Which command is used to convert a PEM certificate to DER format?

Which command is used to convert a PEM certificate to DER format?

• A. openssl x509 -in cert.pem -out cert.der -outform DER
• B. openssl x509 -in cert.pem -to der -out cert.der
• C. openssl convert -in cert.pem -out cert.der -der
• D. openssl der -in cert.pem -out cert.der

Answer: (A)

The command to convert a PEM certificate to DER format uses the OpenSSL utility, specifically targeting the x509 command to handle the input and output formats correctly. In this case, the correct syntax mentions both the input file in PEM format and the specification of the output format as DER. The inclusion of the `-outform DER` option explicitly instructs OpenSSL to convert the certificate into DER format, which is a binary encoding. This is essential because the tool needs to know how to treat the output, ensuring that the resulting file is properly formatted. The other options utilize incorrect commands or syntax that do not align with OpenSSL's expected format. For instance, some options do not specify the output format clearly, while others suggest using non-existent commands or flags that would not execute successfully within the OpenSSL framework.

The command to convert a PEM certificate to DER format uses the OpenSSL utility, specifically targeting the x509 command to handle the input and output formats correctly. In this case, the correct syntax mentions both the input file in PEM format and the specification of the output format as DER.

The inclusion of the -outform DER option explicitly instructs OpenSSL to convert the certificate into DER format, which is a binary encoding. This is essential because the tool needs to know how to treat the output, ensuring that the resulting file is properly formatted.

The other options utilize incorrect commands or syntax that do not align with OpenSSL's expected format. For instance, some options do not specify the output format clearly, while others suggest using non-existent commands or flags that would not execute successfully within the OpenSSL framework.