Skip to content

Instantly share code, notes, and snippets.

@dzmitry-savitski

dzmitry-savitski/decrypt.js

Created April 9, 2025 14:13
Show Gist options

  • Select an option

    Learn more about clone URLs
  • Save dzmitry-savitski/caeef097b285609687d901db21768f36 to your computer and use it in GitHub Desktop.

Select an option

Learn more about clone URLs
Save dzmitry-savitski/caeef097b285609687d901db21768f36 to your computer and use it in GitHub Desktop.
Download ZIP

Revisions

  1. dzmitry-savitski created this gist Apr 9, 2025.
    19 changes: 19 additions & 0 deletions decrypt.js
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,19 @@
    import { jwtDecrypt } from 'jose';

    // Your base64-encoded 256-bit key (should decode to 32 bytes)
    const base64Key = 'yourBase64EncodedKeyHere'; // example: "3q2+7w==..."

    // Decode base64 to a Uint8Array
    const key = Uint8Array.from(Buffer.from(base64Key, 'base64'));

    // Your JWE compact token
    const token = 'eyJalgIjoiZGlyIiwiZW5jIjoiQTI1NkdDTSJ9..<IV>.<ciphertext>.<tag>';

    async function decrypt() {
    const { payload, protectedHeader } = await jwtDecrypt(token, key);

    console.log('🔓 Decrypted payload:', new TextDecoder().decode(payload));
    console.log('📄 Header:', protectedHeader);
    }

    decrypt().catch(err => console.error('Decryption failed:', err));