0x06054b50

0x06054b50 is a 32‑bit hexadecimal constant that serves as the signature for the End of Central Directory (EOCD) record in the ZIP file format. The value corresponds to the ASCII characters “PK” followed by the bytes 0x05 and 0x06 when interpreted in little‑endian order, a pattern that identifies the concluding structure of a ZIP archive.

In a standard ZIP file, the EOCD record marks the end of the central directory, which contains metadata for each entry such as file names, compression methods, and offsets to the local file headers. The EOCD begins with the 0x06054b50 signature, followed by fields that specify the number of entries on the disk, total entries, size of the central directory, and the offset of the central directory from the start of the file. A 16‑bit comment length field may follow, allowing an optional archive comment.

The presence of the 0x06054b50 marker enables software to locate the EOCD efficiently, even in large archives, by scanning backward from the end of the file. This capability is essential for tools that need to read, modify, or verify ZIP archives without processing the entire file sequentially.

The signature is defined in the original PKZIP specification and is also referenced in the APPNOTE.TXT document maintained by the ZIP Format Alliance. Variants of the EOCD, such as ZIP64 extensions, use a different signature (0x06064b50) to accommodate archives larger than 4 GB.