diff --git a/.github/workflows/ci_verification.yml b/.github/workflows/ci_verification.yml
index c0f666b4c..31b53fcae 100644
--- a/.github/workflows/ci_verification.yml
+++ b/.github/workflows/ci_verification.yml
@@ -50,7 +50,7 @@ jobs:
         uses: dafny-lang/setup-dafny-action@v1.7.0
         with:
           # A && B || C is the closest thing to an if .. then ... else ... or ?: expression the GitHub Actions syntax supports.
-          dafny-version: ${{ (github.event_name == 'schedule' || inputs.nightly) && 'nightly-latest' || '4.2.0' }}
+          dafny-version: ${{ (github.event_name == 'schedule' || inputs.nightly) && 'nightly-latest' || '4.6.0' }}
 
       - name: Regenerate code using smithy-dafny if necessary
         if: ${{ inputs.nightly }}
diff --git a/DynamoDbEncryption/dafny/DynamoDbEncryption/src/DynamoToStruct.dfy b/DynamoDbEncryption/dafny/DynamoDbEncryption/src/DynamoToStruct.dfy
index 604478c51..616dfe404 100644
--- a/DynamoDbEncryption/dafny/DynamoDbEncryption/src/DynamoToStruct.dfy
+++ b/DynamoDbEncryption/dafny/DynamoDbEncryption/src/DynamoToStruct.dfy
@@ -357,6 +357,9 @@ module DynamoToStruct {
               && U32ToBigEndian(|a.L|).Success?
               && |ret.value| >= PREFIX_LEN + LENGTH_LEN
               && ret.value[0..TYPEID_LEN] == SE.LIST
+              && ListAttrToBytes(a.L, depth).Success?
+              && ret.value[PREFIX_LEN..] == ListAttrToBytes(a.L, depth).value
+              && ListAttrToBytes(a.L, depth).value[..LENGTH_LEN] == U32ToBigEndian(|a.L|).value
               && ret.value[PREFIX_LEN..PREFIX_LEN+LENGTH_LEN] == U32ToBigEndian(|a.L|).value
               && (|a.L| == 0 ==> |ret.value| == PREFIX_LEN + LENGTH_LEN)
 
@@ -492,6 +495,10 @@ module DynamoToStruct {
   }
 
   function method ListAttrToBytes(l: ListAttributeValue, depth : nat): (ret: Result<seq<uint8>, string>)
+    ensures ret.Success? ==>
+              && U32ToBigEndian(|l|).Success?
+              && LENGTH_LEN <= |ret.value|
+              && ret.value[..LENGTH_LEN] == U32ToBigEndian(|l|).value
   {
     var count :- U32ToBigEndian(|l|);
     var body :- CollectList(l, depth);
diff --git a/DynamoDbEncryption/dafny/DynamoDbEncryption/test/DynamoDbEncryptionBranchKeyIdSupplierTest.dfy b/DynamoDbEncryption/dafny/DynamoDbEncryption/test/DynamoDbEncryptionBranchKeyIdSupplierTest.dfy
index 02469a5f2..74e12264f 100644
--- a/DynamoDbEncryption/dafny/DynamoDbEncryption/test/DynamoDbEncryptionBranchKeyIdSupplierTest.dfy
+++ b/DynamoDbEncryption/dafny/DynamoDbEncryption/test/DynamoDbEncryptionBranchKeyIdSupplierTest.dfy
@@ -43,8 +43,10 @@ module DynamoDbEncryptionBranchKeyIdSupplierTest {
   const BRANCH_KEY_ID_B := ALTERNATE_BRANCH_KEY_ID
   const EC_PARTITION_NAME := UTF8.EncodeAscii("aws-crypto-partition-name")
   const RESERVED_PREFIX := "aws-crypto-attr."
+  const KEY_ATTR_NAME := UTF8.EncodeAscii(RESERVED_PREFIX + BRANCH_KEY)
+  const BRANCH_KEY_NAME := UTF8.EncodeAscii(BRANCH_KEY)
 
-  method {:test} TestHappyCase()
+  method {:test} {:vcs_split_on_every_assert} TestHappyCase()
   {
     var ddbKeyToBranchKeyId: Types.IDynamoDbKeyBranchKeyIdSupplier := new TestBranchKeyIdSupplier();
     var ddbEncResources :- expect DynamoDbEncryption.DynamoDbEncryption();
@@ -80,13 +82,12 @@ module DynamoDbEncryptionBranchKeyIdSupplierTest {
       )
     );
 
-    var keyAttrName := UTF8.EncodeAscii(RESERVED_PREFIX + BRANCH_KEY);
 
     // Test Encryption Context with Case A
     var materials :- expect mpl.InitializeEncryptionMaterials(
       MPL.InitializeEncryptionMaterialsInput(
         algorithmSuiteId := TEST_DBE_ALG_SUITE_ID,
-        encryptionContext := map[EC_PARTITION_NAME := UTF8.EncodeAscii(BRANCH_KEY)],
+        encryptionContext := map[EC_PARTITION_NAME := BRANCH_KEY_NAME],
         requiredEncryptionContextKeys := [],
         signingKey := None,
         verificationKey := None
@@ -94,13 +95,13 @@ module DynamoDbEncryptionBranchKeyIdSupplierTest {
     );
 
     var caseA :- expect UTF8.Encode(Base64.Encode(CASE_A_BYTES));
-    var contextCaseA := materials.encryptionContext[keyAttrName := caseA];
+    var contextCaseA := materials.encryptionContext[KEY_ATTR_NAME := caseA];
     var materialsA := materials.(encryptionContext := contextCaseA);
     TestRoundtrip(hierarchyKeyring, materialsA, TEST_DBE_ALG_SUITE_ID, BRANCH_KEY_ID_A);
 
     // Test Encryption Context with Case B
     var caseB :- expect UTF8.Encode(Base64.Encode(CASE_B_BYTES));
-    var contextCaseB := materials.encryptionContext[keyAttrName := caseB];
+    var contextCaseB := materials.encryptionContext[KEY_ATTR_NAME := caseB];
     var materialsB := materials.(encryptionContext := contextCaseB);
     TestRoundtrip(hierarchyKeyring, materialsB, TEST_DBE_ALG_SUITE_ID, BRANCH_KEY_ID_B);
   }
diff --git a/DynamoDbEncryption/dafny/StructuredEncryption/src/Canonize.dfy b/DynamoDbEncryption/dafny/StructuredEncryption/src/Canonize.dfy
index 16c1f3771..4bf84c2cb 100644
--- a/DynamoDbEncryption/dafny/StructuredEncryption/src/Canonize.dfy
+++ b/DynamoDbEncryption/dafny/StructuredEncryption/src/Canonize.dfy
@@ -667,6 +667,7 @@ module {:options "/functionSyntax:4" } Canonize {
     forall i | 0 <= i < |input| ensures exists x :: x in origData && Updated2(x, input[i], DoDecrypt) {
       var x :| x in origData && Updated2(x, input[i], DoDecrypt);
     }
+    assert forall i | 0 <= i < |input| :: exists x :: x in origData && Updated2(x, input[i], DoDecrypt);
   }
 
   // command line tools that say /vcsSplitOnEveryAssert fail without the {:vcs_split_on_every_assert false}
@@ -678,6 +679,7 @@ module {:options "/functionSyntax:4" } Canonize {
     forall i | 0 <= i < |input| ensures exists x :: x in origData && Updated5(x, input[i], DoEncrypt) {
       var x :| x in origData && Updated5(x, input[i], DoEncrypt);
     }
+    assert forall i | 0 <= i < |input| :: exists x :: x in origData && Updated5(x, input[i], DoEncrypt);
   }
 
   lemma CryptoUpdatedAuthMaps(origData : AuthList, input : CanonCryptoList, output : CryptoList)
diff --git a/DynamoDbEncryption/dafny/StructuredEncryption/src/SortCanon.dfy b/DynamoDbEncryption/dafny/StructuredEncryption/src/SortCanon.dfy
index 1fb2832cb..1033d899e 100644
--- a/DynamoDbEncryption/dafny/StructuredEncryption/src/SortCanon.dfy
+++ b/DynamoDbEncryption/dafny/StructuredEncryption/src/SortCanon.dfy
@@ -222,6 +222,7 @@ module SortCanon {
     ensures multiset(x) == multiset(result)
     ensures SortedBy(result, AuthBelow)
     ensures CanonAuthListHasNoDuplicates(result)
+    ensures |result| == |x|
   {
     AuthBelowIsTotal();
     var ret := MergeSortBy(x, AuthBelow);
@@ -236,6 +237,7 @@ module SortCanon {
     ensures multiset(result) == multiset(x)
     ensures SortedBy(result, CryptoBelow)
     ensures CanonCryptoListHasNoDuplicates(result)
+    ensures |result| == |x|
   {
     CryptoBelowIsTotal();
     var ret := MergeSortBy(x, CryptoBelow);