diff --git a/src/server/activitypub.ts b/src/server/activitypub.ts
index 33120eafd018..ed8cffe4b916 100644
--- a/src/server/activitypub.ts
+++ b/src/server/activitypub.ts
@@ -42,17 +42,11 @@ async function inbox(ctx: Router.RouterContext) {
 	if (config.disableFederation) ctx.throw(404);
 
 	// parse body
-	const text = await coBody.text(ctx);
-
-	// check length
-	if (text.length > 65535) {
-		ctx.status = 413;
-		return;
-	}
-
-	// to json
-	const json = await JSON.parse(text);
-	ctx.request.body = json;
+	const { parsed, raw } = await coBody.json(ctx, {
+		limit: '64kb',
+		returnRawBody: true,
+	});
+	ctx.request.body = parsed;
 
 	let signature: httpSignature.IParsedSignature;
 
@@ -85,13 +79,13 @@ async function inbox(ctx: Router.RouterContext) {
 	const digestAlgo = match[1];
 	const digestExpected = match[2];
 
-	if (digestAlgo !== 'SHA-256') {	// TODO: lc?
+	if (digestAlgo.toUpperCase() !== 'SHA-256') {
 		logger.warn(`inbox: unsupported algorithm`);
 		ctx.status = 401;
 		return;
 	}
 
-	const digestActual = crypto.createHash('sha256').update(text).digest('base64')
+	const digestActual = crypto.createHash('sha256').update(raw).digest('base64')
 
 	if (digestExpected !== digestActual) {
 		logger.warn(`inbox: digest missmatch`);