61 lines
2.3 KiB
Markdown
61 lines
2.3 KiB
Markdown
From https://github.com/pratikd650/Teensy_U2F/blob/master/Teensy_U2F.cpp line 292
|
|
|
|
Instructions to generate attestation certificate using open ssl
|
|
https://wiki.openssl.org/index.php/Command_Line_Elliptic_Curve_Operations
|
|
https://www.guyrutenberg.com/2013/12/28/creating-self-signed-ecdsa-ssl-certificate-using-openssl/
|
|
P-256 (also secp256r1) EC key pair is W = dG (Note secp256k1 is Koblitz curve - not P256)
|
|
d = private key is it 256 bits (32 bytes)
|
|
G = generator point - it is part of the curve definition
|
|
W = public key point - it is a (256, 256) bits - 64 bytes
|
|
1) Generate a key pair - the private key will be saved in PKCS8 format in ecprivkey.pem
|
|
|
|
`openssl ecparam -name prime256v1 -genkey -noout -out ecprivkey.pem`
|
|
|
|
2) Dump out the private key in hex format - it will be a 32 byte key
|
|
|
|
`openssl asn1parse -in ecprivkey.pem`
|
|
|
|
3) Compute the public key from the private key and the curve
|
|
|
|
`openssl ec -in ecprivkey.pem -pubout -out ecpubkey.pem`
|
|
|
|
4) Dump out the public key in hex format - it will be 66 byte - the first two bytes are 00 04,
|
|
|
|
`openssl ec -in ecprivkey.pem -pubout -text`
|
|
|
|
after that is the point W - 32 byte + 32 byte
|
|
|
|
5) Generate a self signed certificate
|
|
|
|
`openssl req -new -x509 -key ecprivkey.pem -out certificate.pem -days 3650`
|
|
|
|
For the Certificate name give a unique certificate name.
|
|
|
|
6) Display the certificate
|
|
|
|
`openssl x509 -in certificate.pem -text -noout`
|
|
|
|
7) Convert PEM certificate to DER
|
|
|
|
`openssl x509 -outform der -in certificate.pem -out certificate.der`
|
|
|
|
8) Generate a usable c-array for source code
|
|
|
|
`xxd --include certificate.der`
|
|
|
|
Copy output into appropriate array in 'Certificates.cpp', overwriting existing values
|
|
|
|
9) Repeat steps 7 & 8 for public key and private key
|
|
|
|
So:
|
|
|
|
```
|
|
openssl asn1parse -in ecprivkey.pem 2>/dev/null | grep 'HEX DUMP' | perl -pe 's/^.*\[HEX DUMP\]:(.+)$/$1/' 2>/dev/null | xxd -r -p > privkey.der && xxd --include privkey.der
|
|
|
|
openssl ec -in ecprivkey.pem -pubout -text 2>/dev/null | perl -0777 -ne 'print /pub:.+ASN1/sg' 2>/dev/null | sed -e '/pub:/d;/ASN1/d' | perl -pe 's/^\s+(.+):?$/$1/gm' 2>/dev/null | perl -pe 's/\n//' 2>/dev/null | perl -pe 's/(.{2}):?/$1/g' 2>/dev/null | xxd -r -p > pubkey.der && xxd --include pubkey.der
|
|
```
|
|
|
|
and copy the arrays into the correct arrays in Certificates.cpp.
|
|
|
|
If any arrays have different lengths than shown in Certificates.hpp, update these too.
|