Android cryptography library - EasyCrypt

Additional

Language
Kotlin
Version
1.3.4 (Mar 25, 2018)
Created
Jun 30, 2017
Updated
Mar 25, 2018
Owner
Priyank Vasa (ryan652)
Contributor
Priyank Vasa (ryan652)
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Source code

Blurb

EasyCrypt

Secure and efficient cryptography library for Android. (Auto fix SecureRandom bugs in API 18 and below.)

Note: EasyCrypt uses only secure implementations and all the known Crypto bugs are already dealt with properly. More information here.

Features

  • AES-256 encryption algorithm
  • CBC/CTR mode of operations
  • Block padding with PKCS7 (only with CBC)
  • Computationally secure random salt (of cipher block size)
  • Password stretching with PBKDF2
  • Random IV generated on each encryption (16 bytes)
  • Supports MD5, SHA1, and SHA2 hash functions
  • Generate secure keys with SecureRandom or random.org
  • Asymmetric encryption with RSA
  • Auto handle large data by using hybrid asymmetric encryption
  • Asymmetric RSA signing and verification
  • Supported RSA key sizes are 2048 bits and 4096 bits
  • Password analysis for strength, crack times, weakness, etc using nulab's zxcvbn4j library

Sample app

Download the sample app from play store.

Install

Add in your app's build.gradle

dependencies {
    ..
    implementation "com.pvryan.easycrypt:easycrypt:1.3.3"
}

Usage

val eCryptSymmetric = ECSymmetric()
val eCryptAsymmetric = ECAsymmetric()
val eCryptHash = ECHash()
val eCryptPass = ECPasswords()

Symmetric key encryption

Encrypt data

eCryptSymmetric.encrypt (input, password,
    object : ECResultListener {

        // Optional
        override fun onProgress(newBytes: Int, bytesProcessed: Long, totalBytes: Long) {

        }

        override fun <T> onSuccess(result: T) {

        }

        override fun onFailure(message: String, e: Exception) {

        }
    },
    outputFile // Optional
)

Decrypt data

eCryptSymmetric.decrypt(input, password,
        object : ECResultListener {

            // Optional
            override fun onProgress(newBytes: Int, bytesProcessed: Long, totalBytes: Long) {

            }

            override fun <T> onSuccess(result: T) {

            }

            override fun onFailure(message: String, e: Exception) {

            }
        },
        outputFile // Optional
)

Asymmetric key encryption

Encrypt data

eCryptAsymmetric.generateKeyPair(object : ECRSAKeyPairListener {

     override fun onSuccess(keyPair: KeyPair) {
         privateKey = keyPair.private as RSAPrivateKey // Save private key
         eCryptAsymmetric.encrypt(input, keyPair.public as RSAPublicKey,
                 object : ECResultListener {

                     // Optional
                     override fun onProgress(newBytes: Int, bytesProcessed: Long, totalBytes: Long) {

                     }

                     override fun <T> onSuccess(result: T) {

                     }

                     override fun onFailure(message: String, e: Exception) {

                     }
                 },
                 outputFile // Optional
         )
     }

     override fun onFailure(message: String, e: Exception) {
         e.printStackTrace()
     }

 }, keySize = eCryptAsymmetric.KeySizes._4096)

Decrypt data

eCryptAsymmetric.decrypt(input, privateKey,
        object : ECResultListener {

            // Optional
            override fun onProgress(newBytes: Int, bytesProcessed: Long, totalBytes: Long) {

            }

            override fun <T> onSuccess(result: T) {

            }

            override fun onFailure(message: String, e: Exception) {

            }
        },
        outputFile // Optional
)

Sign data

eCryptKeys.genRSAKeyPair(object : ECRSAKeyPairListener {

    override fun onGenerated(keyPair: KeyPair) {

        publicKey = keyPair.public as RSAPublicKey

        eCryptAsymmetric.sign(input,
                keyPair.private as RSAPrivateKey,
                object : ECResultListener {

                    // Optional
                    override fun onProgress(newBytes: Int, bytesProcessed: Long, totalBytes: Long) {

                    }

                    override fun <T> onSuccess(result: T) {

                    }

                    override fun onFailure(message: String, e: Exception) {

                    }
                },
                signatureOutputFile)
    }

    override fun onFailure(message: String, e: Exception) {

    }
})

Verify data

eCryptAsymmetric.verify(input, publicKey, signatureFile,
        object : ECVerifiedListener {
            override fun onSuccess(verified: Boolean) {

            }

            override fun onFailure(message: String, e: Exception) {

            }
        }
)

Hash data

eCryptHash.calculate(input, hashAlgorithm, // from ECHashAlgorithms
        object : ECResultListener {

            // Optional
            override fun onProgress(newBytes: Int, bytesProcessed: Long, totalBytes: Long) {

            }

            override fun <T> onSuccess(result: T) {

            }

            override fun onFailure(message: String, e: Exception) {

            }
        },
        outputFile // Optional
)

Analyze password

val analysis: ECPasswordAnalysis = ECPasswordAnalyzer.analyze("thisismypassword")

Input Output
File outputFile
FileInputStream outputFile
ByteArray String or outputFile (if provided)
ByteArrayInputStream String or outputFile (if provided)
String String or outputFile (if provided)
CharSequence String or outputFile (if provided)
Anything else InvalidParameterException

Generate key with SecureRandom (pseudo-random)

val password = eCryptPass.genSecureRandomPassword(length, charArrayOf(/*symbols to be used in password*/))

Generate key with Random.org (true random)

For sample to work enter your API key in FragmentPasswords

eCryptPass.genRandomOrgPassword(
        length,
        "random-org-api-key", //TODO: Replace with your random.org api key
        new ECPasswordListener() {

            @Override
            public void onFailure(@NonNull String message, @NonNull Exception e) {

            }

            @Override
            public void onSuccess(@NonNull String password) {

            }
        });

License

Copyright 2018 Priyank Vasa
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.