Add new schemes for encrypted licenses

[ezekg]

Closes #178.

[ezekg]

After thinking on this more, I want to allow these schemes:

• RSA_2048_ENCRYPT
• RSA_2048_SIGN

[ezekg]

Thinking on this even more, the RSA_2048_SIGN scheme doesn't make a lot of sense, to be honest, because we'd need the raw license key to do the verification. Might still keep it though…

Edit: we should keep it.

[ezekg]

Need to write tests for:

• Providing an expiry during license creation
• RSA_2048_ENCRYPT scheme for policies
• RSA_2048_SIGN scheme for policies
• RSA_2048_ENCRYPT scheme for licenses
• RSA_2048_SIGN scheme for licenses
• Invalid schemes for policies
• Encrypted key validations

[ezekg]

Currently, disallowing a nil encryptionScheme is a breaking change. Need to allow nil and then default to the LEGACY scheme.

[ezekg]

Need to update RSA encryption padding: https://stackoverflow.com/questions/16325057/why-does-rsa-encrypted-text-give-me-different-results-for-the-same-text. Should use OAEP padding.

Nevermind—that's not how RSA works. OAEP isn't available for private key encryption.

[ezekg]

Would be cool to use RSA_PKCS1_PSS_PADDING, but that doesn't seem to be supported in most programming languages, and I'm not sure how to implement directly using OpenSSL (link is to BoringSSL, but OpenSSL is the same AFAIK).

Maybe we should file an issue? See this issue which added support for PSS signing/verification for Ruby's OpenSSL implementation: ruby/openssl#75.

[ezekg]

Rename schemes for easier addition in the future:

• RSA_2048_ENCRYPT -> RSA_2048_PKCS1_ENCRYPT
• RSA_2048_SIGN -> RSA_2048_PKCS1_SIGN

New schemes:

• RSA_2048_PKCS1_PSS_ENCRYPT (OpenSSL doesn't support the verify_restore op for PSS)
• RSA_2048_PKCS1_PSS_SIGN
• RSA_2048_JWT_RS256

To be able to support RSA_2048_PKCS1_PSS_SIGN, we'll need to use latest of this openssl gem instead of the packaged openssl gem that ships with Ruby, since PSS only ships with Ruby >= 2.5.

I've been working on adding RSA_2048_PKCS1_PSS_ENCRYPT to Ruby's openssl gem, but I'm not even sure if OpenSSL supports it from my initial tests; BoringSSL does, however. It's odd that BoringSSL implements private_encypt and public_decrypt with PSS but OpenSSL does not.

I think the above was incorrect docs on BoringSSL's part. PSS does not support encryption.

[ezekg]

Let's also add a JWT encryption scheme, RSA_2048_JWT_RS256.

[ezekg]

Maybe implement Plaseto as well? To supplement JWT. Edit: eh—the Ruby lib seems poorly maintained and I don't want to add the risk.

[ezekg]

I think I want to drop the new signature column and combine that into the key, JWT-style.

E.g.

"{KEY}.{SIGNATURE}"

[ezekg]

And just for future reference, here's what the different encryption schemes look like:

[
  {
    "scheme": "RSA_2048_PKCS1_PSS_SIGN",
    "key": "eyJmb28iOiJiYXIiLCJiYXoiOiJxdXoiLCJyYW5kIjpbNDgsMTAxLDU2LDk5LDQ5LDQ5LDk3LDUzLDU3LDU0LDQ5LDEwMSw1MCw0OSw1Miw1MCwxMDIsMTAyLDQ5LDU0LDUyLDEwMiw1Miw1NSw1Niw1MCw5Nyw0OCw0OSw1Myw1MywxMDFdfQ==.Dqw0N_14L0v-a-cQPkTM_X6_vN-tSoEWEt2Zu5SreeS_-Zn6Fsyr2EwpnOXWkWHhmcPJWSfboCrOjh73y-Q9I3aLbpTg5M_9bQmt2PjwG0l7A7T2PUreAA-8xftK0-_quQchsv73JDhrst8O1oh2dHBs6fB1EPXzKKCyIXKWIniHjEP-nqGGYXUzPQjoMI7JQCySZKtXmgV4rVRoY1E9kxywlc0Lia9OfHH2uDnBPjIpR_4U_QFLzoUKZnG5qmTC9PtgGbdsN5e01hk53ZvDA9sEdzUerk_34O6qBy203mt_4NvVbegIcS49IzyGtfn_a4OLbEGnz-gOnS2ee0Js6g=="
  },
  {
    "scheme": "RSA_2048_PKCS1_SIGN",
    "key": "eyJmb28iOiJiYXIiLCJiYXoiOiJxdXoiLCJyYW5kIjpbNTUsNTMsNDgsMTAyLDEwMSw1MywxMDIsMTAwLDEwMSw1Niw5OCw1NCw1Myw1MCw5NywxMDAsNTcsOTksNDksMTAwLDU2LDk4LDEwMiw1MSwxMDEsNDksNDksMTAwLDEwMSw1NSw5Nyw1Nl19.iLn4QFok4vvDRYwptUdakWPpwCxxAGljka9p2x4EMqV0gZqTI-VjL9J9w2m_FKFrSauVfcbl_cAKBfo12JL8a7FPIA0HEOqZX-bOGu2Z5zETeaz-4i9EY9NDO6eoKFfTKQHxHQt13nWuhj8LdLZN-9NW9AJTWyGPo4UwE5-bprRP90jCDjpRY6wu0-69MyVCSG-3GMOIpItfhYteXGM8veneijlYeMgRViK4IIdW28m6WhFWE1NN0DiBETCeC4O4mF3eGhN2gs60v3WK2Yte42i3UWyivxeseF5ObbVnrePrSM-kBPBuqBYzXSNYZgNGQ85WOJDKRHgdeW0Q2frumw=="
  },
  {
    "scheme": "RSA_2048_PKCS1_ENCRYPT",
    "key": "lpRbtMIVWvsplLXlwfw41L3hfM1_Xflr1XKLwoncPEi__v7Wpt6I3KhIu3VDcW6vf5kzK3rWHUGefcyglkySG4hRVLUqaf2w3mkagn9RJBROLdfrVr-tG4AyaNjILhCF99gYvHuky32CMRn8c4sexcXSu1Tp1meRbN4AyYvGntq8lfwy-NDeCFdOTV-Q54idKCKTjS1sadP9K-t7zSUA3_CfqRFI7e5jBAOwl-okPWU_LGOWpG16xZI7tJCSd6zBtnCaEI0Bq1noLiSMFHEb1QdjxeuxlzQIrxfP0qTmrUEQHe6QHCj8UH9_NF2qDVbW9uY5LMCyjLOAIvE_XpgqSQ=="
  },
  {
    "scheme": "RSA_2048_JWT_RS256",
    "key": "eyJhbGciOiJSUzI1NiJ9.eyJmb28iOiJiYXIiLCJiYXoiOiJxdXoiLCJyYW5kIjpbNTcsNTIsNTEsNTIsNTcsMTAxLDk3LDU0LDk5LDUxLDU2LDUyLDUwLDk4LDQ5LDU2LDQ4LDk3LDEwMCw5Nyw1NCw1Miw0OSw1NSw5OCw1MSw5Nyw1MCwxMDIsNTEsMTAxLDQ4XX0.dkRL-KqOGrFkAL9PRL38XSVFpSvpUSiEoAb_loAMvkqT_dD6girVaCNC3z5BLMaiJCc1OKNZXcvPItbMxxbnXewWZsGBeZeRtFLLsRIH49URdA3N4XOr2old22rT5iZeMLPQwND_XuThpinIROxf4JZ1z1t0-IqnnewQl9E4W7z2HiIeCMyCiqHROxx6zrBZJkrrDCcifb6jYUxeHemqC3V6odMCP_vBJGTFOA8xuDdaghHOtmFD1j35l87UauBko0IqgPLooQdsYqJCHFwW9RPf4YxS5wwLiBlpAmhMKIw7uh1KHdXN20JVsObJkwiJWlgiwIQCZJGNrVKxJyH9cQ"
  }
]

[ezekg]

Consider renaming encryptionScheme to something like crypto, scheme, or cryptoScheme? Encryption scheme isn’t entirely “correct”, since signing and JWTs aren’t encryption.

[ezekg]

Also, should we generate private keys per-product and use that for this instead of the account’s private key? Right now, an offline verified license would be valid across multiple products unless explicitly checked (i.e. the license payload includes a product prop or similar).

This is alright, since other license keys are also "valid" unless an explicit product scope is given. The product ID can be embedded within the key manually, if that's needed.