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Add: SealWithRandomNonce logic #92

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Merged
qmuntal merged 2 commits into from
May 27, 2025
Merged

Add: SealWithRandomNonce logic #92

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96a8030
add:sealrandomwithnonce logic
mertakman May 22, 2025
3edf1de
fix:address pr comments
mertakman May 26, 2025
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34 changes: 34 additions & 0 deletions cng/aes.go
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Original file line number Diff line number Diff line change
Expand Up @@ -337,6 +337,40 @@ func (g *aesGCM) Seal(dst, nonce, plaintext, additionalData []byte) []byte {
return ret
}

func (g *aesGCM) SealWithRandomNonce(out, nonce, plaintext, additionalData []byte) {
if uint64(len(plaintext)) > uint64((1<<32)-2)*aesBlockSize {
panic("crypto/cipher: message too large for GCM")
}
if len(nonce) != gcmStandardNonceSize {
panic("crypto/cipher: incorrect nonce length given to GCMWithRandomNonce")
}
if len(out) != len(plaintext)+gcmTagSize {
panic("crypto/cipher: incorrect output length given to GCMWithRandomNonce")
}
if subtle.InexactOverlap(out, plaintext) {
panic("crypto/cipher: invalid buffer overlap of output and input")
}
if subtle.AnyOverlap(out, additionalData) {
panic("crypto/cipher: invalid buffer overlap of output and additional data")
}

if g.tls != cipherGCMTLSNone {
panic("cipher: TLS 1.2 and 1.3 modes do not support random nonce")
}

RandReader.Read(nonce)
info := bcrypt.NewAUTHENTICATED_CIPHER_MODE_INFO(nonce, additionalData, out[len(out)-gcmTagSize:])
var encSize uint32
err := bcrypt.Encrypt(g.kh, plaintext, unsafe.Pointer(info), nil, out, &encSize, 0)
if err != nil {
panic(err)
}
if int(encSize) != len(plaintext) {
panic("crypto/cipher: plaintext not fully encrypted")
}
runtime.KeepAlive(g)
}

var errOpen = errors.New("cipher: message authentication failed")

func (g *aesGCM) Open(dst, nonce, ciphertext, additionalData []byte) ([]byte, error) {
Expand Down