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Addresses

Public-key-to-address

Calculate the address for a public key.

Signature
(public-key-to-address pub-key) → address
Arguments: pub-key — Guard (secp256k1-pub-key-p pub-key).
Returns: address — Type (byte-list20p address).

The address consists of the rightmost 160 bits of the 256-bit Keccak-256 hash of the serialized public key [YP:(284)]. This is equivalent to the rightmost 20 bytes of the 32-byte hash.

This function corresponds to ``part of'' the function A [YP:(284)], because it takes a public key as argument, corresponding to \mathtt{ECDSAPUBKEY}(p_\mathrm{r}) in [YP:(284)]. The function \mathtt{ECDSAPUBKEY} returns an array of 64 bytes [YP:(277)] which suggests that the public key is represented as an elliptic curve point in uncompressed form. Thus, we use the library function secp256k1-point-to-bytes to turn the public key into that form.

The function private-key-to-address calculates an address from a private key instead.

Definitions and Theorems

Function: public-key-to-address

(defun public-key-to-address (pub-key)
  (declare (xargs :guard (secp256k1-pub-key-p pub-key)))
  (let ((__function__ 'public-key-to-address))
    (declare (ignorable __function__))
    (b* ((pub-key (mbe :logic (secp256k1-pub-key-fix pub-key)
                       :exec pub-key))
         (uncompressed-form (secp256k1-point-to-bytes pub-key nil))
         (hash (keccak-256-bytes uncompressed-form))
         (address (nthcdr 12 hash)))
      address)))

Theorem: byte-list20p-of-public-key-to-address

(defthm byte-list20p-of-public-key-to-address
  (b* ((address (public-key-to-address pub-key)))
    (byte-list20p address))
  :rule-classes :rewrite)

Theorem: public-key-to-address-of-secp256k1-pub-key-fix-pub-key

(defthm public-key-to-address-of-secp256k1-pub-key-fix-pub-key
  (equal (public-key-to-address (secp256k1-pub-key-fix pub-key))
         (public-key-to-address pub-key)))

Theorem: public-key-to-address-secp256k1-pub-key-equiv-congruence-on-pub-key

(defthm
 public-key-to-address-secp256k1-pub-key-equiv-congruence-on-pub-key
 (implies (ecurve::secp256k1-pub-key-equiv pub-key pub-key-equiv)
          (equal (public-key-to-address pub-key)
                 (public-key-to-address pub-key-equiv)))
 :rule-classes :congruence)