Skip to content

Addressing

  • Reed-Solomon (RS) Address Format
  • QR Codes for RS Address Format

Reed-Solomon (RS) Address Format In IEP software, the use of Reed-Solomon addresses for XIN account is supported. It’s the default format in the official client.This form of address improves reliability by introducing redundancy that can detect and correct errors when entering and using XIN account numbers. These addresses are always in the form of:

XIN-xxxx-xxxx-xxxx-xxxx

where x is a non-ambiguous number or alphabetic character (the letters O and I are not used; nor are the numbers 1 and 0). Addresses are always prefixed with “XIN-“, and hyphens are used to separate the address into groups of 4, 4, 4, and then 5 characters. The addresses are NOT case-sensitive.

The default format for XIN account numbers is a completely numeric 64-bit identifier that is derived from the account’s private key. Other options were explored (MD5 hashes, checksum digits, etc.) but a Reed-Solomon format was chosen because:

  • the account collision rate is the same as the default address format;
  • the system’s basic error correction can be used to assist users in typing addresses;
  • some programming languages do not have a native MD5 hashing function, and the Reed-Solomon implementation is simpler than MD5.

Benefits of Reed-Solomon addresses : * The chance of a random address collision, using IEP’s implementation of 4 “check-bits”, is 1 in a million (20-bit redundancy). * It allows up to 2 typos in an address to be corrected. * It guarantees that up to 4 typos can be detected. * The address length is always 17 characters, and is always prefixed with “XIN”. This makes the addresses easily recognizable as belonging to Xin.

Encoding of IEP Reed-Solomon addresses : Case is not enforced in this format, but for unification all addresses are displayed using upper case. Addresses are split by dashes into groups of 4 characters and a final group of 5 characters, but this is not enforced during address input. The old numeric addresses are also recognized and supported for backwards compatibility.

Example RS Addresses:

XIN-K4G1-FF37-QBGTL-6LPSE
XIN-DSAE-3DH4-WLL3-4WQ9

Technical Details The first and most important rule is that no error-correction scheme is infallible: You cannot rely on error correction, period.

The problem is somewhat counter-intuitive: either you can do a simple yes/no check of address validity, which will give you one in a million collision, or you can try and correct errors. You cannot do both.

The problem here is that the Reed-Solomon algorithm is only guaranteed to correct up to 2 errors. If there are more than 2 errors present in an address entry, it will produce false positives with a probability of around 10% and transactions will still be sent to incorrect addresses.

Think of the algorithm as error-guessing, instead, to assist users with spotting errors.

Reed-Solomon (RS) addresses for XIN are encoded as follows: * Take the original 64-bit account ID, add 1 zero bit to get 65 and then split it into thirteen 5-bit “symbols” (65 / 5 = 13). * Order the symbols from lowest bit to highest bits, in little-endian order, i.e. bits 0-4, 5-9, 10-14, etc. up to 60-64. * Append 4 symbols of parity (20 bits), produced by the Reed-Solomon encoding of our 13 symbols from step one (which are left untouched). This produces a 13 + 4 = 17 symbol codeword. * Scramble the code-word symbols in a predefined order and encode them 1-to-1 with an alphabet of 32 characters, splitting them into groups by dashes.

QR Codes for RS Address Format IEP provide few APIs for QR code,

Decode QR Code : Decodes a base64-encoded jpeg to a UTF-8 string.

Request:

http://localhost:23457/api?
requestType=decodeQRCode&
qrCodeBase64=/9j/4AAQSkZJRgABAgAAAQABAAD/2wBDAAgGBgcGBQgHBwcJCQgKDBQNDAsLDBkSEw8UHRo...

Response:

{
"qrCodeData": "XIN-LHG8-88PJ-A5K9-2NRMB",
"requestProcessingTime": 10
}

Encode QR Code : Encodes a UTF-8 string to a base64-encoded jpeg.

Request:

http://localhost:23457/api?requestType=encodeQRCode&qrCodeData=XIN-LHG8-88PJ-A5K9-2NRMB&width=100&height=100

Response:

{
"qrCodeBase64": "/9j/4AAQSkZJRgABAgAAAQABAAD/2wBDAAgGBgcGBQgHBwcJCQgKDBQNDAsLDBkSEw8UH...",
"requestProcessingTime": 10
}