diff --git a/include/aaruformat/context.h b/include/aaruformat/context.h
index 5725c2e..f67c234 100644
--- a/include/aaruformat/context.h
+++ b/include/aaruformat/context.h
@@ -25,6 +25,7 @@
 #include "md5.h"
 #include "sha1.h"
 #include "sha256.h"
+#include "spamsum.h"
 #include "structs.h"
 #include "utarray.h"
 
@@ -213,14 +214,16 @@ typedef struct aaruformatContext
     hash_map_t *sectorHashMap;  ///< Deduplication hash map (fingerprint->entry mapping).
     bool        deduplicate;    ///< Storage deduplication active (duplicates coalesce).
 
-    bool       rewinded;            ///< True if stream has been rewound after open (write path).
-    uint64_t   last_written_block;  ///< Last written block number (write path).
-    bool       calculating_md5;     ///< True if whole-image MD5 being calculated on-the-fly.
-    md5_ctx    md5_context;         ///< Opaque MD5 context for streaming updates
-    bool       calculating_sha1;    ///< True if whole-image SHA-1 being calculated on-the-fly.
-    sha1_ctx   sha1_context;        ///< Opaque SHA-1 context for streaming updates
-    bool       calculating_sha256;  ///< True if whole-image SHA-256 being calculated on-the-fly.
-    sha256_ctx sha256_context;      ///< Opaque SHA-256 context for streaming updates
+    bool         rewinded;             ///< True if stream has been rewound after open (write path).
+    uint64_t     last_written_block;   ///< Last written block number (write path).
+    bool         calculating_md5;      ///< True if whole-image MD5 being calculated on-the-fly.
+    md5_ctx      md5_context;          ///< Opaque MD5 context for streaming updates
+    bool         calculating_sha1;     ///< True if whole-image SHA-1 being calculated on-the-fly.
+    sha1_ctx     sha1_context;         ///< Opaque SHA-1 context for streaming updates
+    bool         calculating_sha256;   ///< True if whole-image SHA-256 being calculated on-the-fly.
+    sha256_ctx   sha256_context;       ///< Opaque SHA-256 context for streaming updates
+    bool         calculating_spamsum;  ///< True if whole-image SpamSum being calculated on-the-fly.
+    spamsum_ctx *spamsum_context;      ///< Opaque SpamSum context for streaming updates
 } aaruformatContext;
 
 /** \struct DumpHardwareEntriesWithData
diff --git a/include/aaruformat/spamsum.h b/include/aaruformat/spamsum.h
index 5f8c508..32ee7e7 100644
--- a/include/aaruformat/spamsum.h
+++ b/include/aaruformat/spamsum.h
@@ -21,8 +21,6 @@
 
 #include <stdint.h>
 
-#include "decls.h"
-
 #define SPAMSUM_LENGTH   64
 #define NUM_BLOCKHASHES  31
 #define ROLLING_WINDOW   7
diff --git a/src/close.c b/src/close.c
index 99ba33d..a634f50 100644
--- a/src/close.c
+++ b/src/close.c
@@ -516,6 +516,13 @@ int aaruf_close(void *context)
             ctx->checksums.hasSha256 = true;
             aaruf_sha256_final(&ctx->sha256_context, ctx->checksums.sha256);
         }
+        if(ctx->calculating_spamsum)
+        {
+            ctx->checksums.hasSpamSum = true;
+            ctx->checksums.spamsum    = calloc(1, FUZZY_MAX_RESULT);
+            aaruf_spamsum_final(ctx->spamsum_context, ctx->checksums.spamsum);
+            aaruf_spamsum_free(ctx->spamsum_context);
+        }
 
         // Write the checksums block
         bool has_checksums =
diff --git a/src/create.c b/src/create.c
index 9395325..e8d5a45 100644
--- a/src/create.c
+++ b/src/create.c
@@ -325,6 +325,11 @@ void *aaruf_create(const char *filepath, const uint32_t media_type, const uint32
         ctx->calculating_sha256 = true;
         aaruf_sha256_init(&ctx->sha256_context);
     }
+    if(parsed_options.spamsum)
+    {
+        ctx->calculating_spamsum = true;
+        ctx->spamsum_context = aaruf_spamsum_init();
+    }
 
     // Is writing
     ctx->isWriting = true;
diff --git a/src/write.c b/src/write.c
index 93be169..31d4914 100644
--- a/src/write.c
+++ b/src/write.c
@@ -158,6 +158,8 @@ int32_t aaruf_write_sector(void *context, uint64_t sector_address, bool negative
             if(ctx->calculating_sha1) ctx->calculating_sha1 = false;
             // Disable SHA256 calculation
             if(ctx->calculating_sha256) ctx->calculating_sha256 = false;
+            // Disable SpamSum calculation
+            if(ctx->calculating_spamsum) ctx->calculating_spamsum = false;
         }
         else
             ctx->last_written_block = sector_address;
@@ -172,6 +174,9 @@ int32_t aaruf_write_sector(void *context, uint64_t sector_address, bool negative
     // Calculate SHA256 on-the-fly if requested and sector is within user sectors (not negative or overflow)
     if(ctx->calculating_sha256 && !negative && sector_address <= ctx->imageInfo.Sectors)
         aaruf_sha256_update(&ctx->sha256_context, data, length);
+    // Calculate SpamSum on-the-fly if requested and sector is within user sectors (not negative or overflow)
+    if(ctx->calculating_sha256 && !negative && sector_address <= ctx->imageInfo.Sectors)
+        aaruf_spamsum_update(&ctx->spamsum_context, data, length);
 
     // TODO: If optical disc check track