Module concordium_base::elgamal

Implementation of elgamal public key encryption and decryption over a Curve.

Structs

• BabyStepGiantStep
  The table for the baby step giant step algorithm, with some auxiliary data.
• Cipher
  Encrypted message.
• Message
  Message to be encrypted. This is a simple wrapper around a group element, but we use it for added type safety.
• PublicKey
  Elgamal public key .
• Randomness
  Randomness which was used to encrypt a message.
• SecretKey
  Elgamal secret key packed together with a chosen generator.

Enums

• ChunkSize
  Possible chunk sizes in bits.

Functions

• chunks_to_value
  NB: This function does not ensure there is no overflow. It assumes that the chunks are reasonable and at most 64 bits.
• decrypt_from_chunks
  Wrapper around decrypt_from_chunks_given_generator that uses the generator that is part of the key.
• decrypt_from_chunks_given_generator
• decrypt_from_chunks_given_table
• encrypt_in_chunks
  Wrapper around encrypt_in_chunks_given_generator that uses the generator that is part of the public key.
• encrypt_in_chunks_given_generator
• encrypt_u64_in_chunks_given_generator
  Encrypt a single u64 value in chunks in the exponent of the given generator.
• multicombine
  Perform a “linear combination in the exponent”, i.e., multiply each of the ciphers with the corresponding scalar, and sum them together. If cipher C_i ciphers is an encryption in the exponent of the value v_i, then the resulting cipher is a valid encryption in the exponent of the value \sum_i v_i \cdot s_i where s_i is the i-th scalar.
• value_to_chunks
  Transform a scalar into as many chunks as necessary. The chunks are returned in little-endian order.

Type Aliases

• BabyStepGiantStepTable