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Function Repository Resource:

 Fernet

Source Notebook

Cryptographic utility function for encrypting and decrypting messages

Contributed by: Arnoud Buzing

ResourceFunction["Fernet"]["GenerateKey"]

generates a key for use with Fernet encryption and decryption.

ResourceFunction["Fernet"][{"Encrypt",key},message]

encrypts message using key.

ResourceFunction["Fernet"][{"Decrypt",key},data]

decrypts data using key.

Details

ResourceFunction["Fernet"] implements a simple, secure, symmetric (secret key) authenticated cryptographic method.
A generated ResourceFunction["Fernet"] key is a byte array that is URL-safe and "BASE64" encoded. This key must be kept safe.
ResourceFunction["Fernet"] encrypted data can be decrypted only with the orginal key.
The encryption key is in ByteArray format, but its equivalent string representation, from ByteArrayToString, is also supported.

Examples

Basic ExamplesFernet

Generate a cryptographic key for use with Fernet:

In[1]:=
key = ResourceFunction["Fernet"]["GenerateKey"]
Out[1]=

Encrypt a message using the cryptographic key:

In[2]:=
ba = ResourceFunction["Fernet"][{"Encrypt", key}, "This is a secret message! 😀"]
Out[2]=

The encrypted data has a "BASE64" compatible string format, so it can be used in URL requests:

In[3]:=
ba // ByteArrayToString
Out[3]=

Decrypt the message with the same key:

In[4]:=
ResourceFunction["Fernet"][{"Decrypt", key}, ba]
Out[4]=

Possible Issues (3) 

You can only decrypt data with the original Fernet key:

In[5]:=
key1 = ResourceFunction["Fernet"]["GenerateKey"]; ba = ResourceFunction["Fernet"][{"Encrypt", key1}, "Secret message"]; key2 = ResourceFunction["Fernet"]["GenerateKey"]; ResourceFunction["Fernet"][{"Decrypt", key2}, ba]
Out[4]=

You can not use arbitrary byte arrays as the encryption key:

In[6]:=
ResourceFunction[ "Fernet"][{"Encrypt", ByteArray[{1, 2, 3}]}, "Secret message"]
Out[6]=

Generated keys should be stored securely. One method of secure persistent storage is provided by SystemCredential:

In[7]:=
key = ResourceFunction["Fernet"]["GenerateKey"]; SystemCredential["my-secret-key"] = ByteArrayToString[key]; (* store the key as a base64 string *) SystemCredential["my-secret-key"]
Out[9]=

Encrypt using the key stored in SystemCredential:

In[10]:=
ba = ResourceFunction[ "Fernet"][{"Encrypt", SystemCredential["my-secret-key"]}, "Secret message"]
Out[10]=

Decrypt using the key stored in SystemCredential:

In[11]:=
ResourceFunction[ "Fernet"][{"Decrypt", SystemCredential["my-secret-key"]}, ba]
Out[11]=

Publisher

WolframExternalFunctions

Requirements

Wolfram Language 13.0 (December 2021) or above

Version History

  • 1.0.0 – 10 June 2024

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