diff --git a/swh/indexer/recompute.py b/swh/indexer/recompute.py
new file mode 100644
--- /dev/null
+++ b/swh/indexer/recompute.py
@@ -0,0 +1,99 @@
+# Copyright (C) 2017  The Software Heritage developers
+# See the AUTHORS file at the top-level directory of this distribution
+# License: GNU General Public License version 3, or any later version
+# See top-level LICENSE file for more information
+
+
+from swh.model import hashutil
+from swh.core import utils
+from swh.core.config import SWHConfig
+from swh.storage import get_storage
+
+
+class RecomputeChecksums(SWHConfig):
+    """Class in charge of (re)computing blob's hashes.
+
+    Hashes to compute are defined across 2 configuration options:
+
+    - compute-new-checksums ([str]): list of hash algorithms that
+      swh.model.hashutil.hashdata function should be able to deal
+      with.
+
+    - recompute-existing-checksums (bool): a boolean to notify that we
+      also want to recompute existing hash (as defined in
+      swh.model.hashutil.ALGORITHMS). As an important design detail,
+      there is currently one limitation about sha1. Since it's a
+      primary key on content, this cannot be updated so the
+      computations are skipped for that one.
+
+    """
+    DEFAULT_CONFIG = {
+        'storage': ('dict', {
+            'cls': 'remote',
+            'args': {
+              'url': 'http://localhost:5002/'
+            },
+        }),
+        # the set of checksums that should be computed. For
+        # variable-length checksums a desired checksum length should also
+        # be provided.
+        'compute-new-checksums': (
+            'list[str]', ['sha3:224', 'blake2:512']),
+        # whether checksums that already exist in the DB should be
+        # recomputed/updated or left untouched
+        'recompute-existing-checksums': ('bool', 'False'),
+        'batch': ('int', 100)
+    }
+
+    CONFIG_BASE_FILENAME = 'storage/recompute'
+
+    def __init__(self):
+        self.config = self.parse_config_file()
+        self.storage = get_storage(**self.config['storage'])
+        self.batch = self.config['batch']
+        self.compute_new_checksums = self.config['compute-new-checkums']
+        self.recompute_existing_checksums = set(self.config[
+            'recompute_existing_checksums'])
+
+    def run(self, ids):
+        """Given a list of ids, (re)compute a given set of checksums on
+            contents available in our object storage, and update the
+            content table accordingly.
+
+            Args:
+               ids ([bytes]): content identifier
+
+        """
+        # Determine what checksums to compute
+        checksums_algorithms = self.compute_new_checksums
+        if self.recompute_existing_checksums:
+            checksums_algorithms = checksums_algorithms + set(
+                hashutil.ALGORITHMS)
+
+        # Whatever the choice here, we cannot do a thing about sha1
+        # since it's the primary key, so removing it from the columns
+        # to update
+        keys_to_update = list(checksums_algorithms - set(['sha1']))
+
+        for content_ids in utils.grouper(ids, self.batch):
+            contents = self.storage.content_get_metadata(content_ids)
+
+            updated_contents = []
+            for content in contents:
+                raw_contents = list(self.storage.content_get([content['id']]))
+                if not raw_contents:  # unknown content
+                    continue
+
+                raw_content = raw_contents[0]['data']
+                updated_content = hashutil.hashdata(
+                    raw_content, algo=checksums_algorithms)
+
+                if updated_content['sha1'] != content['sha1']:
+                    self.log.error(
+                        "Corrupted content! Old sha1 %s and new one %s don't"
+                        " match." % (content['sha1'], updated_content['sha1']))
+                    continue
+
+                updated_contents.append(updated_content)
+
+            self.storage.content_update(updated_contents, keys=keys_to_update)