Merge pull request #72 from EOSIO/sm/fix/public-key-recovery

Potential fix for extracting public key from some private keys.
EOSIO · Nov 5, 2019 · 41a78a5 · 41a78a5
2 parents a5d5d31 + 3d204dd
commit 41a78a5
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Showing 2 changed files with 22 additions and 1 deletion.
diff --git a/EosioSwiftEcc/Recover/EccRecoverKey.swift b/EosioSwiftEcc/Recover/EccRecoverKey.swift
@@ -60,15 +60,22 @@ public class EccRecoverKey {
 
             let xBNstr = BN_bn2hex(xBN)!
             let yBNstr = BN_bn2hex(yBN)!
+
             let xHex = String(cString: xBNstr)
+            let xPad = max(64, xHex.count)
+            let xHexPadded = String(repeatElement("0", count: xPad - xHex.count) + xHex)
+
             let yHex = String(cString: yBNstr)
+            let yPad = max(64, yHex.count)
+            let yHexPadded = String(repeatElement("0", count: yPad - yHex.count) + yHex)
+
             CRYPTO_free(xBNstr)
             CRYPTO_free(yBNstr)
 
             BN_free(xBN)
             BN_free(yBN)
             EC_POINT_free(pubKeyPoint)
-            recoveredPubKeyHex = "04" + xHex + yHex
+            recoveredPubKeyHex = "04" + xHexPadded + yHexPadded
         }
         EC_GROUP_free(group)
         BN_CTX_free(ctx)

diff --git a/EosioSwiftEccTests/EosioSwiftEccRecoverKeyTests.swift b/EosioSwiftEccTests/EosioSwiftEccRecoverKeyTests.swift
@@ -78,6 +78,20 @@ class EosioSwiftEccRecoverKeyTests: XCTestCase {
 
     }
 
+    func test_eosioK1_private_to_public_needs_padding() {
+        do {
+            let privateKey = "5KLuCa3aEXW2kLyj2xbHjn9fsoZmmBNBTbVHhnkzVXtgjipDyQF"
+            let publicKey =  try EccRecoverKey.recoverPublicKey(privateKey: Data(eosioPrivateKey: privateKey), curve: .k1)
+            guard let eosLegacyPublicKey = publicKey.toCompressedPublicKey?.toEosioLegacyPublicKey else {
+                XCTFail("Should not fail to convert to EOSIO Legacy Public key.")
+                return
+            }
+            XCTAssert(eosLegacyPublicKey == "EOS7mbBaD7UFLQKVE3oGkAp4ToFaFjaedjJA2WBpTBY8yXgnwK53e")
+        } catch let error {
+            XCTFail("Should not error extracting public from private key: \(error.localizedDescription)")
+        }
+    }
+
     func test_eosioK1_private_to_public() {
         do {
             let privateKey = try Data(eosioPrivateKey: privateKeyK1)