feat: shared _reencrypt_all + reencrypt cmd + dual rekey (EGB-283)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

secrets

@@ -1772,6 +1772,78 @@ cmd_rm() {
   fi
 }
 
+# Decrypt every blob in the store with the local key and re-encrypt each to the
+# currently-loaded RECIPIENT_ARGS, then commit + push. The caller MUST have run
+# _load_recipients (or set RECIPIENT_ARGS) and check_key first. Aborts with the
+# store untouched on any decrypt failure (you must be a current recipient).
+# Shared by recipients add/rm, reencrypt, and multi-recipient rekey.
+_reencrypt_all() {
+  local commit_msg="$1"
+  local tmpdir
+  tmpdir=$(mktemp -d)
+  trap 'rm -rf "${tmpdir:-}"' EXIT INT TERM
+
+  info "Decrypting all blobs with your key..."
+  local file_count=0 dir project f rel dest
+  for dir in "$SECRETS_DIR"/*/; do
+    [ -d "$dir" ] || continue
+    project=$(basename "$dir")
+    case "$project" in .*) continue ;; esac
+    mkdir -p "$tmpdir/$project"
+    while IFS= read -r f; do
+      [ -f "$f" ] || continue
+      rel=${f#"$dir"}; rel=${rel%.age}
+      dest="$tmpdir/$project/$rel"
+      mkdir -p "$(dirname "$dest")"
+      if ! age -d -i "$KEY_FILE" -o "$dest" "$f"; then
+        die "Decryption failed for $project/$rel (are you a current recipient?). Aborted; store unchanged."
+      fi
+      file_count=$((file_count + 1))
+    done < <(find "$dir" -type f -name '*.age')
+  done
+
+  if [ "$file_count" -eq 0 ]; then
+    rm -rf "$tmpdir"; trap - EXIT INT TERM
+    info "No encrypted blobs in the store — nothing to re-encrypt."
+    return 0
+  fi
+
+  local rc=$(( ${#RECIPIENT_ARGS[@]} / 2 ))
+  info "Re-encrypting $file_count blob(s) to $rc recipient(s)..."
+  for dir in "$tmpdir"/*/; do
+    [ -d "$dir" ] || continue
+    project=$(basename "$dir")
+    mkdir -p "$SECRETS_DIR/$project"
+    while IFS= read -r f; do
+      [ -f "$f" ] || continue
+      rel=${f#"$dir"}
+      mkdir -p "$(dirname "$SECRETS_DIR/$project/$rel")"
+      age "${RECIPIENT_ARGS[@]}" -o "$SECRETS_DIR/$project/${rel}.age" "$f"
+    done < <(find "$dir" -type f)
+  done
+
+  ensure_store_protections
+  git -C "$SECRETS_DIR" add -A
+  git -C "$SECRETS_DIR" commit -m "$commit_msg" >/dev/null
+  if git -C "$SECRETS_DIR" remote get-url origin >/dev/null 2>&1; then
+    git -C "$SECRETS_DIR" push >/dev/null 2>&1
+    info "Pushed re-encrypted secrets to remote"
+  else
+    info "Committed re-encrypted secrets locally (no remote configured)"
+  fi
+  rm -rf "$tmpdir"; trap - EXIT INT TERM
+}
+
+cmd_reencrypt() {
+  check_cmd age
+  check_cmd git
+  resolve_store
+  check_initialized
+  check_key
+  _load_recipients
+  _reencrypt_all "reencrypt: re-encrypt all to current recipients"
+}
+
 cmd_rekey() {
   check_cmd age
   check_cmd git
@@ -1779,6 +1851,18 @@ cmd_rekey() {
   check_initialized
   check_key
 
+  # EGB-283: on a multi-recipient store, rekey means "re-encrypt every blob to
+  # the current recipients.txt set" — NOT a new keypair (rotating an identity is
+  # the member's own age-keygen + recipients rm/add). Legacy stores (no
+  # recipients.txt) keep the original generate-new-keypair behavior below.
+  if [ -e "$RECIPIENTS_FILE" ]; then
+    _load_recipients
+    info "Multi-recipient store — re-encrypting to $RECIPIENTS_FILE_NAME (no new key generated)."
+    _reencrypt_all "rekey: re-encrypt all to current recipients"
+    return 0
+  fi
+
+  # ── Legacy single-key rotation (unchanged) ──
   # Create temp dir with cleanup trap
   local tmpdir
   tmpdir=$(mktemp -d)
@@ -2612,6 +2696,7 @@ case "${1:-help}" in
   list)   cmd_list ;;
   rm)     cmd_rm "${2:-}" ;;
   rekey)      cmd_rekey ;;
+  reencrypt)  cmd_reencrypt ;;
   verify) shift; cmd_verify "$@" ;;
   migrate) shift; cmd_migrate "$@" ;;
   recipients) shift; cmd_recipients "$@" ;;

test/recipients.bats

@@ -76,3 +76,50 @@ make_second_identity() {
   [[ "$output" == *"alice"* ]] || false
   [[ "$output" == *"bob"* ]] || false
 }
+
+@test "reencrypt re-encrypts existing blobs to a newly added recipient line" {
+  init_with_remote
+  create_project_dir myproj
+  run "$SECRETS_BIN" push           # single-key blob (project name = "myproj"; blob at $SECRETS_DIR/myproj/.env.age)
+  [ "$status" -eq 0 ]
+  make_second_identity
+  STORE_PUB=$(age-keygen -y "$SECRETS_DIR/key.txt")
+  printf '%s\n%s\n' "$STORE_PUB" "$BOB_PUB" > "$SECRETS_DIR/recipients.txt"
+  # Bob cannot read the old single-key blob yet.
+  run age -d -i "$TEST_TMPDIR/bob.txt" "$SECRETS_DIR/myproj/.env.age"
+  [ "$status" -ne 0 ]
+  run "$SECRETS_BIN" reencrypt
+  [ "$status" -eq 0 ]
+  # Now he can.
+  run age -d -i "$TEST_TMPDIR/bob.txt" "$SECRETS_DIR/myproj/.env.age"
+  [ "$status" -eq 0 ]
+}
+
+@test "rekey on a multi-recipient store keeps recipients and the same key" {
+  init_with_remote
+  create_project_dir myproj
+  run "$SECRETS_BIN" push
+  before=$(cat "$SECRETS_DIR/key.txt")
+  make_second_identity
+  STORE_PUB=$(age-keygen -y "$SECRETS_DIR/key.txt")
+  printf '%s\n%s\n' "$STORE_PUB" "$BOB_PUB" > "$SECRETS_DIR/recipients.txt"
+  run "$SECRETS_BIN" rekey
+  [ "$status" -eq 0 ]
+  # No new keypair was generated.
+  [ "$(cat "$SECRETS_DIR/key.txt")" = "$before" ]
+  # Both recipients can decrypt.
+  run age -d -i "$TEST_TMPDIR/bob.txt" "$SECRETS_DIR/myproj/.env.age"
+  [ "$status" -eq 0 ]
+}
+
+@test "rekey on a legacy store still rotates to a new key (unchanged)" {
+  init_with_remote
+  create_project_dir myproj
+  run "$SECRETS_BIN" push
+  before=$(cat "$SECRETS_DIR/key.txt")
+  run "$SECRETS_BIN" rekey
+  [ "$status" -eq 0 ]
+  [ "$(cat "$SECRETS_DIR/key.txt")" != "$before" ]
+  run age -d -i "$SECRETS_DIR/key.txt" "$SECRETS_DIR/myproj/.env.age"
+  [ "$status" -eq 0 ]
+}