swiftTests/localTests/UncategorizedTests.swift

@@ -35,6 +35,12 @@ class UncategorizedTests: LocalTestCase {
         let output = EthereumAddress.toChecksumAddress(input)
         XCTAssert(output == "0xfB6916095ca1df60bB79Ce92cE3Ea74c37c5d359", "Failed to checksum address")
     }
+    
+    func testErrorAddressChecksumAddress() throws {
+        let input = "ethereum:0xfb6916095ca1df60bb79ce92ce3ea74c37c5d359?chainId=1&action=transfer"
+        let output = EthereumAddress.toChecksumAddress(input)
+        XCTAssert(output == nil, "Failed to checksum address")
+    }
 
     func testChecksumAddressParsing() throws {
         let input = "0xfB6916095ca1df60bB79Ce92cE3Ea74c37c5d359"