From bd2061956b8b696b277c74650818f9cefe032547 Mon Sep 17 00:00:00 2001
From: Francisco Gindre <francisco@z.cash>
Date: Fri, 24 Jun 2022 14:27:07 -0300
Subject: [PATCH] [#585] Add checkpoints for Orchard Activation Height (#586)

* [#585] Add checkpoints for Orchard Activation Height

Closes #585

these checkpoints will be useful for wallets supporting orchard
that had existing orchard activity from activation height on and
after NU5 SDK support is implemented they need to rescan for orchard
funds.

* Add documentation on special checkpoints

Co-authored-by: Carter Jernigan <git@carterjernigan.com>
---
 README.md                                              | 10 ++++++++++
 .../checkpoint/mainnet/1687104.json                    |  8 ++++++++
 .../checkpoint/testnet/1842420.json                    |  8 ++++++++
 3 files changed, 26 insertions(+)
 create mode 100644 sdk-lib/src/main/assets/co.electriccoin.zcash/checkpoint/mainnet/1687104.json
 create mode 100644 sdk-lib/src/main/assets/co.electriccoin.zcash/checkpoint/testnet/1842420.json

diff --git a/README.md b/README.md
index e5d98b6c..5ce2b303 100644
--- a/README.md
+++ b/README.md
@@ -205,6 +205,16 @@ To improve the speed of syncing with the Zcash network, the SDK contains a serie
 
 To update the checkpoints, see [Checkmate](https://github.com/zcash-hackworks/checkmate).
 
+We generally recommend adding new checkpoints every few weeks.  By convention, checkpoints are added in block increments of 10,000 which provides a reasonable tradeoff in terms of number of checkpoints versus performance.
+
+There are two special checkpoints, one for sapling activation and another for orchard activation.  These are mentioned because they don't follow the "round 10,000" rule.
+ * Sapling activation
+     * Mainnet: 419200
+     * Testnet: 280000
+ * Orchard activation
+     * Mainnet: 1687104
+     * Testnet: 1842420
+
 ## Publishing
 
 Publishing instructions for maintainers of this repository can be found in [PUBLISHING.md](PUBLISHING.md)
diff --git a/sdk-lib/src/main/assets/co.electriccoin.zcash/checkpoint/mainnet/1687104.json b/sdk-lib/src/main/assets/co.electriccoin.zcash/checkpoint/mainnet/1687104.json
new file mode 100644
index 00000000..54cea28e
--- /dev/null
+++ b/sdk-lib/src/main/assets/co.electriccoin.zcash/checkpoint/mainnet/1687104.json
@@ -0,0 +1,8 @@
+{
+  "network": "main",
+  "height": "1687104",
+  "hash": "0000000000d723156d9b65ffcf4984da7a19675ed7e2f06d9e5d5188af087bf8",
+  "time": 1654019405,
+  "saplingTree": "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",
+  "orchardTree": "000000"
+}
diff --git a/sdk-lib/src/main/assets/co.electriccoin.zcash/checkpoint/testnet/1842420.json b/sdk-lib/src/main/assets/co.electriccoin.zcash/checkpoint/testnet/1842420.json
new file mode 100644
index 00000000..4f5396a4
--- /dev/null
+++ b/sdk-lib/src/main/assets/co.electriccoin.zcash/checkpoint/testnet/1842420.json
@@ -0,0 +1,8 @@
+{
+  "network": "test",
+  "height": "1842420",
+  "hash": "0006d75c60b3093d1b671ff7da11c99ea535df9927c02e6ed9eb898605eb7381",
+  "time": 1650360552,
+  "saplingTree": "011943e7b8f4187ac97b1968b0c7ebde20d4c0d6be3cb86885e1a812c66da4512d001001099286d1d7ad904b1c398f4950c8d78377e19b47ae0ebecbc8788446547bb5530000015020d0a93940caf0c9208e97b7525d241b13e64fcd1ca3fc6f2009bdcf732502000000017bbe520c0277c9670a339e80f676ba8393f338c7adbcb1a20a03ded90c9efd4000000000000117ddeb3a5f8d2f6b2d0a07f28f01ab25e03a05a9319275bb86d72fcaef6fc01501f08f39275112dd8905b854170b7f247cf2df18454d4fa94e6e4f9320cca05f24011f8322ef806eb2430dc4a7a41c1b344bea5be946efc7b4349c1c9edb14ff9d39",
+  "orchardTree": "000000"
+}