diff --git a/src/ssn/readSsnFile.ts b/src/ssn/readSsnFile.ts
index 25d94c9..ad630fb 100644
--- a/src/ssn/readSsnFile.ts
+++ b/src/ssn/readSsnFile.ts
@@ -131,7 +131,7 @@ export default function readSsnFile(buffer: ArrayBuffer): ISsnFileEntry[] {
           //size of source file, is actually a uint64 but we only read 32-bits
           diffSourceLength = dv.getUint32(pos, true); pos += 8;
           //size of destination file, is actually a uint64 but we only read 32-bits
-          diffDestLength = dv.getUint32(pos + 12, true); pos += 8;
+          diffDestLength = dv.getUint32(pos, true); pos += 8;
           //skip 20 bytes: hash of old file
           //skip 20 bytes: hash of new file
           pos += 40;