[BUG] IV missing in EMBlock unprotected header for AES_CCM_64_128_128/AES_CCM_64_128_256 ciphersuites

[Sai-Anudeep47]

To simplify issue resolution process, please provide network logs, and or test voucher. csdk_to2_ccm_aesiv_error_log.txt

What part of the spec are you testing?

• [ ] Rendezvous Server
• [x] Device Onboarding Service
• [ ] Device Implementation

What protocol are having issue with?

• [ ] TO0
• [ ] TO1
• [x] TO2

Issue description

• When using AES_CCM_64_128_128/AES_CCM_64_128_256 ciphersuites, conformance owner returns EMBlock without AES IV field in unprotected header in message 65 and client fails with error "COSE_Encrypt0 Unprotected header: Failed to read AESIV Key"
• Observed that at https://github.com/fido-alliance/fdo-fido-conformance-server/blob/main/core/shared/enc.crypto.go#L411 IVBytes are populated based on algInfo.IVLen field but such field is not present for CCM ciphersuites as declared at https://github.com/fido-alliance/fdo-fido-conformance-server/blob/main/core/shared/enc.crypto.go#L111
• According to https://tinyurl.com/coserfc a check can be included for CCM ciphersuites to populate IVBytes with algInfo.NonceLen
• Log is attached for reference that shows empty unprotected header without IV field

[yackermann]

Addressed