diff --git a/lib/fetchers/directory.js b/lib/fetchers/directory.js
index 4f7f884..f6e680f 100644
--- a/lib/fetchers/directory.js
+++ b/lib/fetchers/directory.js
@@ -29,6 +29,7 @@ Fetcher.impl(fetchDirectory, {
         pkg._hasShrinkwrap = !!sr
         pkg._resolved = spec.fetchSpec
         pkg._integrity = false // Don't auto-calculate integrity
+        pkg._shasum = false // Don't auto-calculate shasum either
         return pkg
       }
     ).then(pkg => {
diff --git a/lib/fetchers/git.js b/lib/fetchers/git.js
index 6ce966a..66a2093 100644
--- a/lib/fetchers/git.js
+++ b/lib/fetchers/git.js
@@ -112,7 +112,8 @@ function plainManifest (repo, spec, opts) {
         _ref: ref,
         _rawRef: spec.gitCommittish || spec.gitRange,
         _uniqueResolved: resolved,
-        _integrity: false
+        _integrity: false,
+        _shasum: false
       }
     } else {
       // We're SOL and need a full clone :(
@@ -125,7 +126,8 @@ function plainManifest (repo, spec, opts) {
         _rawRef: rawRef,
         _resolved: rawRef && rawRef.match(/^[a-f0-9]{40}$/) && resolved,
         _uniqueResolved: rawRef && rawRef.match(/^[a-f0-9]{40}$/) && resolved,
-        _integrity: false
+        _integrity: false,
+        _shasum: false
       }
     }
   })
diff --git a/lib/finalize-manifest.js b/lib/finalize-manifest.js
index 0c0cc65..88e1e95 100644
--- a/lib/finalize-manifest.js
+++ b/lib/finalize-manifest.js
@@ -98,7 +98,7 @@ function Manifest (pkg, fromTarball, fullMetadata) {
   // and if they don't, we need to extract and read the tarball ourselves.
   // These are details required by the installer.
   this._integrity = pkg._integrity || fromTarball._integrity || null
-  this._shasum = pkg._shasum || null
+  this._shasum = pkg._shasum || fromTarball._shasum || null
   this._shrinkwrap = pkg._shrinkwrap || fromTarball._shrinkwrap || null
   this.bin = pkg.bin || fromTarball.bin || null
 
@@ -140,7 +140,9 @@ function tarballedProps (pkg, spec, opts) {
     pkg.directories &&
     pkg.directories.bin
   ))
-  const needsHash = !pkg || (!pkg._integrity && pkg._integrity !== false)
+  const needsIntegrity = !pkg || (!pkg._integrity && pkg._integrity !== false)
+  const needsShasum = !pkg || (!pkg._shasum && pkg._shasum !== false)
+  const needsHash = needsIntegrity || needsShasum
   const needsManifest = !pkg || !pkg.name
   const needsExtract = needsShrinkwrap || needsBin || needsManifest
   if (!needsShrinkwrap && !needsBin && !needsHash && !needsManifest) {
@@ -153,7 +155,7 @@ function tarballedProps (pkg, spec, opts) {
       needsShrinkwrap && jsonFromStream('npm-shrinkwrap.json', extracted),
       needsManifest && jsonFromStream('package.json', extracted),
       needsBin && getPaths(extracted),
-      needsHash && ssri.fromStream(tarStream),
+      needsHash && ssri.fromStream(tarStream, {algorithms: ['sha1', 'sha512']}),
       needsExtract && pipe(tarStream, extracted),
       (sr, mani, paths, hash) => {
         if (needsManifest && !mani) {
@@ -188,7 +190,8 @@ function tarballedProps (pkg, spec, opts) {
           _resolved: (mani && mani._resolved) ||
           (pkg && pkg._resolved) ||
           spec.fetchSpec,
-          _integrity: hash && hash.toString()
+          _integrity: needsIntegrity && hash && hash.sha512 && hash.sha512[0].toString(),
+          _shasum: needsShasum && hash && hash.sha1 && hash.sha1[0].hexDigest()
         })
       }
     )
diff --git a/test/finalize-manifest.js b/test/finalize-manifest.js
index 7fd1865..d9bca36 100644
--- a/test/finalize-manifest.js
+++ b/test/finalize-manifest.js
@@ -156,6 +156,33 @@ test('fills in integrity hash if missing', t => {
   })
 })
 
+test('fills in shasum if missing', t => {
+  const tarballPath = 'testing/tarball-1.2.3.tgz'
+  const base = {
+    name: 'testing',
+    version: '1.2.3',
+    _resolved: OPTS.registry + tarballPath,
+    _hasShrinkwrap: false
+  }
+  const sr = {
+    name: base.name,
+    version: base.version
+  }
+  return makeTarball({
+    'package.json': base,
+    'npm-shrinkwrap.json': sr
+  }).then(tarData => {
+    const shasum = ssri.fromData(tarData, {algorithms: ['sha1']}).hexDigest()
+    tnock(t, OPTS.registry).get('/' + tarballPath).reply(200, tarData)
+    return finalizeManifest(base, {
+      name: base.name,
+      type: 'range'
+    }, OPTS).then(manifest => {
+      t.deepEqual(manifest._shasum, shasum, 'shasum successfully added')
+    })
+  })
+})
+
 test('fills in `bin` if `directories.bin` string', t => {
   const tarballPath = 'testing/tarball-1.2.3.tgz'
   const base = {
@@ -203,6 +230,7 @@ test('fills in `bin` if original was an array', t => {
       bin: 'foo'
     },
     _integrity: 'sha1-deadbeefc0ffeebad1dea',
+    _shasum: '75e69d6de79f7347df79e6da77575e',
     _resolved: OPTS.registry + tarballPath,
     _hasShrinkwrap: false
   }
@@ -254,7 +282,7 @@ test('uses package.json as base if passed null', t => {
         _resolved: OPTS.registry + tarballPath,
         deprecated: false,
         _integrity: ssri.fromData(tarData, {algorithms: ['sha512']}).toString(),
-        _shasum: null, // shasums are only when provided
+        _shasum: ssri.fromData(tarData, {algorithms: ['sha1']}).hexDigest(),
         _shrinkwrap: sr,
         bin: { 'x': path.join('foo', 'x') },
         _id: 'testing@1.2.3'
diff --git a/test/registry.manifest.js b/test/registry.manifest.js
index 0d1759e..0dc354d 100644
--- a/test/registry.manifest.js
+++ b/test/registry.manifest.js
@@ -15,9 +15,11 @@ const BASE = {
   version: '1.2.3',
   _hasShrinkwrap: false,
   _integrity: 'sha1-deadbeef',
+  _shasum: '75e69d6de79f',
   _resolved: 'https://foo.bar/x.tgz',
   dist: {
     integrity: 'sha1-deadbeef',
+    shasum: '75e69d6de79f',
     tarball: 'https://foo.bar/x.tgz'
   }
 }
@@ -43,9 +45,11 @@ const META = {
       version: '2.0.4',
       _hasShrinkwrap: false,
       _integrity: 'sha1-deadbeef',
+      _shasum: '75e69d6de79f',
       _resolved: 'https://foo.bar/x.tgz',
       dist: {
         integrity: 'sha1-deadbeef',
+        shasum: '75e69d6de79f',
         tarball: 'https://foo.bar/x.tgz'
       }
     },
@@ -55,9 +59,11 @@ const META = {
       deprecated: 'yes. yes it is.',
       _hasShrinkwrap: false,
       _integrity: 'sha1-deadbeef',
+      _shasum: '75e69d6de79f',
       _resolved: 'https://foo.bar/x.tgz',
       dist: {
         integrity: 'sha1-deadbeef',
+        shasum: '75e69d6de79f',
         tarball: 'https://foo.bar/x.tgz'
       }
     },
@@ -317,9 +323,11 @@ test('package requests are case-sensitive', t => {
     version: '1.2.3',
     _hasShrinkwrap: false,
     _integrity: 'sha1-foobarbaz',
+    _shasum: '75e69d6de79f',
     _resolved: 'https://foo.bar/x.tgz',
     dist: {
       integrity: 'sha1-foobarbaz',
+      shasum: '75e69d6de79f',
       tarball: 'https://foo.bar/x.tgz'
     }
   }