The SSL certificates used by the TCP/IP Stack's SSL module are stored in the CustomSSLCert.c source file. The following series of steps describe how to create the structures in CustomSSLCert.c using an SSL certificate.
- Download and install the OpenSSL library. There are several third-party sites that offer SSL installers (e.g.
http://www.slproweb.com/products/Win32OpenSSL.html). Note that some distributions may not include all commands specified by the OpenSSL documentation. - Open a console and change directory to the OpenSSL/bin folder.
- If you don't have a key and certificate, you can generate them first. The following example console commands will generate a a 512-bit key:
- Generate the key: openssl genrsa -out 512bits.key 512
- Generate the Certificate Signing Request (CSR). You will need to add additional information when prompted: openssl req -new -key 512bits.key -out 512bits.csr
- Generate the X.509 certificate if self-signing (or send the CSR to a Certificate Authority for signing): openssl x509 -req -days 365 -in 512bits.csr -signkey 512bits.key -out 512bits.crt (note that if the -days option is not specified, the default expiration time is 30 days)
- For additional documentation, refer to http://www.openssl.org/docs/apps/openssl.html.
- Parse your key file using the command: openssl.exe asn1parse -in "[directory containing your key]\512bits.key"
- You should see a screen like this:
- If you are not using an ENCX24J600 family device, then the last 5 integers displayed here are the SSL_P, SSL_Q, SSL_dP, SSL_dQ, and SSL_qInv parameters, respectively. However, they are displayed here in big-endian format, and the Microchip cryptographic library implementation requires parameters in little-endian format, so you will have to enter the parameters into the C arrays in opposite order. For example, the INTEGER at offset 145:
145:d=1 h1=2 ;= 33 prim: INTEGER :D777566780029FCD610200B66D89507D 915E3E5BDB6FAB0233B5DFA2E4081DF7
will be swapped in the CustomSSLCert.c file:
ROM BYTE SSL_P[] = {
0xF7, 0x1D, 0x08, 0xE4, 0xA2, 0xDF, 0xB5, 0x33,
0x02, 0xAB, 0x6F, 0xDB, 0x5B, 0x3E, 0x5E, 0x91,
0x7D, 0x50, 0x89, 0x6D, 0xB6, 0x00, 0x02, 0x61,
0xCD, 0x9F, 0x02, 0x80, 0x67, 0x56, 0x77, 0xD7
};- If you are using an ENCX24J600 family device, then the second and fourth integers displayed here are the SSL_N and SSL_D parameters, respectively. There is no need to do an endian format change for these parameters. For the example, the expected SSL_N and SSL_D values are shown in the figure below:
- Parse your X.509 certificate using the command: openssl.exe asn1parse -in "[directory containing your cert]\512bits.crt" -out cert.bin
- Open the cert.bin output file in a hex editor. For example, here is the default certificate information generated from 512bits.crt given in the stack:
- This information must be copied verbatim into the SSL_CERT[] array. Note that this is binary data (not a large integer) so it does not get endian-swapped like the private key parameters.
ROM BYTE SSL_CERT[524] = {
0x30, 0x82, 0x02, 0x08, 0x30, 0x82, 0x01, 0xb2, 0x02, 0x09, 0x00, 0xa5, 0x6a, 0xea, 0x1a, 0xa9,
0x52, 0x9d, 0x1e, 0x30, 0x0d, 0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01, 0x05,
0x05, 0x00, 0x30, 0x81, 0x8a, 0x31, 0x0b, 0x30, 0x09, 0x06, 0x03, 0x55, 0x04, 0x06, 0x13, 0x02,
0x55, 0x53, 0x31, 0x10, 0x30, 0x0e, 0x06, 0x03, 0x55, 0x04, 0x08, 0x13, 0x07, 0x41, 0x72, 0x69,
0x7a, 0x6f, 0x6e, 0x61, 0x31, 0x11, 0x30, 0x0f, 0x06, 0x03, 0x55, 0x04, 0x07, 0x13, 0x08, 0x43,
0x68, 0x61, 0x6e, 0x64, 0x6c, 0x65, 0x72, 0x31, 0x23, 0x30, 0x21, 0x06, 0x03, 0x55, 0x04, 0x0a,
0x13, 0x1a, 0x4d, 0x69, 0x63, 0x72, 0x6f, 0x63, 0x68, 0x69, 0x70, 0x20, 0x54, 0x65, 0x63, 0x68,
0x6e, 0x6f, 0x6c, 0x6f, 0x67, 0x79, 0x2c, 0x20, 0x49, 0x6e, 0x63, 0x2e, 0x31, 0x1d, 0x30, 0x1b,
0x06, 0x03, 0x55, 0x04, 0x0b, 0x13, 0x14, 0x53, 0x53, 0x4c, 0x20, 0x44, 0x65, 0x6d, 0x6f, 0x20,
0x43, 0x65, 0x72, 0x74, 0x69, 0x66, 0x69, 0x63, 0x61, 0x74, 0x65, 0x31, 0x12, 0x30, 0x10, 0x06,
0x03, 0x55, 0x04, 0x03, 0x13, 0x09, 0x6d, 0x63, 0x68, 0x70, 0x62, 0x6f, 0x61, 0x72, 0x64, 0x30,
0x1e, 0x17, 0x0d, 0x30, 0x37, 0x31, 0x30, 0x30, 0x39, 0x31, 0x38, 0x33, 0x37, 0x32, 0x37, 0x5a,
0x17, 0x0d, 0x31, 0x37, 0x31, 0x30, 0x30, 0x36, 0x31, 0x38, 0x33, 0x37, 0x32, 0x37, 0x5a, 0x30,
0x81, 0x8a, 0x31, 0x0b, 0x30, 0x09, 0x06, 0x03, 0x55, 0x04, 0x06, 0x13, 0x02, 0x55, 0x53, 0x31,
0x10, 0x30, 0x0e, 0x06, 0x03, 0x55, 0x04, 0x08, 0x13, 0x07, 0x41, 0x72, 0x69, 0x7a, 0x6f, 0x6e,
0x61, 0x31, 0x11, 0x30, 0x0f, 0x06, 0x03, 0x55, 0x04, 0x07, 0x13, 0x08, 0x43, 0x68, 0x61, 0x6e,
0x64, 0x6c, 0x65, 0x72, 0x31, 0x23, 0x30, 0x21, 0x06, 0x03, 0x55, 0x04, 0x0a, 0x13, 0x1a, 0x4d,
0x69, 0x63, 0x72, 0x6f, 0x63, 0x68, 0x69, 0x70, 0x20, 0x54, 0x65, 0x63, 0x68, 0x6e, 0x6f, 0x6c,
0x6f, 0x67, 0x79, 0x2c, 0x20, 0x49, 0x6e, 0x63, 0x2e, 0x31, 0x1d, 0x30, 0x1b, 0x06, 0x03, 0x55,
0x04, 0x0b, 0x13, 0x14, 0x53, 0x53, 0x4c, 0x20, 0x44, 0x65, 0x6d, 0x6f, 0x20, 0x43, 0x65, 0x72,
0x74, 0x69, 0x66, 0x69, 0x63, 0x61, 0x74, 0x65, 0x31, 0x12, 0x30, 0x10, 0x06, 0x03, 0x55, 0x04,
0x03, 0x13, 0x09, 0x6d, 0x63, 0x68, 0x70, 0x62, 0x6f, 0x61, 0x72, 0x64, 0x30, 0x5c, 0x30, 0x0d,
0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01, 0x01, 0x05, 0x00, 0x03, 0x4b, 0x00,
0x30, 0x48, 0x02, 0x41, 0x00, 0xaa, 0x96, 0xca, 0x97, 0xea, 0x27, 0xb0, 0xd7, 0xe9, 0x21, 0xd0,
0x40, 0xd4, 0x2c, 0x09, 0x5a, 0x2e, 0x3a, 0xe4, 0x12, 0x64, 0x2d, 0x4b, 0x1b, 0x92, 0xdf, 0x79,
0x68, 0x4e, 0x3c, 0x51, 0xf4, 0x43, 0x48, 0x0d, 0xf2, 0xc8, 0x50, 0x9b, 0x6e, 0xe5, 0xea, 0xfe,
0xef, 0xd9, 0x10, 0x41, 0x08, 0x14, 0xf9, 0x85, 0x49, 0xfc, 0x50, 0xd3, 0x57, 0x34, 0xdc, 0x3a,
0x0d, 0x79, 0xf8, 0xd3, 0x99, 0x02, 0x03, 0x01, 0x00, 0x01, 0x30, 0x0d, 0x06, 0x09, 0x2a, 0x86,
0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01, 0x05, 0x05, 0x00, 0x03, 0x41, 0x00, 0x18, 0x18, 0xfe, 0x8b,
0x2d, 0x0d, 0xf7, 0x0d, 0x65, 0x9d, 0x29, 0xec, 0xb3, 0x51, 0x6e, 0x3b, 0x93, 0xbb, 0x40, 0x1a,
0x0b, 0x34, 0x07, 0x63, 0x5e, 0x6a, 0x1c, 0x74, 0x59, 0xd4, 0x54, 0xd2, 0x1b, 0xf3, 0x31, 0xb7,
0x57, 0x4b, 0xa5, 0xe6, 0xe2, 0x35, 0xf7, 0xb3, 0x6a, 0x15, 0x6e, 0x3c, 0x93, 0x85, 0xb2, 0xca,
0xf5, 0x35, 0x00, 0xf4, 0x49, 0xe7, 0x00, 0x8a, 0x00, 0xd8, 0xe8, 0xcf
};- Update the SSL_CERT_LEN variable to contain the correct value.
Module