Merge #15368: Descriptor checksums

fd637be8d21a606e98c037b40b268c4a1fae2244 Add checksums to descriptors.md (Pieter Wuille)
be62903c417293f6217e124669e62fd2172a18f1 Make descriptor checksums mandatory in deriveaddresses and importmulti (Pieter Wuille)
b52cb6368869c9f6dd2cd8f309b3000de514d439 Add getdescriptorinfo to compute checksum (Pieter Wuille)
3b40bff9880e9ae2817136b7d14989afccfc1937 Descriptor checksum (Pieter Wuille)

Pull request description:

  This adds support for a descriptor-specific 8-character checksum.

  Descriptors may optionally be suffixed with a `#` plus these 8 checksum characters. Any descriptor that contains a `#` at the end must be followed by a valid checksum. If the `#` is missing entirely, it is valid without checksum.

  All RPCs are updated to report descriptors that include the checksum. On input, they are optional except in `deriveaddress` and `importmulti`, which require descriptors which include a checksum.

  A new RPC is also added to analyse descriptors (`getdescriptorinfo`), which can be used to compute the checksum for a descriptor without.

Tree-SHA512: a8294b09155eb6c67fbc178b5e2d3fbc0e9bec8b6de57a13f8835550d51c2cb32a428b3c9a188ded42b454d594e9305edbd4797906b755de77a8f33c79165f6b

1 files changed, 28 insertions, 6 deletions

diff --git a/src/test/descriptor_tests.cpp b/src/test/descriptor_tests.cpp
index 8da8cfc00c..ff2b8d4fc9 100644
--- a/src/test/descriptor_tests.cpp
+++ b/src/test/descriptor_tests.cpp
@@ -18,8 +18,8 @@ void CheckUnparsable(const std::string& prv, const std::string& pub)
     FlatSigningProvider keys_priv, keys_pub;
     auto parse_priv = Parse(prv, keys_priv);
     auto parse_pub = Parse(pub, keys_pub);
-    BOOST_CHECK(!parse_priv);
-    BOOST_CHECK(!parse_pub);
+    BOOST_CHECK_MESSAGE(!parse_priv, prv);
+    BOOST_CHECK_MESSAGE(!parse_pub, pub);
 }
 
 constexpr int DEFAULT = 0;
@@ -28,6 +28,18 @@ constexpr int HARDENED = 2; // Derivation needs access to private keys
 constexpr int UNSOLVABLE = 4; // This descriptor is not expected to be solvable
 constexpr int SIGNABLE = 8; // We can sign with this descriptor (this is not true when actual BIP32 derivation is used, as that's not integrated in our signing code)
 
+/** Compare two descriptors. If only one of them has a checksum, the checksum is ignored. */
+bool EqualDescriptor(std::string a, std::string b)
+{
+    bool a_check = (a.size() > 9 && a[a.size() - 9] == '#');
+    bool b_check = (b.size() > 9 && b[b.size() - 9] == '#');
+    if (a_check != b_check) {
+        if (a_check) a = a.substr(0, a.size() - 9);
+        if (b_check) b = b.substr(0, b.size() - 9);
+    }
+    return a == b;
+}
+
 std::string MaybeUseHInsteadOfApostrophy(std::string ret)
 {
     if (InsecureRandBool()) {
@@ -35,6 +47,7 @@ std::string MaybeUseHInsteadOfApostrophy(std::string ret)
             auto it = ret.find("'");
             if (it != std::string::npos) {
                 ret[it] = 'h';
+                if (ret.size() > 9 && ret[ret.size() - 9] == '#') ret = ret.substr(0, ret.size() - 9); // Changing apostrophe to h breaks the checksum
             } else {
                 break;
             }
@@ -63,16 +76,16 @@ void Check(const std::string& prv, const std::string& pub, int flags, const std:
     // Check that both versions serialize back to the public version.
     std::string pub1 = parse_priv->ToString();
     std::string pub2 = parse_pub->ToString();
-    BOOST_CHECK_EQUAL(pub, pub1);
-    BOOST_CHECK_EQUAL(pub, pub2);
+    BOOST_CHECK(EqualDescriptor(pub, pub1));
+    BOOST_CHECK(EqualDescriptor(pub, pub2));
 
     // Check that both can be serialized with private key back to the private version, but not without private key.
     std::string prv1;
     BOOST_CHECK(parse_priv->ToPrivateString(keys_priv, prv1));
-    BOOST_CHECK_EQUAL(prv, prv1);
+    BOOST_CHECK(EqualDescriptor(prv, prv1));
     BOOST_CHECK(!parse_priv->ToPrivateString(keys_pub, prv1));
     BOOST_CHECK(parse_pub->ToPrivateString(keys_priv, prv1));
-    BOOST_CHECK_EQUAL(prv, prv1);
+    BOOST_CHECK(EqualDescriptor(prv, prv1));
     BOOST_CHECK(!parse_pub->ToPrivateString(keys_pub, prv1));
 
     // Check whether IsRange on both returns the expected result
@@ -210,6 +223,15 @@ BOOST_AUTO_TEST_CASE(descriptor_test)
     CheckUnparsable("wsh(sh(pk(L4rK1yDtCWekvXuE6oXD9jCYfFNV2cWRpVuPLBcCU2z8TrisoyY1)))", "wsh(sh(pk(03a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd)))"); // Cannot embed P2SH inside P2WSH
     CheckUnparsable("sh(sh(pk(L4rK1yDtCWekvXuE6oXD9jCYfFNV2cWRpVuPLBcCU2z8TrisoyY1)))", "sh(sh(pk(03a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd)))"); // Cannot embed P2SH inside P2SH
     CheckUnparsable("wsh(wsh(pk(L4rK1yDtCWekvXuE6oXD9jCYfFNV2cWRpVuPLBcCU2z8TrisoyY1)))", "wsh(wsh(pk(03a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd)))"); // Cannot embed P2WSH inside P2WSH
+
+    // Checksums
+    Check("sh(multi(2,[00000000/111'/222]xprvA1RpRA33e1JQ7ifknakTFpgNXPmW2YvmhqLQYMmrj4xJXXWYpDPS3xz7iAxn8L39njGVyuoseXzU6rcxFLJ8HFsTjSyQbLYnMpCqE2VbFWc,xprv9uPDJpEQgRQfDcW7BkF7eTya6RPxXeJCqCJGHuCJ4GiRVLzkTXBAJMu2qaMWPrS7AANYqdq6vcBcBUdJCVVFceUvJFjaPdGZ2y9WACViL4L/0))#ggrsrxfy", "sh(multi(2,[00000000/111'/222]xpub6ERApfZwUNrhLCkDtcHTcxd75RbzS1ed54G1LkBUHQVHQKqhMkhgbmJbZRkrgZw4koxb5JaHWkY4ALHY2grBGRjaDMzQLcgJvLJuZZvRcEL,xpub68NZiKmJWnxxS6aaHmn81bvJeTESw724CRDs6HbuccFQN9Ku14VQrADWgqbhhTHBaohPX4CjNLf9fq9MYo6oDaPPLPxSb7gwQN3ih19Zm4Y/0))#tjg09x5t", DEFAULT, {{"a91445a9a622a8b0a1269944be477640eedc447bbd8487"}}, {{0x8000006FUL,222},{0}});
+    Check("sh(multi(2,[00000000/111'/222]xprvA1RpRA33e1JQ7ifknakTFpgNXPmW2YvmhqLQYMmrj4xJXXWYpDPS3xz7iAxn8L39njGVyuoseXzU6rcxFLJ8HFsTjSyQbLYnMpCqE2VbFWc,xprv9uPDJpEQgRQfDcW7BkF7eTya6RPxXeJCqCJGHuCJ4GiRVLzkTXBAJMu2qaMWPrS7AANYqdq6vcBcBUdJCVVFceUvJFjaPdGZ2y9WACViL4L/0))", "sh(multi(2,[00000000/111'/222]xpub6ERApfZwUNrhLCkDtcHTcxd75RbzS1ed54G1LkBUHQVHQKqhMkhgbmJbZRkrgZw4koxb5JaHWkY4ALHY2grBGRjaDMzQLcgJvLJuZZvRcEL,xpub68NZiKmJWnxxS6aaHmn81bvJeTESw724CRDs6HbuccFQN9Ku14VQrADWgqbhhTHBaohPX4CjNLf9fq9MYo6oDaPPLPxSb7gwQN3ih19Zm4Y/0))", DEFAULT, {{"a91445a9a622a8b0a1269944be477640eedc447bbd8487"}}, {{0x8000006FUL,222},{0}});
+    CheckUnparsable("sh(multi(2,[00000000/111'/222]xprvA1RpRA33e1JQ7ifknakTFpgNXPmW2YvmhqLQYMmrj4xJXXWYpDPS3xz7iAxn8L39njGVyuoseXzU6rcxFLJ8HFsTjSyQbLYnMpCqE2VbFWc,xprv9uPDJpEQgRQfDcW7BkF7eTya6RPxXeJCqCJGHuCJ4GiRVLzkTXBAJMu2qaMWPrS7AANYqdq6vcBcBUdJCVVFceUvJFjaPdGZ2y9WACViL4L/0))#", "sh(multi(2,[00000000/111'/222]xpub6ERApfZwUNrhLCkDtcHTcxd75RbzS1ed54G1LkBUHQVHQKqhMkhgbmJbZRkrgZw4koxb5JaHWkY4ALHY2grBGRjaDMzQLcgJvLJuZZvRcEL,xpub68NZiKmJWnxxS6aaHmn81bvJeTESw724CRDs6HbuccFQN9Ku14VQrADWgqbhhTHBaohPX4CjNLf9fq9MYo6oDaPPLPxSb7gwQN3ih19Zm4Y/0))#"); // Empty checksum
+    CheckUnparsable("sh(multi(2,[00000000/111'/222]xprvA1RpRA33e1JQ7ifknakTFpgNXPmW2YvmhqLQYMmrj4xJXXWYpDPS3xz7iAxn8L39njGVyuoseXzU6rcxFLJ8HFsTjSyQbLYnMpCqE2VbFWc,xprv9uPDJpEQgRQfDcW7BkF7eTya6RPxXeJCqCJGHuCJ4GiRVLzkTXBAJMu2qaMWPrS7AANYqdq6vcBcBUdJCVVFceUvJFjaPdGZ2y9WACViL4L/0))#ggrsrxfyq", "sh(multi(2,[00000000/111'/222]xpub6ERApfZwUNrhLCkDtcHTcxd75RbzS1ed54G1LkBUHQVHQKqhMkhgbmJbZRkrgZw4koxb5JaHWkY4ALHY2grBGRjaDMzQLcgJvLJuZZvRcEL,xpub68NZiKmJWnxxS6aaHmn81bvJeTESw724CRDs6HbuccFQN9Ku14VQrADWgqbhhTHBaohPX4CjNLf9fq9MYo6oDaPPLPxSb7gwQN3ih19Zm4Y/0))#tjg09x5tq"); // Too long checksum
+    CheckUnparsable("sh(multi(2,[00000000/111'/222]xprvA1RpRA33e1JQ7ifknakTFpgNXPmW2YvmhqLQYMmrj4xJXXWYpDPS3xz7iAxn8L39njGVyuoseXzU6rcxFLJ8HFsTjSyQbLYnMpCqE2VbFWc,xprv9uPDJpEQgRQfDcW7BkF7eTya6RPxXeJCqCJGHuCJ4GiRVLzkTXBAJMu2qaMWPrS7AANYqdq6vcBcBUdJCVVFceUvJFjaPdGZ2y9WACViL4L/0))#ggrsrxf", "sh(multi(2,[00000000/111'/222]xpub6ERApfZwUNrhLCkDtcHTcxd75RbzS1ed54G1LkBUHQVHQKqhMkhgbmJbZRkrgZw4koxb5JaHWkY4ALHY2grBGRjaDMzQLcgJvLJuZZvRcEL,xpub68NZiKmJWnxxS6aaHmn81bvJeTESw724CRDs6HbuccFQN9Ku14VQrADWgqbhhTHBaohPX4CjNLf9fq9MYo6oDaPPLPxSb7gwQN3ih19Zm4Y/0))#tjg09x5"); // Too short checksum
+    CheckUnparsable("sh(multi(3,[00000000/111'/222]xprvA1RpRA33e1JQ7ifknakTFpgNXPmW2YvmhqLQYMmrj4xJXXWYpDPS3xz7iAxn8L39njGVyuoseXzU6rcxFLJ8HFsTjSyQbLYnMpCqE2VbFWc,xprv9uPDJpEQgRQfDcW7BkF7eTya6RPxXeJCqCJGHuCJ4GiRVLzkTXBAJMu2qaMWPrS7AANYqdq6vcBcBUdJCVVFceUvJFjaPdGZ2y9WACViL4L/0))#ggrsrxfy", "sh(multi(3,[00000000/111'/222]xpub6ERApfZwUNrhLCkDtcHTcxd75RbzS1ed54G1LkBUHQVHQKqhMkhgbmJbZRkrgZw4koxb5JaHWkY4ALHY2grBGRjaDMzQLcgJvLJuZZvRcEL,xpub68NZiKmJWnxxS6aaHmn81bvJeTESw724CRDs6HbuccFQN9Ku14VQrADWgqbhhTHBaohPX4CjNLf9fq9MYo6oDaPPLPxSb7gwQN3ih19Zm4Y/0))#tjg09x5t"); // Error in payload
+    CheckUnparsable("sh(multi(2,[00000000/111'/222]xprvA1RpRA33e1JQ7ifknakTFpgNXPmW2YvmhqLQYMmrj4xJXXWYpDPS3xz7iAxn8L39njGVyuoseXzU6rcxFLJ8HFsTjSyQbLYnMpCqE2VbFWc,xprv9uPDJpEQgRQfDcW7BkF7eTya6RPxXeJCqCJGHuCJ4GiRVLzkTXBAJMu2qaMWPrS7AANYqdq6vcBcBUdJCVVFceUvJFjaPdGZ2y9WACViL4L/0))#ggssrxfy", "sh(multi(2,[00000000/111'/222]xpub6ERApfZwUNrhLCkDtcHTcxd75RbzS1ed54G1LkBUHQVHQKqhMkhgbmJbZRkrgZw4koxb5JaHWkY4ALHY2grBGRjaDMzQLcgJvLJuZZvRcEL,xpub68NZiKmJWnxxS6aaHmn81bvJeTESw724CRDs6HbuccFQN9Ku14VQrADWgqbhhTHBaohPX4CjNLf9fq9MYo6oDaPPLPxSb7gwQN3ih19Zm4Y/0))#tjq09x4t"); // Error in checksum
 }
 
 BOOST_AUTO_TEST_SUITE_END()