Does it work with secret string longer than 10 chars?

[f616]

My base32 string has 52 chars and I've been unable to generate valid tokens. Don't know why. I'm still troubleshooting but would like to know your feedback on this.

[lucadentella]

Hi

Yes, it should be no limit in key length... see for example issue #7 and other closed issues.

[f616]

Hi After reading the closed issues, and now I understand there is no limitations on the number of chars. The problem is that I was generating the hmacKey with the base32 secret instead of using the plain_text.

The issue here is that I do not have the plain_text secret. I only have the base32 encoded. And when I try to decode it (using some online services), it is giving some errors (Error: Decoded data is not valid UTF-8).

Is there any way in your sketch to use the base32 encoded string instead of the plain_text?

https://totp.danhersam.com/#/WW4M3CGAVC76RHXIRY3HONP5PL3WSFDGO3FIZU3IVSQWJISHCEVQ

[lucadentella]

No, but you can use a "base32 to hex" converter to get rid of the decoding problem: https://cryptii.com/pipes/base32-to-hex

and use the resulting byte array as key in the sketch (just remember to append 0x to each byte and separate them with commas):

uint8_t hmacKey[] = {0xb5,0xb8,0xcd,0x88,0xc0,0xa8,0xbf,0xe8,0x9e,0xe8,0x8e,0x36,0x77,0x35,0xfd,0x7a,0xf7,0x69,0x14,0x66,0x76,0xca,0x8c,0xd3,0x68,0xac,0xa1,0x64,0xa2,0x47,0x11,0x2b};

[f616]

Issue solved. I use the https://cryptii.com/pipes/base32 to directly decode the base32 encoded string to HEX, and it worked just fine.

Is there a way to do this decoding directly on the sketch?

[lucadentella]

Good! Closing...

PS: I think you can find a base32 library for arduino that can do the decoding step in you sketch.