bolt11: add new test vector to test public key recovery from high-S signature

Author: erickcestari

11-payment-encoding.md

@@ -773,6 +773,34 @@ Breakdown:
 * `7hf8he7ecf7n4ffphs6awl9t6676rrclv9ckg3d3ncn7fct63p6s365duk5wrk202cfy3aj5xnnp5gs3vrdvruverwwq7yzhkf5a3xqp`: signature
 * `d05wjc`: Bech32 checksum
 
+> ### Public-key recovery with high-S signature
+> lnbc1pvjluezsp5zyg3zyg3zyg3zyg3zyg3zyg3zyg3zyg3zyg3zyg3zyg3zyg3zygspp5qqqsyqcyq5rqwzqfqqqsyqcyq5rqwzqfqqqsyqcyq5rqwzqfqypqdpl2pkx2ctnv5sxxmmwwd5kgetjypeh2ursdae8g6twvus8g6rfwvs8qun0dfjkxaq9qrsgq357wnc5r2ueh7ck6q93dj32dlqnls087fxdwk8qakdyafkq3yap2r09nt4ndd0unm3z9u5t48y6ucv4r5sg7lk98c77ctvjczkspk5qprc90gx
+
+Breakdown:
+
+* `lnbc`: prefix, Lightning on Bitcoin mainnet
+* `1`: Bech32 separator
+* `pvjluez`: timestamp (1496314658)
+* `s`: payment secret
+  * `p5`: `data_length` (`p` = 1, `5` = 20; 1 * 32 + 20 == 52)
+  * `zyg3zyg3zyg3zyg3zyg3zyg3zyg3zyg3zyg3zyg3zyg3zyg3zygs`: payment secret 1111111111111111111111111111111111111111111111111111111111111111
+* `p`: payment hash
+  * `p5`: `data_length` (`p` = 1, `5` = 20; 1 * 32 + 20 == 52)
+  * `qqqsyqcyq5rqwzqfqqqsyqcyq5rqwzqfqqqsyqcyq5rqwzqfqypq`: payment hash 0001020304050607080900010203040506070809000102030405060708090102
+* `d`: short description
+  * `pl`: `data_length` (`p` = 1, `l` = 31; 1 * 32 + 31 == 63)
+  * `2pkx2ctnv5sxxmmwwd5kgetjypeh2ursdae8g6twvus8g6rfwvs8qun0dfjkxaq`: 'Please consider supporting this project'
+* `9`: features
+  * `qr`: `data_length` (`q` = 0, `r` = 3; 0 * 32 + 3 == 3)
+  * `sgq`: b100000100000000
+* `357wnc5r2ueh7ck6q93dj32dlqnls087fxdwk8qakdyafkq3yap2r09nt4ndd0unm3z9u5t48y6ucv4r5sg7lk98c77ctvjczkspk5qp`: signature
+* `rc90gx`: Bech32 checksum
+* Signature breakdown:
+  * `8d3ce9e28357337f62da0162d9454df827f83cfe499aeb1c1db349d4d8112742a1bcb35d66d6bf93dc445e51753935cc32a3a411efd8a7c7bd85b25815a01b50` hex of signature data (32-byte r, 32-byte s)
+  * `1` (int) recovery flag contained in `signature`
+  * `6c6e62630b25fe64500d04444444444444444444444444444444444444444444444444444444444444444021a00008101820283038404800081018202830384048000810182028303840480810343f506c6561736520636f6e736964657220737570706f7274696e6720746869732070726f6a6563740500e08000` hex of data for signing (prefix + data after separator up to the start of the signature)
+  * `6daf4d488be41ce7cbb487cab1ef2975e5efcea879b20d421f0ef86b07cbb987` hex of SHA256 of the preimage
+
 # Examples of Invalid Invoices
 
 > # Same, but adding invalid unknown feature 100