Class ChecksumCRC32

CRC-32 checksum algorithm implementation using the standard IEEE 802.3 generator polynomial. Produces the same 32-bit result as the CRC used in Ethernet, GZip, ZIP, PNG, and many other widespread formats.

Inheritance

object

ChecksumCRC32

Implements

IChecksum

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: Scylla.Core.Util.Checksum

Assembly: ScyllaCore.dll

Syntax

public sealed class ChecksumCRC32 : IChecksum

Remarks

Algorithm details:

• Polynomial (reflected representation): 0xEDB88320, which is the bit-reversal of the normal form 0x04C11DB7 (IEEE 802.3).
• Initial value: 0xFFFFFFFF (all ones).
• Input / output reflection: reflected (least-significant bit first).
• Final XOR: 0xFFFFFFFF, applied automatically in Value.
• Output width: 32 bits.

Lookup-table acceleration is used: the 256-entry table is computed once at class initialisation and shared across all instances via a static field.

Common use cases:

• File integrity verification (ZIP, GZip, PNG checksums).
• Data transmission and networking error detection (Ethernet IEEE 802.3).
• Save game and asset cache validation.
• Any situation requiring a well-known, interoperable 32-bit checksum.

Comparison with other algorithms: CRC-32 offers strong error detection for all single-bit, double-bit, odd-count bit errors, and burst errors up to 32 bits. It is somewhat slower than ChecksumAdler32 but more reliable for short messages. For very high throughput requirements on 64-bit platforms, consider ChecksumXXHash64.

Security note: CRC-32 is NOT cryptographically secure. For security-sensitive hashing use the Scylla Crypto module instead.

Properties

Value

Gets the current CRC-32 checksum value with the standard final XOR applied.

Declaration

public long Value { get; }

Property Value

Type	Description
long	A non-negative long in the range [0, 0xFFFF_FFFF]. The internal register is XORed with 0xFFFFFFFF before being returned, matching the IEEE 802.3 and GZip/ZIP CRC-32 convention. Returns 0 (i.e., 0xFFFFFFFF ^ 0xFFFFFFFF) when no data has been processed.

Methods

Reset()

Resets the CRC-32 checksum to its standard initial state (internal register = 0xFFFFFFFF), discarding any previously processed data.

Declaration

public void Reset()

Remarks

After calling Reset, Value returns 0 (the result of 0xFFFFFFFF ^ 0xFFFFFFFF). Subsequent Update(byte[]) calls begin a fresh CRC computation. Use this to reuse the same instance for multiple independent checksums without allocating a new object.

Update(byte[])

Updates the CRC-32 checksum by incorporating all bytes in buffer.

Declaration

public void Update(byte[] buffer)

Parameters

Type	Name	Description
byte[]	buffer	The byte array to process. If null or empty, the call is a no-op and the checksum state is unchanged.

Update(byte[], int, int)

Updates the CRC-32 checksum by incorporating count bytes from buffer starting at offset.

Declaration

public void Update(byte[] buffer, int offset, int count)

Parameters

Type	Name	Description
byte[]	buffer	The source byte array. If null, or if count is zero, the call is a no-op.
int	offset	Zero-based index of the first byte to read in buffer.
int	count	Number of bytes to process. Must not cause offset + count to exceed buffer.Length.

Remarks

Each byte is processed with a single table lookup: _crc = table[(_crc ^ byte) & 0xFF] ^ (_crc >> 8). Multiple calls accumulate into the same CRC register; the final result is equivalent to processing the entire concatenated input in a single call.

Implements

IChecksum

Extension Methods

FileExtensions.SaveSecureToFileAsync<T>(T, string, string, CancellationToken)

FileExtensions.SaveSecureToFile<T>(T, string, string)

FileExtensions.SaveToFileAsync<T>(T, string, CancellationToken)

FileExtensions.SaveToFile<T>(T, string)

FileExtensions.SaveToFile<T>(T, string, SerializationSettings)

See Also

IChecksum

ChecksumAdler32

ChecksumXXHash32