📅 Original date posted:2015-02-26
📝 Original message:On 02/26/2015 12:14 PM, Oleg Andreev wrote:
>
>> Base43 is the same as any BaseX standard, but using a different alphabet
>> (43 characters). It's meant to be used for efficiently storing binary
>> data into QR codes. The alphabet is picked to match the 'Alphanumeric'
>> input mode of QR codes as closely as possible, but at the same time be
>> allowed in URIs.
>
> Does it mean Base58 or Base64 take more space in QR code than Base43? Do you have an estimate of the gains?
Both Base58 and Base64 force QR codes into binary encoding. Base64 can
take 6 bits per char, binary of course has 8 bits per char. So you're
wasting 25% of space if you use Base64, a little bit more with Base58.
Base43 takes log2(43) = 5.43 bits per char, while each char uses up 5.5
bits in QR codes in 'Alphanumeric' encoding. So that's a waste of 1.3%.
Source for QR code standard: http://en.wikipedia.org/wiki/QR_code
Andreas Schildbach [ARCHIVE] /
npub1xg…adsv7
2023-06-07 15:31:22
in reply to nevent1q…yjnk
Author Public Key
npub1xg2m84malu0cfm4444r0kysx4rgk27e75aj6sz6538kw8fcz627qeadsv7Published at
2023-06-07 15:31:22Event JSON
{
"id": "17d968bb322f7cb96eb93d101393cbc151df8318d762104fb24454639edfea68",
"pubkey": "3215b3d77dff1f84eeb5ad46fb1206a8d1657b3ea765a80b5489ece3a702d2bc",
"created_at": 1686151882,
"kind": 1,
"tags": [
[
"e",
"c6af91f24b3981cdcac6f1b71f0c3aa87d0893860f8efd2742c85eb40ee7ecc4",
"",
"root"
],
[
"e",
"04ff49092aa0de6a192546eb23b9a4c7f99c91bd9bfb827ac95b30f1f500f784",
"",
"reply"
],
[
"p",
"8a620b25e89444e9903ffc62514250941ca318d3dd371308821b4cbe30dd482a"
]
],
"content": "📅 Original date posted:2015-02-26\n📝 Original message:On 02/26/2015 12:14 PM, Oleg Andreev wrote:\n\u003e \n\u003e\u003e Base43 is the same as any BaseX standard, but using a different alphabet\n\u003e\u003e (43 characters). It's meant to be used for efficiently storing binary\n\u003e\u003e data into QR codes. The alphabet is picked to match the 'Alphanumeric'\n\u003e\u003e input mode of QR codes as closely as possible, but at the same time be\n\u003e\u003e allowed in URIs.\n\u003e \n\u003e Does it mean Base58 or Base64 take more space in QR code than Base43? Do you have an estimate of the gains? \n\nBoth Base58 and Base64 force QR codes into binary encoding. Base64 can\ntake 6 bits per char, binary of course has 8 bits per char. So you're\nwasting 25% of space if you use Base64, a little bit more with Base58.\n\nBase43 takes log2(43) = 5.43 bits per char, while each char uses up 5.5\nbits in QR codes in 'Alphanumeric' encoding. So that's a waste of 1.3%.\n\nSource for QR code standard: http://en.wikipedia.org/wiki/QR_code",
"sig": "45c516d54d0c15a9ced6af67a2cfd5d3f709152f5528321d1abf237f6f437a3a1408bed88a3f39a2b86613607a13f193daecf830afd7922771bbb198dceecf0f"
}