Ansix923Padding Class

Definition

Namespace: Bodu.Security.Cryptography

Assembly: Bodu.Security.Cryptography.dll

Package: Bodu.Security.Cryptography 1.2.0

Source: Ansix923Padding.cs

Implements the ANSI X.923 padding scheme, which appends N - 1 bytes of value 0x00 followed by a trailing byte holding the padding length N.

public sealed class Ansix923Padding : IPaddingStrategy

Inheritance: object

Ansix923Padding

Implements: IPaddingStrategy

Inherited Members: object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.ReferenceEquals(object, object)

object.ToString()

Extension Methods: ComparableExtensions.AtLeast<T>(T, T, IComparer<T>)

ComparableExtensions.AtMost<T>(T, T, IComparer<T>)

ComparableExtensions.IsEqualTo<T>(T, T, IComparer<T>)

ComparableExtensions.Max<T>(T, T, IComparer<T>)

ComparableExtensions.Min<T>(T, T, IComparer<T>)

Examples

using Bodu.Security.Cryptography;

IPaddingStrategy padding = new Ansix923Padding();
byte[] padded = padding.Pad(plaintext, blockSize: 128); // 128 bits = 16 bytes

// padded ends with N-1 zero bytes followed by a single byte holding N.
byte[] recovered = padding.Unpad(padded, blockSize: 128);

Remarks

A full block of padding is always added when the input is already block-aligned so that Unpad(ReadOnlySpan<byte>, int) can unambiguously recover the original length. Valid values of N lie in the range 1..blockSize. Unpad(ReadOnlySpan<byte>, int) validates in constant time to resist padding-oracle side channels.

When to choose ANSI X.923. Pick this when interoperating with legacy financial / banking systems or formats that explicitly require the X.923 layout. For all other cases use Pkcs7Padding - it is the modern standard and is what every mainstream library expects by default.

Constructors