Online SHA1 hash generator

I have generated my SHA1 code from my keystore but when I try to create an OAuth client 2.0, Google game console is giving me the error: "Certificate fingerprint is invalid".

http://oi68.tinypic.com/23lgt2g.jpg

http://oi64.tinypic.com/iqy2rb.jpg

Anyone knows why this happens?How do I fix this?

I was trying to work with hashcash to generate hash with certain number of leading zeros for a random string. I cannot find much resource online. If any help is possible.

When you sign and distribute your Xamarin Android apps the wizard helps you create keystore for your app. However, wherever I looked on my mac I could not find the actual .keystore file anywhere. So how am I supposed to get the SHA-1 fingerprint for that keystore?

I've created a MongoDB user with the password "86f5ec4fd396195a99b6c2545180676bbb62b86327314399829b4ea00c53":

@mongo_client.command(  {    createUser: "my_user",    pwd:        "86f5ec4fd396195a99b6c2545180676bbb62b86327314399829b4ea00c53",    roles:      ["readWrite"]  })

When I check the SCRAM hashed password in MongoDB:

pp @mongo_client.command({usersInfo: 1, showCredentials: true}).documents.first["users"]

the output is:

[{"_id"=>"5cecd7773ab42f4cff2f08dd.myuser",  "user"=>"myuser",  "db"=>"5cecd7773ab42f4cff2f08dd",  "credentials"=>   {"SCRAM-SHA-1"=>     {"iterationCount"=>10000,      "salt"=>"PLoIONQY4paDiiCdwiyBMQ==",      "storedKey"=>"joVFIIyEgI9sE9nXXS4RXcBeLv4=",      "serverKey"=>"C3AZBq9hTuwMQtpJXdqZa3ZYKK8="},    "SCRAM-SHA-256"=>     {"iterationCount"=>15000,      "salt"=>"foJnBgfiaKjhAkg9KFSqKGuyb4uhbfvgPoqgpA==",      "storedKey"=>"8TsZfXwIz9XEKtFY0Ug0XjSn9QAwB7/6XpFc4AjW7Wc=",      "serverKey"=>"9R9Mj9u4cymqqHGdHBAm4xOjmkuDYQso+jECik4n+Gw="}},  "roles"=>[{"role"=>"readWrite", "db"=>"5cecd7773ab42f4cff2f08dd"}],  "mechanisms"=>["SCRAM-SHA-1", "SCRAM-SHA-256"]}]

How do I (using Ruby) convert my original cleartext password to the SCRAM-SHA-1/SCRAM-SHA-256 versions seen above?

The docs writes this about SCRAM:

In the implementation of SCRAM authentication mechanisms (e.g. SCRAM-SHA-1 and SCRAM-SHA-256), drivers MUST maintain a cache of computed SCRAM credentials. The cache entries SHOULD be identified by the password, salt, iteration count, and a value that uniquely identifies the authentication mechanism (e.g. "SHA1" or "SCRAM-SHA-256").

The cache entry value MUST be either the saltedPassword parameter or the combination of the clientKey and serverKey parameters.

What would actually happen if I had a hash collision while using git?

E.g. I manage to commit two files with the same sha1 checksum,would git notice it or corrupt one of the files?

Could git be improved to live with that, or would I have to change to a new hash algorithm?

(Please do not deflect this question by discussing how unlikely that is - Thanks)