diff --git a/tahoe-ssk.cabal b/tahoe-ssk.cabal
index 74708143905ccfb46f5dce6bc7dede91dd0c181f..a702a8a124a1a97a2f4ce4a7ee2161afc834d1a5 100644
--- a/tahoe-ssk.cabal
+++ b/tahoe-ssk.cabal
@@ -28,7 +28,9 @@ synopsis:
   An implementation of the Tahoe-LAFS SSK cryptographic protocols
 
 -- A longer description of the package.
--- description:
+description:
+  This currently includes a partial implementation of SDMF.  A future version
+  may include an implementation of MDMF.
 
 -- URL for the project homepage or repository.
 homepage:           https://whetstone.private.storage/PrivateStorage/tahoe-ssk
@@ -95,17 +97,17 @@ library
   build-depends:
     , asn1-encoding
     , asn1-types
-    , base
-    , base32
-    , binary
-    , bytestring
-    , cereal
-    , containers
-    , cryptonite
-    , megaparsec
-    , memory
-    , tahoe-capabilities
-    , text
+    , base                >=4.7      && <5
+    , base32              >=0.2.1    && <0.3
+    , binary              >=0.8.6    && <0.9
+    , bytestring          >=0.10.8.2 && <0.11
+    , cereal              >=0.5.8.1  && <0.6
+    , containers          >=0.6.0.1  && <0.7
+    , cryptonite          >=0.27     && <0.30
+    , megaparsec          >=8.0      && <9.3
+    , memory              >=0.15     && <0.17
+    , tahoe-capabilities  >=0.1      && <0.2
+    , text                >=1.2.3.1  && <1.3
     , x509
 
   -- This dependency isn't ideal.  Move common bits out to
@@ -136,21 +138,21 @@ test-suite tahoe-ssk-test
   build-depends:
     , asn1-encoding
     , asn1-types
-    , base
-    , base32
-    , binary
-    , bytestring
-    , cryptonite
-    , hedgehog
-    , megaparsec
-    , memory
-    , tahoe-capabilities
-    , tahoe-chk
+    , base                >=4.7      && <5
+    , base32              >=0.2.1    && <0.3
+    , binary              >=0.8.6    && <0.9
+    , bytestring          >=0.10.8.2 && <0.11
+    , cryptonite          >=0.27     && <0.30
+    , hedgehog            >=1.0.3    && <1.1
+    , megaparsec          >=8.0      && <9.3
+    , memory              >=0.15     && <0.17
+    , tahoe-capabilities  >=0.1      && <0.2
+    , tahoe-chk           >=0.1      && <0.2
     , tahoe-ssk
-    , tasty
-    , tasty-hedgehog
-    , tasty-hunit
-    , text
+    , tasty               >=1.2.3    && <1.5
+    , tasty-hedgehog      >=1.0.0.2  && <1.2
+    , tasty-hunit         >=0.10.0.2 && <0.11
+    , text                >=1.2.3.1  && <1.3
     , x509
 
 -- A helper for generating RSA key pairs for use by the test suite.
@@ -178,11 +180,11 @@ executable encode-ssk
   main-is:        Main.hs
   hs-source-dirs: encode-ssk
   build-depends:
-    , base
-    , base32
-    , binary
-    , bytestring
-    , cryptonite
-    , tahoe-capabilities
+    , base                >=4.7      && <5
+    , base32              >=0.2.1    && <0.3
+    , binary              >=0.8.6    && <0.9
+    , bytestring          >=0.10.8.2 && <0.11
+    , cryptonite          >=0.27     && <0.30
+    , tahoe-capabilities  >=0.1      && <0.2
     , tahoe-ssk
-    , text
+    , text                >=1.2.3.1  && <1.3