Checksum Calculation

Hex Editor Neo provides a number of checksum calculation algorithms. All algorithms are capable of quickly calculating the result for the whole document, or only part of it. All checksum calculation algorithms fully support multiple selection.

The following section, Checksum Tool Window, describes the user interface window used to configure and start checksum calculation. Below is a complete list of supported algorithms.

Simple summators

This section contains the following algorithms: 8-bit sum, 16-bit sum and 32-bit sum. It treats the document (or selection) as a stream of unsigned bytes and computes the sum of them. A summator is sized according to the selected algorithm and overflow may occur during calculation.

More summators

This section contains the algorithms that treat the document as a stream of 8, 16, 32 or 64-bit unsigned little-endian or big-endian numbers. Each algorithm calculates the simple 64-bit sum of all values.

Signed sums

This section has the same algorithms as in previous section, but each algorithm now operates on signed numbers.

Checksum

The following algorithms are supported:

Algorithm	Notes
CRC-16	Cyclic redundancy check. CRC polynomial: x16 + x15 + x2 + 1. Used in XMODEM, USB, many others.
CRC-16 (CRC-CCITT)	Cyclic redundancy check. CRC polynomial: x16 + x12 + x5 + 1. Used in X.25, V.41, Bluetooth, PPP, IrDA, BACnet
CRC-32	Cyclic redundancy check. CRC polynomial: x32 + x26 + x23 + x22 + x16 + x12 + x11 + x10 + x8 + x7 + x5 + x4 + x2 + x + 1. Used in V.42, MPEG-2.
CRC XMODEM	Cyclic redundancy check. CRC polynomial: x16 + x12 + x5 + 1. Used in XMODEM.
Custom CRC	Allows you to specify the polynomial values used in checksum calculation. See the Configuring Custom CRC section for more information.
Adler-32	Adler-32 checksum. Used in zlib and others.
Fletcher	RFC 1146. Fletcher checksum.

Fowler-Noll-Vo (FNV) Hashes

The following algorithms are supported:

Algorithm	Notes
FNV-1 32-bit	32-bit FNV-1 hash
FNV-1a 32-bit	32-bit FNV-1a hash
FNV-1 64-bit	64-bit FNV-1 hash
FNV-1a 64-bit	64-bit FNV-1a hash
Custom FNV-1	FNV-1(a) hash with custom parameters

Hashes

Note that actual list of algorithms in this section depends on version and localization of operating system. Some of the following algorithms may not be available in old or localized versions of operating system.

Algorithm	Notes
MD2	RFC 1319. Digest size is 128 bits.
MD4	Digest size is 128 bits.
MD5	Digest size is 128 bits.
SHA-1	RFC 3174. Digest size is 128 bits.
SHA-256	Not supported on Windows XP
SHA-384	Not supported on Windows XP
SHA-512	Not supported on Windows XP
RMD-160	RIPEMD-160 (RACE Integrity Primitives Evaluation Message Digest) - 160-bit message digest algorithm.
RMD-128	RIPEMD-128 (RACE Integrity Primitives Evaluation Message Digest) - 128-bit message digest algorithm.