diff --git a/eth/keyfile/uuid.nim b/eth/keyfile/uuid.nim
index 943e3ef..59986be 100644
--- a/eth/keyfile/uuid.nim
+++ b/eth/keyfile/uuid.nim
@@ -21,7 +21,7 @@
 import nimcrypto/utils, endians
 
 type
-  UUIDException = object of Exception
+  UUIDException = object of CatchableError
 
   UUID* = object
     ## Represents UUID object
diff --git a/eth/keys.nim b/eth/keys.nim
index 8e41700..dc03690 100644
--- a/eth/keys.nim
+++ b/eth/keys.nim
@@ -13,7 +13,7 @@ type
     Success,  ## Operation was successful
     Error     ## Operation failed
 
-  EthKeysException* = object of Exception
+  EthKeysException* = object of CatchableError
     ## Exception generated by this module
 
 when not defined(native):
diff --git a/eth/keys/libsecp256k1.nim b/eth/keys/libsecp256k1.nim
index fe589c4..0d0621f 100644
--- a/eth/keys/libsecp256k1.nim
+++ b/eth/keys/libsecp256k1.nim
@@ -50,7 +50,7 @@ type
   SignatureNR* = secp256k1_ecdsa_signature
     ## Representation of non-recoverable signature
 
-  Secp256k1Exception* = object of Exception
+  Secp256k1Exception* = object of CatchableError
     ## Exceptions generated by `libsecp256k1`
 
   EthKeysContext = ref object
diff --git a/eth/p2p/auth.nim b/eth/p2p/auth.nim
index 875ffd1..12760c6 100644
--- a/eth/p2p/auth.nim
+++ b/eth/p2p/auth.nim
@@ -79,7 +79,7 @@ type
     egressMac*: keccak256
     ingressMac*: keccak256
 
-  AuthException* = object of Exception
+  AuthException* = object of CatchableError
 
 template toa(a, b, c: untyped): untyped =
   toOpenArray((a), (b), (b) + (c) - 1)
diff --git a/eth/p2p/ecies.nim b/eth/p2p/ecies.nim
index e60703d..0f276d1 100644
--- a/eth/p2p/ecies.nim
+++ b/eth/p2p/ecies.nim
@@ -16,7 +16,7 @@ const
   emptyMac* = array[0, byte]([])
 
 type
-  EciesException* = object of Exception
+  EciesException* = object of CatchableError
   EciesStatus* = enum
     Success,        ## Operation was successful
     BufferOverrun,  ## Output buffer size is too small
diff --git a/eth/p2p/enode.nim b/eth/p2p/enode.nim
index 8d6029e..342e4b0 100644
--- a/eth/p2p/enode.nim
+++ b/eth/p2p/enode.nim
@@ -34,7 +34,7 @@ type
     pubkey*: PublicKey    ## Node public key
     address*: Address     ## Node address
 
-  ENodeException* = object of Exception
+  ENodeException* = object of CatchableError
 
 proc raiseENodeError(status: ENodeStatus) =
   if status == IncorrectIP:
diff --git a/eth/p2p/rlpx_protocols/les/private/les_types.nim b/eth/p2p/rlpx_protocols/les/private/les_types.nim
index 5a22453..b84992e 100644
--- a/eth/p2p/rlpx_protocols/les/private/les_types.nim
+++ b/eth/p2p/rlpx_protocols/les/private/les_types.nim
@@ -95,7 +95,7 @@ type
     key*: string
     value*: Blob
 
-  HandshakeError* = object of Exception
+  HandshakeError* = object of CatchableError
 
   LesTime* = int # this is in milliseconds
   BufValueInt* = int
diff --git a/eth/rlp/writer.nim b/eth/rlp/writer.nim
index 5663cd9..b082f3f 100644
--- a/eth/rlp/writer.nim
+++ b/eth/rlp/writer.nim
@@ -11,8 +11,6 @@ type
     pendingLists: seq[tuple[remainingItems, outBytes: int]]
     output: Bytes
 
-  PrematureFinalizationError* = object of Exception
-
   IntLike* = concept x, y
     type T = type(x)
 
@@ -256,9 +254,7 @@ proc initRlpList*(listSize: int): RlpWriter =
 
 # TODO: This should return a lent value
 proc finish*(self): Bytes =
-  if pendingLists.len > 0:
-    raise newException(PrematureFinalizationError,
-      "Insufficient number of elements written to a started list")
+  doAssert pendingLists.len == 0, "Insufficient number of elements written to a started list"
   result = output
 
 proc encode*[T](v: T): Bytes =
diff --git a/eth/trie/backends/backend_defs.nim b/eth/trie/backends/backend_defs.nim
index 6ab3212..63ec446 100644
--- a/eth/trie/backends/backend_defs.nim
+++ b/eth/trie/backends/backend_defs.nim
@@ -1,5 +1,5 @@
 type
-  StorageError* = object of Exception
+  StorageError* = object of CatchableError
 
 template raiseStorageInitError* =
   raise newException(StorageError, "failure to initialize storage")
diff --git a/eth/trie/binaries.nim b/eth/trie/binaries.nim
index 3a81161..a81b40d 100644
--- a/eth/trie/binaries.nim
+++ b/eth/trie/binaries.nim
@@ -1,6 +1,6 @@
 import
   sequtils,
-  stew/ranges/[ptr_arith, bitranges], eth/rlp/types
+  stew/ranges/[ptr_arith, bitranges], eth/rlp/types, trie_defs
 
 type
   TrieNodeKind* = enum
@@ -22,8 +22,8 @@ type
     of LEAF_TYPE:
       value*: BytesRange
 
-  InvalidNode* = object of Exception
-  ValidationError* = object of Exception
+  InvalidNode* = object of CorruptedTrieDatabase
+  ValidationError* = object of CorruptedTrieDatabase
 
 # ----------------------------------------------
 template sliceToEnd*(r: TrieBitRange, index: int): TrieBitRange =
diff --git a/eth/trie/binary.nim b/eth/trie/binary.nim
index 9c8e7b8..44518a2 100644
--- a/eth/trie/binary.nim
+++ b/eth/trie/binary.nim
@@ -12,7 +12,7 @@ type
     db: DB
     rootHash: TrieNodeKey
 
-  NodeOverrideError* = object of Exception
+  NodeOverrideError* = object of CatchableError
 
 let
   zeroHash* = zeroBytesRange
diff --git a/eth/trie/branches.nim b/eth/trie/branches.nim
index bf902a8..8322a2f 100644
--- a/eth/trie/branches.nim
+++ b/eth/trie/branches.nim
@@ -4,7 +4,9 @@ import
 
 type
   DB = TrieDatabaseRef
-  InvalidKeyError* = object of Exception
+
+  # TODO: replace the usages of this with regular asserts
+  InvalidKeyError* = object of Defect
 
 template query(db: DB, nodeHash: TrieNodeKey): BytesRange =
   db.get(nodeHash.toOpenArray).toRange
diff --git a/eth/trie/hexary.nim b/eth/trie/hexary.nim
index 2f597c3..0bb4481 100644
--- a/eth/trie/hexary.nim
+++ b/eth/trie/hexary.nim
@@ -19,10 +19,6 @@ type
 
   TrieNode = Rlp
 
-  TrieError* = object of Exception
-  CorruptedTrieError* = object of TrieError
-  PersistenceFailure* = object of TrieError
-
 template len(key: TrieNodeKey): int =
   key.usedBytes.int
 
@@ -133,7 +129,7 @@ proc getAux(db: DB, nodeRlp: Rlp, path: NibblesRange): BytesRange =
       let nextLookup = branch.getLookup
       return getAux(db, nextLookup, path.slice(1))
   else:
-    raise newException(CorruptedTrieError,
+    raise newException(CorruptedTrieDatabase,
                        "HexaryTrie node with an unexpected number of children")
 
 proc get*(self: HexaryTrie; key: BytesRange): BytesRange =
@@ -173,7 +169,7 @@ proc getKeysAux(db: DB, stack: var seq[tuple[nodeRlp: Rlp, path: NibblesRange]])
         doAssert(path.len mod 2 == 0)
         return path.getBytes
     else:
-      raise newException(CorruptedTrieError,
+      raise newException(CorruptedTrieDatabase,
                         "HexaryTrie node with an unexpected number of children")
 
 iterator keys*(self: HexaryTrie): BytesRange =
@@ -212,7 +208,7 @@ proc getValuesAux(db: DB, stack: var seq[Rlp]): BytesRange =
       if not lastElem.isEmpty:
         return lastElem.toBytes
     else:
-      raise newException(CorruptedTrieError,
+      raise newException(CorruptedTrieDatabase,
                         "HexaryTrie node with an unexpected number of children")
 
 iterator values*(self: HexaryTrie): BytesRange =
@@ -255,7 +251,7 @@ proc getPairsAux(db: DB, stack: var seq[tuple[nodeRlp: Rlp, path: NibblesRange]]
         doAssert(path.len mod 2 == 0)
         return (path.getBytes, lastElem.toBytes)
     else:
-      raise newException(CorruptedTrieError,
+      raise newException(CorruptedTrieDatabase,
                         "HexaryTrie node with an unexpected number of children")
 
 iterator pairs*(self: HexaryTrie): (BytesRange, BytesRange) =
@@ -311,7 +307,7 @@ iterator replicate*(self: HexaryTrie): (BytesRange, BytesRange) =
           key.replaceLastNibble(i.byte)
           pushOrYield(branch)
     else:
-      raise newException(CorruptedTrieError,
+      raise newException(CorruptedTrieDatabase,
                         "HexaryTrie node with an unexpected number of children")
 
 proc getValues*(self: HexaryTrie): seq[BytesRange] =
@@ -350,7 +346,7 @@ proc getBranchAux(db: DB, node: BytesRange, path: NibblesRange, output: var seq[
         output.add nextLookup
         getBranchAux(db, nextLookup, path.slice(1), output)
   else:
-    raise newException(CorruptedTrieError,
+    raise newException(CorruptedTrieDatabase,
                        "HexaryTrie node with an unexpected number of children")
 
 proc getBranch*(self: HexaryTrie; key: BytesRange): seq[BytesRange] =
diff --git a/eth/trie/trie_defs.nim b/eth/trie/trie_defs.nim
index e7a3271..72eb2a4 100644
--- a/eth/trie/trie_defs.nim
+++ b/eth/trie/trie_defs.nim
@@ -8,6 +8,18 @@ type
   KeccakHash* = MDigest[256]
   BytesContainer* = ByteRange | Bytes | string
 
+  TrieError* = object of CatchableError
+    # A common base type of all Trie errors.
+
+  PersistenceFailure* = object of TrieError
+    # The backing database of the trie was not able to carry out
+    # the storage or retrieval request.
+
+  CorruptedTrieDatabase* = object of Defect
+    # We consider this a Defect, because the software cannot safely
+    # operate if its database has been tampered with. A swift crash
+    # will be a more appropriate response.
+
 # can't be a const: https://github.com/status-im/nim-eth/issues/6
 # we can't initialise it here, but since it's already zeroed memory, we don't need to
 var zeroBytesRange* {.threadvar.}: ByteRange