base64 support

[SaadArdati]

Hello, I'm trying to implement server-side reward-ad verification through dart.
Google's Admob has very clear documentation on how to implement this in java
https://developers.google.com/admob/android/rewarded-video-ssv#fetch_public_keys
And a github sample:

• public key parsing: https://github.com/google/tink/blob/44cbb529d491ffd7e8756be5fa6abb06cb952ec5/apps/rewardedads/java/src/main/java/com/google/crypto/tink/apps/rewardedads/RewardedAdsVerifier.java#L299
• verification: https://github.com/google/tink/blob/44cbb529d491ffd7e8756be5fa6abb06cb952ec5/apps/rewardedads/java/src/main/java/com/google/crypto/tink/apps/rewardedads/RewardedAdsVerifier.java#L147-L162

The public keys are retrieved from the url: https://www.gstatic.com/admob/reward/verifier-keys.json

The keys are in base64 and the documentation also works with it as base64.

When trying to implement it with eosdart, I'm met with the error
Invalid argument(s): Non-base58 character when creating the publicKey var

Here's my code:

      // var base64 = base64Url.decode(admobPublicKeys[keyId]);
      var publicKey = EOSPrivateKey.fromString(admobPublicKeys[keyId]).toEOSPublicKey();

      var privateKey = EOSPrivateKey.fromString(signature);
      var signer = privateKey.signString(data);

      return signer.verify(data, publicKey);

I'm not too familiar with ECC verification. So if I made any other mistakes, please tell me.
However, for the current issue at hand, the keys are in base64, while the package requires base58. I'm not sure what to do.

[redDwarf03]

hello.
any solutions ?

[fzxu]

@redDwarf03 May I know why it is related to Google Admob? this project is for EOS crypto network.