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Decoded

Base45
Base45/Zlib/COSE/CBOR

Encoded

Base45

About Base45

Base45 is an encoding scheme that uses 7-bit printable ASCII characters.

Base45 divides the data into two bytes each and converts them into three ASCII characters to represent them.

The ASCII characters used in Base45 are as follows: treat the 2-byte value as a big-endian unsigned integer, calculate each digit (3 digits) of the 45 decimal system, and then calculate the Base45 conversion result based on the following ASCII characters.

45 decimal digitsBase45 ASCII characters
00
11
22
33
44
55
66
77
88
99
10A
11B
12C
13D
14E
15F
16G
17H
18I
19J
20K
21L
22M
23N
24O
25P
26Q
27R
28S
29T
30U
31V
32W
33X
34Y
35Z
36 [SP]
37$
38%
39*
40+
41-
42.
43/

For example, if you convert "Hello" with Base45, it will look like this.

1. Separate every 2 bytes.

4865(16) 6C6C(16) 6F(16)  (He ll o)

2. Every 2 bytes are treated as a big-endian unsigned integer, and the value is converted to 3 digits in each of the 45 decimal systems. If the end is a single byte, it is converted to 2 digits of the 45 decimal system.

4865(16)
= 18533(10)
= 9 * 452 + 6 * 45 + 38
6C6C(16)
= 27756(10)
= 13 * 452 + 31 * 45 + 36
6F(16)
= 111(10)
= 2 * 45 + 21

3. Convert each 3 digits of the 45 decimal system to ASCII characters in reverse order.

45 decimal digits3869363113212
Base45 ASCII characters%69 [SP]VDL2

4. The characters are all connected to form the result of the Base45 conversion.

%69 VDL2

About Base45/Zlib/COSE/CBOR

Base45/Zlib/COSE/CBOR is CBOR format data signed in COSE format, compressed in Zlib format, and converted to Base45 format.

EUDCC (EU Digital COVID Certificate) is used as the data format for QR codes. EUDCC is the common format for the COVID-19 vaccination certificate in the EU, also known as DGC (EU Digital Green Certificate) or Green Pass.

DenCode supports decoding only, and the decoded result is expressed in JSON format. The validity of the signature is not verified.