Question

Is there a way to extract modulus and exponent of a private key using openssl? If there is a way, please let me know.

Answer 1

Yes. Using the -text option to openssl rsa is one way:

$ openssl genrsa 2048 > dummy.key
Generating RSA private key, 2048 bit long modulus
..............+++
....................+++
e is 65537 (0x10001)
$ openssl rsa -in dummy.key -noout -text
Private-Key: (2048 bit)
modulus:
    00:c3:21:46:32:f5:d8:89:c5:bb:bd:a7:4a:14:32:
    [...]
    ea:5d:d3:20:bd:d7:5d:36:1e:45:28:f3:e3:dd:0b:
    d1:f9
publicExponent: 65537 (0x10001)
privateExponent:
    55:4d:74:8c:ce:a0:cd:09:de:1a:f8:c9:0f:af:4f:
    ed:a1:92:89:89:86:4f:cb:b2:f6:aa:60:e7:05:a6:
    [...]