R: transforming Crypto++ DER-formatted RSA public key to OpenSSL's PEM format

[Maiorano Gerardo]

Title: transforming Crypto++ DER-formatted RSA public key to OpenSSL's PEM format

Hi, you must try this command on the command-line:

$ openssl rsa -in pub.der -inform DER -pubin -pubout -outform PEM -out pub.pem

-----Messaggio originale-----
Da: Adrian Petru DIMULESCU [mailto:[EMAIL PROTECTED]
Inviato: mercoled� 18 settembre 2002 10.21
A: [EMAIL PROTECTED]
Oggetto: transforming Crypto++ DER-formatted RSA public key to OpenSSL's PEM format

Hello,

I am trying to write a function which transforms a DER-formatted Crypto++ RSA *PUBLIC* key into its OpenSSL PEM counterpart.

I saw some hints on the Crypto++ FAQ this page:

http://www.eskimo.com/~weidai/cgi-bin/fom-serve/cache/62.html

Unfortunately, while it works very well for the *PRIVATE* key, it doesn't seem to be able to convert the PUBLIC one.

Here's what I get from OpenSSL:

$ openssl pkcs8 -in pub.der -inform DER -out pub.pem -nocrypt
Error decrypting key
31109:error:0D080071:asn1 encoding routines:d2i_ASN1_INTEGER:expecting an integer:a_int.c:204:
31109:error:0D0FA004:asn1 encoding routines:d2i_PKCS8_PRIV_KEY_INFO:nested asn1 error:p8_pkey.c:106:address=135556640 offset=3

If you take a look into the error message you will see that apparently OpenSSL tries to transform it as a PRIVATE key, not a public one.

Any idea is of course welcome,
Adrian Petru Dimulescu;



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