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.

XOR

Exclusive-OR sums. Has 8-bit, 16-bit, 32-bit and 64-bit variants.

Checksum

Contains CRC (cyclic redundancy check) algorithms:

Algorithm	Bits	Polynomial	Initial	XOR Out	Reflection IN	Reflection Out	Notes
CRC-16	16	0x8005	0	0	Y	Y	Cyclic redundancy check. CRC polynomial: x16 + x15 + x2 + 1. Used in XMODEM, USB, many others.
CRC-16 (CRC-CCITT)	16	0x1021	0xFFFF	0	N	N	Cyclic redundancy check. CRC polynomial: x16 + x12 + x5 + 1. Used in X.25, V.41, Bluetooth, PPP, IrDA, BACnet
CRC-32	32	0x04C11DB7	0xFFFFFFFF	0xFFFFFFFF	Y	Y	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	32	0x8408	0	0	Y	Y	Cyclic redundancy check. CRC polynomial: x16 + x12 + x5 + 1. Used in XMODEM.
CRC-64	64	0x42F0E1EBA9EA3693	0	0	N	N	Cyclic redundancy check. CRC polynomial: x64 + x62 + x57 + x55 + x54 + x53 + x52 + x47 + x46 + x45 + x40 + x39 + x38 + x37 + x35 + x33 + x32 + x31 + x29 + x27 + x24 + x23 + x22 + x21 + x19 + x17 + x13 + x12 + x10 + x9 + x7 + x4 + x+1. ECMA-182, XZ Utils
CRC-64/WE	64	0x42F0E1EBA9EA3693	0xFFFFFFF'FFFFFFFFF	0xFFFFFFF'FFFFFFFFF	N	N	Same as CRC-64 but with initial remainder and output XOR set to 0xFFFFFFF'FFFFFFFFF.
CRC-64/XZ	64	0x42F0E1EBA9EA3693	0xFFFFFFF'FFFFFFFFF	0xFFFFFFF'FFFFFFFFF	Y	Y	Same as CRC-64/WE but with initial and output reflections.
Custom CRC							Allows you to specify the polynomial values used in checksum calculation. See the Configuring Custom CRC section for more information.

Additionally, the following checksum algorithms are supported:

Algorithm	Notes
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

xxHash Family Hashes

The following algorithms are supports:

Algorithm	Notes
xxHash32	32-bit xxHash
xxHash64	64-bit xxHash
xxHash3	64-bit xxHash3
xxHash128	128-bit xxHash

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.
BLAKE2s	BLAKE2 cryptographic hash function (BLAKE2s variant)
BLAKE2b	BLAKE2 cryptographic hash function (BLAKE2b variant)
BLAKE3	BLAKE3 cryptographic hash function