From 19a0d85afd08cdd8533ed814a9664c7509fb8d9b Mon Sep 17 00:00:00 2001 From: Niels Andriesse Date: Mon, 6 May 2019 11:32:11 +1000 Subject: [PATCH] Implement public key checking logic --- SignalServiceKit/src/Loki/ECKeyPair.swift | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/SignalServiceKit/src/Loki/ECKeyPair.swift b/SignalServiceKit/src/Loki/ECKeyPair.swift index a90c81f8f..ceb59196f 100644 --- a/SignalServiceKit/src/Loki/ECKeyPair.swift +++ b/SignalServiceKit/src/Loki/ECKeyPair.swift @@ -9,4 +9,14 @@ public extension ECKeyPair { // Prefixing with "05" is necessary for what seems to be a sort of Signal public key versioning system return "05" + publicKey.map { String(format: "%02hhx", $0) }.joined() } + + static func isValidHexEncodedPublicKey(candidate: String) -> Bool { + // Check that it's a valid hexadecimal encoding + let allowedCharacters = CharacterSet(charactersIn: "0123456789ABCDEF") + guard candidate.uppercased().unicodeScalars.allSatisfy({ allowedCharacters.contains($0) }) else { return false } + // Check that it has either length 33 and a leading "05" or length 32 + guard (candidate.count == 33 && candidate.hasPrefix("05")) || candidate.count == 32 else { return false } + // It appears to be a valid public key + return true + } }