1 files changed, 50 insertions, 0 deletions
diff --git a/data/basics/ccertpart.go b/data/basics/ccertpart.go
new file mode 100644
index 000000000..097cb6c27
--- /dev/null
+++ b/data/basics/ccertpart.go
@@ -0,0 +1,50 @@
+// Copyright (C) 2019-2021 Algorand, Inc.
+// This file is part of go-algorand
+//
+// go-algorand is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// go-algorand is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with go-algorand.  If not, see <https://www.gnu.org/licenses/>.
+
+package basics
+
+import (
+	"github.com/algorand/go-algorand/crypto"
+	"github.com/algorand/go-algorand/protocol"
+)
+
+// A Participant corresponds to an account whose AccountData.Status
+// is Online, and for which the expected sigRound satisfies
+// AccountData.VoteFirstValid <= sigRound <= AccountData.VoteLastValid.
+//
+// In the Algorand ledger, it is possible for multiple accounts to have
+// the same PK.  Thus, the PK is not necessarily unique among Participants.
+// However, each account will produce a unique Participant struct, to avoid
+// potential DoS attacks where one account claims to have the same VoteID PK
+// as another account.
+type Participant struct {
+	_struct struct{} `codec:",omitempty,omitemptyarray"`
+
+	// PK is AccountData.VoteID.
+	PK crypto.OneTimeSignatureVerifier `codec:"p"`
+
+	// Weight is AccountData.MicroAlgos.
+	Weight uint64 `codec:"w"`
+
+	// KeyDilution is AccountData.KeyDilution() with the protocol for sigRound
+	// as expected by the Builder.
+	KeyDilution uint64 `codec:"d"`
+}
+
+// ToBeHashed implements the crypto.Hashable interface.
+func (p Participant) ToBeHashed() (protocol.HashID, []byte) {
+	return protocol.CompactCertPart, protocol.Encode(&p)
+}