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Wikipedia / Integrated Encryption Scheme

The Integrated Encryption Scheme (IES) is a hybrid encryption scheme which provides semantic security against an adversary who is able to use chosen-plaintext or chosen-ciphertext attacks. The security of the scheme is based on the computational Diffie–Hellman problem. Two variants of IES are specified: Discrete Logarithm Integrated Encryption Scheme (DLIES) and Elliptic Curve Integrated Encryption Scheme (ECIES), which is also known as the Elliptic Curve Augmented Encryption Scheme or simply the Elliptic Curve Encryption Scheme. These two variants are identical up to the change of an underlying group.

Informal description of DLIES

As a brief and informal description and overview of how IES works, a Discrete Logarithm Integrated Encryption Scheme (DLIES) is used, focusing on illuminating the reader's understanding, rather than precise technical details.

  1. Alice learns Bob's through a public key infrastructure or some other distribution method..

  2. .

  3. using this information and a key derivation function

  4. (using an authenticated encryption scheme

  5. .

  6. .

Note that the scheme does not provide Bob with any assurance as to who really sent the message: This scheme does nothing to stop anyone from pretending to be Alice.

Formal description of ECIES

Required information

To send an encrypted message to Bob using ECIES, Alice needs the following information:

Encryption

Alice does the following:

  1. )

  2. uses a KDF to derive symmetric encryption keys and MAC

Decryption

Bob does the following:

  1. ), or outputs failed

  2. uses MAC to check the tag and outputs failed

References