Document signature and public key formats

[psiemens]

Context

We should document the byte format used for signatures and public keys, both of which are specified in raw form (without metadata).

Definition of Done

• Developers should be be able to see a description of the signature and public key formats used by Flow, and use this definition to implement Flow-compatible cryptographic functions in a variety of languages.

References

• flow-go/crypto signature serialization: https://github.com/onflow/flow-go/blob/f21d550c6ab04dfdd637dad6480679eb39c9a922/crypto/ecdsa.go#L60-L63
• flow-go/crypto public key serialization: https://github.com/onflow/flow-go/blob/f21d550c6ab04dfdd637dad6480679eb39c9a922/crypto/ecdsa.go#L333-L335
• flow-go/crypto private key serialization: https://github.com/onflow/flow-go/blob/f21d550c6ab04dfdd637dad6480679eb39c9a922/crypto/ecdsa.go#L266-L267

cc @m4ksio @tarakby

[tarakby]

Thanks @psiemens, I've updated the references above to the comments describing the encoding method.

[alxflw]

can this be closed @psiemens?

[tarakby]

Cadence docs do detail the format of cryptographic data. Are there other specific docs you would like me to update @psiemens ? I guess transaction format and account creation?