Cannot decrypt private key encrypted with passphrase

[longnguyennhnd]

I am trying to generate 1 certificate with 1 public key and 1 private key with the following format

-----BEGIN RSA PRIVATE KEY-----
Proc-Type: 4,ENCRYPTED
DEK-Info: DES-EDE3-CBC,5E39D2DDBA544FDE

3+ptiWruvYHzhX+rpSC3852..............................
-----END RSA PRIVATE KEY-----

But when I run the following code
ICertificateProvider provider = new CertificateFromFileProvider(publicKey, privateKey, false, passpharse);
, it returns an exeption like this:
The input is not a valid Base-64 string as it contains a non-base 64 character, more than two padding characters, or an illegal character among the padding characters.
Looking forward to hearing from you