diff --git a/src/read.rs b/src/read.rs
index 119f51ba..0ab5acd2 100644
--- a/src/read.rs
+++ b/src/read.rs
@@ -8,7 +8,7 @@ use crate::crc32::Crc32Reader;
 use crate::extra_fields::{ExtendedTimestamp, ExtraField};
 use crate::read::zip_archive::Shared;
 use crate::result::{ZipError, ZipResult};
-use crate::spec::{self, Block};
+use crate::spec::{self, FixedSizeBlock};
 use crate::types::{
     AesMode, AesVendorVersion, DateTime, System, ZipCentralEntryBlock, ZipFileData,
     ZipLocalEntryBlock,
diff --git a/src/read/stream.rs b/src/read/stream.rs
index d87e22fc..8f2ffa0c 100644
--- a/src/read/stream.rs
+++ b/src/read/stream.rs
@@ -6,7 +6,7 @@ use super::{
     central_header_to_zip_file_inner, read_zipfile_from_stream, ZipCentralEntryBlock, ZipError,
     ZipFile, ZipFileData, ZipResult,
 };
-use crate::spec::Block;
+use crate::spec::FixedSizeBlock;
 
 /// Stream decoder for zip.
 #[derive(Debug)]
diff --git a/src/spec.rs b/src/spec.rs
index 8738a7bd..387259fd 100644
--- a/src/spec.rs
+++ b/src/spec.rs
@@ -97,7 +97,7 @@ impl ExtraFieldMagic {
 pub const ZIP64_BYTES_THR: u64 = u32::MAX as u64;
 pub const ZIP64_ENTRY_THR: usize = u16::MAX as usize;
 
-pub(crate) trait Block: Sized + Copy {
+pub(crate) trait FixedSizeBlock: Sized + Copy {
     const MAGIC: Magic;
 
     fn magic(self) -> Magic;
@@ -113,8 +113,10 @@ pub(crate) trait Block: Sized + Copy {
         Ok(block)
     }
 
-    fn deserialize(block: &[u8]) -> Self {
-        assert_eq!(block.len(), mem::size_of::<Self>());
+    fn deserialize(block: &[u8]) -> ZipResult<Self> {
+        if block.len() != mem::size_of::<Self>() {
+            return Err(ZipError::InvalidArchive("Block is wrong size"));
+        }
         let block_ptr: *const Self = block.as_ptr().cast();
         unsafe { block_ptr.read() }
     }
@@ -212,7 +214,7 @@ pub(crate) struct Zip32CDEBlock {
     pub zip_file_comment_length: u16,
 }
 
-impl Block for Zip32CDEBlock {
+impl FixedSizeBlock for Zip32CDEBlock {
     const MAGIC: Magic = Magic::CENTRAL_DIRECTORY_END_SIGNATURE;
 
     #[inline(always)]
@@ -391,7 +393,7 @@ pub(crate) struct Zip64CDELocatorBlock {
     pub number_of_disks: u32,
 }
 
-impl Block for Zip64CDELocatorBlock {
+impl FixedSizeBlock for Zip64CDELocatorBlock {
     const MAGIC: Magic = Magic::ZIP64_CENTRAL_DIRECTORY_END_LOCATOR_SIGNATURE;
 
     #[inline(always)]
@@ -467,7 +469,7 @@ pub(crate) struct Zip64CDEBlock {
     pub central_directory_offset: u64,
 }
 
-impl Block for Zip64CDEBlock {
+impl FixedSizeBlock for Zip64CDEBlock {
     const MAGIC: Magic = Magic::ZIP64_CENTRAL_DIRECTORY_END_SIGNATURE;
 
     fn magic(self) -> Magic {
@@ -708,7 +710,7 @@ mod test {
         pub file_name_length: u16,
     }
 
-    impl Block for TestBlock {
+    impl FixedSizeBlock for TestBlock {
         const MAGIC: Magic = Magic::literal(0x01111);
 
         fn magic(self) -> Magic {
diff --git a/src/types.rs b/src/types.rs
index 181592e6..f4d17acc 100644
--- a/src/types.rs
+++ b/src/types.rs
@@ -11,7 +11,7 @@ use std::sync::{Arc, OnceLock};
 use chrono::{Datelike, NaiveDate, NaiveDateTime, NaiveTime, Timelike};
 
 use crate::result::{ZipError, ZipResult};
-use crate::spec::{self, Block};
+use crate::spec::{self, FixedSizeBlock};
 
 pub(crate) mod ffi {
     pub const S_IFDIR: u32 = 0o0040000;
@@ -891,7 +891,7 @@ pub(crate) struct ZipCentralEntryBlock {
     pub offset: u32,
 }
 
-impl Block for ZipCentralEntryBlock {
+impl FixedSizeBlock for ZipCentralEntryBlock {
     const MAGIC: spec::Magic = spec::Magic::CENTRAL_DIRECTORY_HEADER_SIGNATURE;
 
     #[inline(always)]
@@ -938,7 +938,7 @@ pub(crate) struct ZipLocalEntryBlock {
     pub extra_field_length: u16,
 }
 
-impl Block for ZipLocalEntryBlock {
+impl FixedSizeBlock for ZipLocalEntryBlock {
     const MAGIC: spec::Magic = spec::Magic::LOCAL_FILE_HEADER_SIGNATURE;
 
     #[inline(always)]
diff --git a/src/write.rs b/src/write.rs
index 151258a8..acf9ac98 100644
--- a/src/write.rs
+++ b/src/write.rs
@@ -5,7 +5,7 @@ use crate::aes::AesWriter;
 use crate::compression::CompressionMethod;
 use crate::read::{find_content, Config, ZipArchive, ZipFile, ZipFileReader};
 use crate::result::{ZipError, ZipResult};
-use crate::spec::{self, Block};
+use crate::spec::{self, FixedSizeBlock};
 #[cfg(feature = "aes-crypto")]
 use crate::types::AesMode;
 use crate::types::{