1 files changed, 71 insertions, 0 deletions
diff --git a/log_parameters.go b/log_parameters.go
new file mode 100644
index 0000000..86ac0cc
--- /dev/null
+++ b/log_parameters.go
@@ -0,0 +1,71 @@
+package stfe
+
+import (
+	"crypto"
+	"fmt"
+	"time"
+
+	"crypto/rand"
+
+	"github.com/system-transparency/stfe/types"
+)
+
+// LogParameters is a collection of log parameters
+type LogParameters struct {
+	LogId      *types.Namespace     // log identifier
+	LogIdBytes []byte               // serialized log id
+	TreeId     int64                // used internally by Trillian
+	Prefix     string               // e.g., "test" for <base>/test
+	MaxRange   int64                // max entries per get-entries request
+	Submitters *types.NamespacePool // trusted submitters
+	Witnesses  *types.NamespacePool // trusted witnesses
+	Deadline   time.Duration        // gRPC deadline
+	Interval   time.Duration        // cosigning sth frequency
+	HashType   crypto.Hash          // hash function used by Trillian
+	Signer     crypto.Signer        // access to Ed25519 private key
+}
+
+// NewLogParameters creates newly initialized log parameters
+func NewLogParameters(signer crypto.Signer, logId *types.Namespace, treeId int64, prefix string, submitters, witnesses *types.NamespacePool, maxRange int64, interval, deadline time.Duration) (*LogParameters, error) {
+	logIdBytes, err := types.Marshal(*logId)
+	if err != nil {
+		return nil, fmt.Errorf("Marshal failed for log identifier: %v", err)
+	}
+	return &LogParameters{
+		LogId:      logId,
+		TreeId:     treeId,
+		Prefix:     prefix,
+		MaxRange:   maxRange,
+		Submitters: submitters,
+		Witnesses:  witnesses,
+		Deadline:   deadline,
+		Interval:   interval,
+		HashType:   crypto.SHA256,
+		Signer:     signer,
+		LogIdBytes: logIdBytes,
+	}, nil
+}
+
+// SignTreeHeadV1 signs a TreeHeadV1 structure
+func (lp *LogParameters) SignTreeHeadV1(th *types.TreeHeadV1) (*types.StItem, error) {
+	serialized, err := types.Marshal(*th)
+	if err != nil {
+		return nil, fmt.Errorf("Marshal failed for TreeHeadV1: %v", err)
+	}
+	sig, err := lp.Signer.Sign(rand.Reader, serialized, crypto.Hash(0))
+	if err != nil {
+		return nil, fmt.Errorf("Sign failed: %v", err)
+	}
+	lastSthTimestamp.Set(float64(time.Now().Unix()), string(lp.LogIdBytes))
+	lastSthSize.Set(float64(th.TreeSize), string(lp.LogIdBytes))
+	return &types.StItem{
+		Format: types.StFormatSignedTreeHeadV1,
+		SignedTreeHeadV1: &types.SignedTreeHeadV1{
+			TreeHead: *th,
+			Signature: types.SignatureV1{
+				Namespace: *lp.LogId,
+				Signature: sig,
+			},
+		},
+	}, nil
+}