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<p class="MsoNormal">It is hard to follow this thread with all the indenting.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal" style="margin-bottom:12.0pt">> If I take a PEM-encoded RSA private key file and convert it to binary (using b64decode) what I get is not the same thing as I get from "openssl rsa -inform pem -in key -outform der -out key.der".<br>
<br>
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<p class="MsoNormal" style="margin-bottom:12.0pt">How do you convert it? Did you strip off the ---BEGIN and END tags? Then it absolutely should have been the same thing.<o:p></o:p></p>
<p class="MsoNormal" style="margin-bottom:12.0pt">An internal structure, such as an RSA object, can be converted to DER using d2i_RSA. DER is useful because it is a “flat” format, whereas the internal object is useful in the C code. Make sense? DER files
are useful if you already know what the filetype is. The d2i_ and i2d_ functions convert between internal (C structures, with pointers etc) to DER encoding. They basically work on buffers, only.<o:p></o:p></p>
<p class="MsoNormal" style="margin-bottom:12.0pt">PEM files are base64 encoded DER, with BEGIN and END tags that specify what the middle-part is. It is useful because it is human readable. Also the PEM_read_xxxx functions will check what is expected to what
the file says it is.<o:p></o:p></p>
<p class="MsoNormal" style="margin-bottom:12.0pt">Most objects have PEM_read and PEM_write functions as well. They are not necessarily obvious from scanning the header files, because they are declared and implemented as macro’s, as it’s common code with just
a pointer to an internal description of what the ASN1/DER looks like.<o:p></o:p></p>
<p class="MsoNormal" style="margin-bottom:12.0pt">The documentation on the master branch does a much better, and more complete, job of explaining this.<o:p></o:p></p>
<p class="MsoNormal" style="margin-bottom:12.0pt">The function I think you want is PEM_read_PrivateKey.<o:p></o:p></p>
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