I make a CA certificate for JITR using BouncyCastle lib in the android app as the below example And a device certificate is generated by this certificate in mbed_tls. At this time, JITR is not working. Namely, a device certificate is not registered in AWS. But In the case of making a ca certificate using OPENSSL, JITR works normally. Below is CA certificate based BouncyCastle lib.

-----BEGIN CERTIFICATE-----

MIIB8jCCAZegAwIBAgIVAK0ct2HFXVdS/k2NblxYGoxyuabfMAoGCCqGSM49BAMC

MDIxCzAJBgNVBAYTAktSMRAwDgYDVQQKDAdUcnVzdEZpMREwDwYDVQQDDAhtZWdh

em9uZTAeFw0yMDEwMjcwMDAwMDBaFw0zNTAxMDEwMDAwMDBaMDIxCzAJBgNVBAYT

AktSMRAwDgYDVQQKDAdUcnVzdEZpMREwDwYDVQQDDAhtZWdhem9uZTBZMBMGByqG

SM49AgEGCCqGSM49AwEHA0IABEknYdqI3CdVlmMkTmqKS63HnHc5PbyBff1RokGG

6NE6z31ilA8Yt2fGFHIln1kQtx//6stBA1bIqiqsSo8wad6jgYkwgYYwHQYDVR0O

BBYEFBHaQtHvagaDPkpWxQurErTekm2cMB8GA1UdIwQYMBaAFBHaQtHvagaDPkpW

xQurErTekm2cMA8GA1UdEwEB/wQFMAMBAf8wEQYJYIZIAYb4QgEBBAQDAgAHMAsG

A1UdDwQEAwIBBjATBgNVHSUEDDAKBggrBgEFBQcDAzAKBggqhkjOPQQDAgNJADBG

AiEA9HSXn3FpGUYLagsI3qaHz3VicMSuADUz/QBYEKN9STkCIQC+8BX/TPADpPOy

ClmBIkjxdDt0Fh7HTDn9UwBUxYA3/g==

-----END CERTIFICATE-----

-----BEGIN EC PRIVATE KEY-----

MIGTAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBHkwdwIBAQQgU9pUZUfplZyhC+mH

Pt8pthLItdpbJ+Qy47r7gJKTNvCgCgYIKoZIzj0DAQehRANCAARJJ2HaiNwnVZZj

JE5qikutx5x3OT28gX39UaJBhujROs99YpQPGLdnxhRyJZ9ZELcf/+rLQQNWyKoq

rEqPMGne

-----END EC PRIVATE KEY-----

BRs.

Hyunung Park