Topic: Public Key / Private Key Format.


I our project, we have two embedded hardware (STM32F4) based modules. In Module-1  we are using wolfSSL library and in Module-2 we are using Atmel's cryptoAuthLib. We are finding some interoperability issue in the public key size format. The public key generated in the wolfSSL is 91 Byte size and Public key generated by ATECC508 is 64 Bytes. Can you please help me in converting the format of public Key and Private key, ie from 91 byte format to 64 byte format or vice versa.

Thanks and regards,
Manoj Chandran R


Re: Public Key / Private Key Format.

Hi Manoj,

Can you send us examples of the two public keys?  Looking at them may give us some clues as to the difference in formats.


Re: Public Key / Private Key Format.

Hi Chris,

i could solve the issue. It was the header bytes.

0x30, 0x59, 0x30, 0x13, 0x06, 0x07, 0x2A, 0x86,
0x48, 0xCE, 0x3D, 0x02, 0x01, 0x06, 0x08, 0x2A,
0x86, 0x48, 0xCE, 0x3D, 0x03, 0x01, 0x07, 0x03,
0x42, 0x00, 0x04,

The above bytes where header and the below was the key - 64 byte.

0xC4, 0xFA, 0x2F, 0xB4, 0x67,
0x1B, 0xCF, 0x52, 0x71, 0xB6, 0x4C, 0x8D, 0xC2,
0x98, 0x03, 0x48, 0x5E, 0xE9, 0x74, 0x43, 0xB1,
0x99, 0xFC, 0x55, 0xFD, 0x40, 0x58, 0x17, 0xA7,
0x67, 0x65, 0xA4, 0x1B, 0xE1, 0x34, 0xFA, 0xB6,
0xE0, 0xC1, 0xAA, 0x2A, 0xC8, 0x01, 0xF3, 0xD7,
0xC7, 0x41, 0xCD, 0xB7, 0x67, 0x77, 0x62, 0x7D,
0x97, 0x0F, 0x0B, 0xB6, 0xC5, 0xE8, 0x0F, 0xB3,
0xB1, 0x1E, 0xAB,

Thanks and regards,