AWS Cognito user authentication Missing required parameter SRP_A
<p>I am trying to use AWS Cognito services for user authentication through <em>ruby</em> SDK.</p>

<p>I could able to sign_up, confirm sign_up process using the methods</p>

<pre><code>  resp = client.sign_up({ client_id: "ClientIdType",
                          secret_hash: "SecretHashType",
                          username: "UsernameType",
                          password: "PasswordType",
                          user_attributes: [{ name:"AttributeNameType", 
                                    value: "AttributeValueType",
                                     }],
                          validation_data: [{
                          name: "AttributeNameType",
                          value: "AttributeValueType",
                                  }]
                          })
</code></pre>

<p>and confirm_sign_up using </p>

<pre><code>  resp = client.confirm_sign_up({client_id: "ClientIdType",
                                 secret_hash: "SecretHashType",
                                 username: "UsernameType",
                                 confirmation_code: "ConfirmationCodeType"
                                })
</code></pre>

<p>But while trying to sign in the user through initiate_auth I am getting an error <strong>Missing required parameter SRP_A</strong></p>

<pre><code>cog_provider.initiate_auth({client_id: "xxxxxxxxx", auth_parameters: { username: "xxx", password: "xxx"}, auth_flow: "USER_SRP_AUTH"})
</code></pre>

<p>What does SRP_A indicate where to find it.</p>

<p>I have searched for this problem and It is suggested to use the <code>admin_initiate_auth</code> method for signing in a user which I don't believe a best practice.</p>