Class ArkadeScriptNum

Namespace

NArk.Arkade.Scripts

Assembly

NArk.Arkade.dll

Sign-magnitude little-endian encoder/decoder for ArkadeScript numeric pushes, matching Bitcoin Script's standard CScriptNum serialization rules but without the 4-byte (or 8-byte) range cap.

public static class ArkadeScriptNum

Inheritance

object

ArkadeScriptNum

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Remarks

ArkadeScript opcodes such as OP_ECMULSCALARVERIFY and OP_TWEAKVERIFY push 32-byte EC scalars on the stack — these don't fit in a 64-bit integer, so the existing internal NArk.Core.Helpers.CScriptNum (which is long-backed) can't be reused directly. This helper covers the wider range while staying byte- compatible with CScriptNum for values that DO fit in a long.

Encoding rules (Bitcoin CScriptNum::serialize):

• Zero is encoded as the empty byte array.
• Non-zero values are written little-endian. The high bit of the most significant byte is reserved for the sign — 1 = negative, 0 = positive. If the value's natural top bit is already 1, an extra byte is appended to carry the sign and avoid ambiguity.
• Decoding is the reverse: an empty array decodes to zero; otherwise the high bit of the last byte is the sign and the remaining bits form the magnitude.

Mirrors the ts-sdk's reliance on @scure/btc-signer's ScriptNum() serializer, including its 520-byte cap (MaxBytes = MaxScriptElementSize); vectors must round-trip 1:1 across SDKs.

Fields

MaxBytes

Maximum encoded length in bytes (= Bitcoin's MaxScriptElementSize).

public const int MaxBytes = 520

Field Value

int

Methods

Decode(ReadOnlySpan<byte>, bool)

Decode a Bitcoin sign-magnitude LE byte array to a BigInteger. Empty input decodes to zero. Throws if requireMinimal is true and the encoding has a redundant zero byte / sign byte, or if the input exceeds MaxBytes bytes.

public static BigInteger Decode(ReadOnlySpan<byte> bytes, bool requireMinimal = true)

Parameters

bytes ReadOnlySpan<byte>

requireMinimal bool

Returns

BigInteger

Exceptions

ArgumentException

bytes exceeds MaxBytes bytes.

Encode(BigInteger)

Encode a BigInteger using Bitcoin sign-magnitude LE.

public static byte[] Encode(BigInteger value)

Parameters

value BigInteger

Returns

byte[]

Exceptions

ArgumentException

The encoded value would exceed MaxBytes bytes.