public static byte[] GetAdditionalData(FileStream inputFile, byte[] ephemeralPublicKey)
{
byte[] ciphertextLength = BitConversion.GetBytes(inputFile.Length - Constants.FileHeadersLength);
byte[] magicBytes = FileHeaders.ReadMagicBytes(inputFile);
byte[] formatVersion = FileHeaders.ReadFileFormatVersion(inputFile);
FileHeaders.ValidateFormatVersion(formatVersion, Constants.EncryptionVersion);
return(Arrays.Concat(ciphertextLength, magicBytes, formatVersion, ephemeralPublicKey));
}
public static byte[] GetAdditionalData(string inputFilePath)
{
byte[] magicBytes = FileHeaders.ReadMagicBytes(inputFilePath);
byte[] formatVersion = FileHeaders.ReadFileFormatVersion(inputFilePath);
FileHeaders.ValidateFormatVersion(inputFilePath, formatVersion, Constants.EncryptionVersion);
long fileLength = FileHandling.GetFileLength(inputFilePath);
int headersLength = FileHeaders.GetHeadersLength();
byte[] ciphertextLength = BitConverter.GetBytes(fileLength - headersLength);
return(Utilities.ConcatArrays(magicBytes, formatVersion, ciphertextLength));
}
public static bool VerifySignature(string signatureFilePath, string filePath, byte[] publicKey, out string comment)
{
using var signatureFile = new FileStream(signatureFilePath, FileMode.Open, FileAccess.Read, FileShare.Read, Constants.FileStreamBufferSize, FileOptions.SequentialScan);
byte[] magicBytes = GetMagicBytes(signatureFile);
byte[] formatVersion = GetFormatVersion(signatureFile);
FileHeaders.ValidateFormatVersion(formatVersion, Constants.SignatureVersion);
byte[] preHashed = GetPreHashedHeader(signatureFile);
byte[] fileSignature = GetFileSignature(signatureFile);
byte[] commentBytes = GetCommentBytes(signatureFile);
byte[] signatureFileBytes = Arrays.Concat(magicBytes, formatVersion, preHashed, fileSignature, commentBytes);
bool validGlobalSignature = VerifyGlobalSignature(signatureFile, signatureFileBytes, publicKey);
if (!validGlobalSignature)
{
comment = string.Empty;
return(false);
}
bool preHash = BitConverter.ToBoolean(preHashed);
byte[] fileBytes = GetFileBytes(filePath, preHash);
comment = Encoding.UTF8.GetString(commentBytes);
return(PublicKeyAuth.VerifyDetached(fileSignature, fileBytes, publicKey));
}
public static bool VerifySignature(string signatureFilePath, string filePath, byte[] publicKey)
{
using var signatureFile = new FileStream(signatureFilePath, FileMode.Open, FileAccess.Read, FileShare.Read, Constants.FileStreamBufferSize, FileOptions.RandomAccess);
// Verify the global signature
byte[] magicBytes = GetMagicBytes(signatureFile);
byte[] formatVersion = GetFormatVersion(signatureFile);
FileHeaders.ValidateFormatVersion(signatureFilePath, formatVersion, Constants.SignatureVersion);
byte[] preHashedHeader = GetPreHashedHeader(signatureFile);
byte[] fileSignature = GetFileSignature(signatureFile);
_commentBytes = GetCommentBytes(signatureFile);
byte[] signatureFileBytes = Utilities.ConcatArrays(magicBytes, formatVersion, preHashedHeader, fileSignature, _commentBytes);
bool validGlobalSignature = VerifyGlobalSignature(signatureFile, signatureFileBytes, publicKey);
if (!validGlobalSignature)
{
return(false);
}
// Verify the file signature
bool preHashed = BitConverter.ToBoolean(preHashedHeader);
byte[] fileBytes = GetFileBytes(filePath, preHashed);
return(PublicKeyAuth.VerifyDetached(fileSignature, fileBytes, publicKey));
}