Message recovery is a feature of some digital signature schemes, whereas some or all of the message signed is embedded in the signature, recovered as part of signature verification, and thus needs not be transmitted.

A signature scheme with message recovery embeds at least a portion of the message (the recoverable part) in the signature. Signature verification will produce that part of the message, which thus needs not be transmitted. Some schemes allow partial message recovery, where another non-empty portion of the message (the non-recoverable part) is allowed and must be available to the verifier.

Signature schemes with message recovery have been codified by standards of the ISO/IEC 9796 family:

  • ISO/IEC 9796 was withdrawn in 2000; it is also known as ISO/IEC 9796-1, by the name of a draft.
  • ISO/IEC 9796-2 codifies three schemes based on integer factorization (RSA or Rabin); see this answer for details.
  • ISO/IEC 9796-3 codifies six schemes based on the discrete logarithm problem.