diff --git a/utils/src/bloom.c b/utils/src/bloom.c
new file mode 100644
index 00000000..22fa62a1
--- /dev/null
+++ b/utils/src/bloom.c
@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2016 Versity Software, Inc.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program 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
+ * General Public License for more details.
+ */
+#include "sparse.h"
+#include "util.h"
+#include "format.h"
+#include "bloom.h"
+#include "crc.h"
+#include "bitops.h"
+
+/* XXX garbage hack until we have siphash */
+static u32 bloom_hash(struct scoutfs_key *key, __le32 salt)
+{
+	return crc32c(le32_to_cpu(salt), key, sizeof(struct scoutfs_key));
+}
+
+/*
+ * Find the bits in the bloom filter for the given key.  The caller calculates
+ * these once and uses them to test all the blocks.
+ */
+void scoutfs_calc_bloom_bits(struct scoutfs_bloom_bits *bits,
+			     struct scoutfs_key *key, __le32 *salts)
+{
+	unsigned h_bits = 0;
+	unsigned s = 0;
+	u64 h = 0;
+	int i;
+
+	for (i = 0; i < SCOUTFS_BLOOM_BITS; i++) {
+		if (h_bits < SCOUTFS_BLOOM_BIT_WIDTH) {
+			h = (h << 32) | bloom_hash(key, salts[s++]);
+			h += 32;
+		}
+
+		bits->nr[i] = h & SCOUTFS_BLOOM_BIT_MASK;
+		h >>= SCOUTFS_BLOOM_BIT_WIDTH;
+		h_bits -= SCOUTFS_BLOOM_BIT_WIDTH;
+	}
+}
+
+/*
+ * This interface is different than in the kernel because we don't
+ * have a block IO interface here yet.  The caller gives us each
+ * bloom block and we set each bit that falls in the block.
+ */ 
+void scoutfs_set_bloom_bits(struct scoutfs_bloom_block *blm, unsigned int nr,
+			    struct scoutfs_bloom_bits *bits)
+{
+	int i;
+
+	for (i = 0; i < SCOUTFS_BLOOM_BITS; i++) {
+		if (nr == (bits->nr[i] / SCOUTFS_BLOOM_BITS_PER_BLOCK)) {
+			set_bit_le(bits->nr[i] % SCOUTFS_BLOOM_BITS_PER_BLOCK,
+				   blm->bits);
+		}
+	}
+}
diff --git a/utils/src/bloom.h b/utils/src/bloom.h
new file mode 100644
index 00000000..cad1639f
--- /dev/null
+++ b/utils/src/bloom.h
@@ -0,0 +1,13 @@
+#ifndef _BLOOM_H_
+#define _BLOOM_H_
+
+struct scoutfs_bloom_bits {
+	u32 nr[SCOUTFS_BLOOM_BITS];
+};
+
+void scoutfs_calc_bloom_bits(struct scoutfs_bloom_bits *bits,
+			     struct scoutfs_key *key, __le32 *salts);
+void scoutfs_set_bloom_bits(struct scoutfs_bloom_block *blm, unsigned int nr,
+			    struct scoutfs_bloom_bits *bits);
+
+#endif