BC-UR Uniform Resources implementation offering full encode/decode, rateless fountain codes for animated QR transmission with deterministic PRNG, Bytewords and minimal CBOR, CRC-32/SHA-256, streaming multipart decoding.
Pure Kotlin Multiplatform implementation of BC-UR (Uniform Resources) with full encoder and decoder support, including fountain codes for animated QR transmission.
UREncoder and URDecoder for single and multi-part URsAdd bcur-kotlin as a module in your project:
// settings.gradle.kts
include(":bcur-kotlin")
// app/build.gradle.kts
dependencies {
implementation(project(":bcur-kotlin"))
}
implementation("com.gorunjinian:bcur-kotlin:1.0.5")
import com.gorunjinian.bcur.UR
import com.gorunjinian.bcur.UREncoder
import com.gorunjinian.bcur.Cbor
// Wrap raw PSBT bytes in CBOR byte string
val cborData = Cbor.wrapInByteString(psbtBytes)
val ur = UR("crypto-psbt", cborData)
// Encode to UR string for QR code display
val urString = UREncoder.encode(ur)
// "ur:crypto-psbt/hdosjojkidjyzmad..."
val ur = UR("crypto-psbt", cborData)
val encoder = UREncoder(ur, maxFragmentLen = 150)
// Generate parts in a loop for animated QR display
while (true) {
val part = encoder.nextPart()
displayQrCode(part) // ur:crypto-psbt/1-10/lpadaxcs...
delay(200) // ~5 fps
}
import com.gorunjinian.bcur.UR
import com.gorunjinian.bcur.Cbor
val ur = UR.parse("ur:crypto-psbt/hdosjojkidjyzmad...")
val psbtBytes = Cbor.unwrapByteString(ur.cborData)
import com.gorunjinian.bcur.URDecoder
import com.gorunjinian.bcur.ResultType
val decoder = URDecoder()
// Feed scanned QR parts as they arrive
fun onQrScanned(content: String) {
decoder.receivePart(content)
decoder.result?.let { result ->
if (result.type == ResultType.SUCCESS) {
val ur = result.ur!!
val psbtBytes = Cbor.unwrapByteString(ur.cborData)
// Use psbtBytes
}
}
}
UR (data) --> Bytewords Encoding --> Single-Part UR String
UR (data) --> Fountain Encoder --> Part 1, Part 2, ... Part N
|
Bytewords Encoding
|
Multi-Part UR Strings
Cbor module handles minimal CBOR encoding (byte strings, unsigned integers, arrays) sufficient for the UR transport layer. Full CBOR schema support for BCR-2020-010 (crypto-output) and BCR-2020-015 (crypto-account) — including tagged CBOR descriptors (tag 308 for output descriptors, tag 303 for HD keys, tag 304 for key paths, etc.) — is planned and will be ported soon.Ported from and verified against:
MIT License
| Module | Description |
|---|
UR | Core Uniform Resource data class |
UREncoder | Single and multi-part UR encoding |
URDecoder | Single and multi-part UR decoding (streaming) |
FountainEncoder | Rateless fountain code encoder |
FountainDecoder | Fountain code decoder with XOR reduction |
Bytewords | BCR-2020-012 byte-to-word encoding |
Cbor | Minimal CBOR encode/decode utilities |
CRC32 | Pure Kotlin CRC-32 checksum |
SHA256 | Pure Kotlin SHA-256 hash |
Xoshiro256StarStar | Deterministic PRNG for fountain codes |
Surfaced from shared tags and platforms — no rankings paid for.