mlkemtest.go

     1  // Copyright 2025 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Package mlkemtest provides testing functions for the ML-KEM algorithm.
     6  package mlkemtest
     7  
     8  import (
     9  	fips140mlkem "crypto/internal/fips140/mlkem"
    10  	"crypto/internal/fips140only"
    11  	"crypto/mlkem"
    12  	"errors"
    13  )
    14  
    15  // Encapsulate768 implements derandomized ML-KEM-768 encapsulation
    16  // (ML-KEM.Encaps_internal from FIPS 203) using the provided encapsulation key
    17  // ek and 32 bytes of randomness.
    18  //
    19  // It must only be used for known-answer tests.
    20  func Encapsulate768(ek *mlkem.EncapsulationKey768, random []byte) (sharedKey, ciphertext []byte, err error) {
    21  	if len(random) != 32 {
    22  		return nil, nil, errors.New("mlkemtest: Encapsulate768: random must be 32 bytes")
    23  	}
    24  	if fips140only.Enforced() {
    25  		return nil, nil, errors.New("crypto/mlkem/mlkemtest: use of derandomized encapsulation is not allowed in FIPS 140-only mode")
    26  	}
    27  	k, err := fips140mlkem.NewEncapsulationKey768(ek.Bytes())
    28  	if err != nil {
    29  		return nil, nil, errors.New("mlkemtest: Encapsulate768: failed to reconstruct key: " + err.Error())
    30  	}
    31  	sharedKey, ciphertext = k.EncapsulateInternal((*[32]byte)(random))
    32  	return sharedKey, ciphertext, nil
    33  }
    34  
    35  // Encapsulate1024 implements derandomized ML-KEM-1024 encapsulation
    36  // (ML-KEM.Encaps_internal from FIPS 203) using the provided encapsulation key
    37  // ek and 32 bytes of randomness.
    38  //
    39  // It must only be used for known-answer tests.
    40  func Encapsulate1024(ek *mlkem.EncapsulationKey1024, random []byte) (sharedKey, ciphertext []byte, err error) {
    41  	if len(random) != 32 {
    42  		return nil, nil, errors.New("mlkemtest: Encapsulate1024: random must be 32 bytes")
    43  	}
    44  	if fips140only.Enforced() {
    45  		return nil, nil, errors.New("crypto/mlkem/mlkemtest: use of derandomized encapsulation is not allowed in FIPS 140-only mode")
    46  	}
    47  	k, err := fips140mlkem.NewEncapsulationKey1024(ek.Bytes())
    48  	if err != nil {
    49  		return nil, nil, errors.New("mlkemtest: Encapsulate1024: failed to reconstruct key: " + err.Error())
    50  	}
    51  	sharedKey, ciphertext = k.EncapsulateInternal((*[32]byte)(random))
    52  	return sharedKey, ciphertext, nil
    53  }
    54
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