private static byte[] DecryptBytes(byte[][] parts, object key, JweAlgorithm?jweAlg, JweEncryption?jweEnc, JwtSettings settings = null)
{
byte[] header = parts[0];
byte[] encryptedCek = parts[1];
byte[] iv = parts[2];
byte[] cipherText = parts[3];
byte[] authTag = parts[4];
JwtSettings jwtSettings = GetSettings(settings);
IDictionary <string, object> jwtHeader = jwtSettings.JsonMapper.Parse <Dictionary <string, object> >(Encoding.UTF8.GetString(header));
JweAlgorithm headerAlg = jwtSettings.JwaAlgorithmFromHeader((string)jwtHeader["alg"]);
JweEncryption headerEnc = jwtSettings.JweAlgorithmFromHeader((string)jwtHeader["enc"]);
IKeyManagement keys = jwtSettings.Jwa(headerAlg);
IJweAlgorithm enc = jwtSettings.Jwe(headerEnc);
if (keys == null)
{
throw new JoseException(string.Format("Unsupported JWA algorithm requested: {0}", headerAlg));
}
if (enc == null)
{
throw new JoseException(string.Format("Unsupported JWE algorithm requested: {0}", headerEnc));
}
if (jweAlg != null && (JweAlgorithm)jweAlg != headerAlg)
{
throw new InvalidAlgorithmException("The algorithm type passed to the Decrypt method did not match the algorithm type in the header.");
}
if (jweEnc != null && (JweEncryption)jweEnc != headerEnc)
{
throw new InvalidAlgorithmException("The encryption type passed to the Decrypt method did not match the encryption type in the header.");
}
byte[] cek = keys.Unwrap(encryptedCek, key, enc.KeySize, jwtHeader);
byte[] aad = Encoding.UTF8.GetBytes(Compact.Serialize(header));
byte[] plainText = enc.Decrypt(aad, cek, iv, cipherText, authTag);
if (jwtHeader.ContainsKey("zip"))
{
var alg = (string)jwtHeader["zip"];
var compression = jwtSettings.Compression(GetJweCompression(alg));
if (compression == null)
{
throw new JoseException(string.Format("Unsupported compressions algorithm requested: {0}", alg));
}
plainText = compression.Decompress(plainText);
}
return(plainText);
}
/// <summary>
/// Encodes given binary data to JWT token and applies requested encryption/compression algorithms.
/// </summary>
/// <param name="payload">Binary data to encode (not null)</param>
/// <param name="key">key for encryption, suitable for provided JWS algorithm, can be null.</param>
/// <param name="alg">JWT algorithm to be used.</param>
/// <param name="enc">encryption algorithm to be used.</param>
/// <param name="compression">optional compression type to use.</param>
/// <param name="extraHeaders">optional extra headers to pass along with the payload.</param>
/// <param name="settings">optional settings to override global DefaultSettings</param>
/// <returns>JWT in compact serialization form, encrypted and/or compressed.</returns>
public static string EncodeBytes(byte[] payload, object key, JweAlgorithm alg, JweEncryption enc, JweCompression?compression = null, IDictionary <string, object> extraHeaders = null, JwtSettings settings = null)
{
if (payload == null)
{
// https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/nameof
// nameof is not defined prior to c# 6.0 spec
// throw new ArgumentNullException(nameof(payload));
throw new ArgumentNullException("payload is null");
}
JwtSettings jwtSettings = GetSettings(settings);
IKeyManagement keys = jwtSettings.Jwa(alg);
IJweAlgorithm _enc = jwtSettings.Jwe(enc);
if (keys == null)
{
throw new JoseException(string.Format("Unsupported JWA algorithm requested: {0}", alg));
}
if (_enc == null)
{
throw new JoseException(string.Format("Unsupported JWE algorithm requested: {0}", enc));
}
IDictionary <string, object> jwtHeader = new Dictionary <string, object> {
{ "alg", jwtSettings.JwaHeaderValue(alg) }, { "enc", jwtSettings.JweHeaderValue(enc) }
};
Dictionaries.Append(jwtHeader, extraHeaders);
byte[][] contentKeys = keys.WrapNewKey(_enc.KeySize, key, jwtHeader);
byte[] cek = contentKeys[0];
byte[] encryptedCek = contentKeys[1];
if (compression.HasValue)
{
jwtHeader["zip"] = jwtSettings.CompressionHeader(compression.Value);
payload = jwtSettings.Compression(compression.Value).Compress(payload);
}
byte[] header = Encoding.UTF8.GetBytes(jwtSettings.JsonMapper.Serialize(jwtHeader));
byte[] aad = Encoding.UTF8.GetBytes(Compact.Serialize(header));
byte[][] encParts = _enc.Encrypt(aad, payload, cek);
return(Compact.Serialize(header, encryptedCek, encParts[0], encParts[1], encParts[2]));
}
/// <summary>
/// Encodes given binary data to JWT token and applies requested encryption/compression algorithms.
/// </summary>
/// <param name="payload">Binary data to encode (not null)</param>
/// <param name="key">key for encryption, suitable for provided JWS algorithm, can be null.</param>
/// <param name="settings">optional settings to override global DefaultSettings</param>
/// <returns>JWT in compact serialization form, encrypted and/or compressed.</returns>
public static string EncodeBytes(byte[] payload, object key, JweAlgorithm alg, JweEncryption enc, JweCompression?compression = null, IDictionary <string, object> extraHeaders = null, JwtSettings settings = null)
{
if (payload == null)
{
throw new ArgumentNullException(nameof(payload));
}
JwtSettings jwtSettings = GetSettings(settings);
IKeyManagement keys = jwtSettings.Jwa(alg);
IJweAlgorithm _enc = jwtSettings.Jwe(enc);
if (keys == null)
{
throw new JoseException(string.Format("Unsupported JWA algorithm requested: {0}", alg));
}
if (_enc == null)
{
throw new JoseException(string.Format("Unsupported JWE algorithm requested: {0}", enc));
}
IDictionary <string, object> jwtHeader = new Dictionary <string, object> {
{ "alg", jwtSettings.JwaHeaderValue(alg) }, { "enc", jwtSettings.JweHeaderValue(enc) }
};
Dictionaries.Append(jwtHeader, extraHeaders);
byte[][] contentKeys = keys.WrapNewKey(_enc.KeySize, key, jwtHeader);
byte[] cek = contentKeys[0];
byte[] encryptedCek = contentKeys[1];
if (compression.HasValue)
{
jwtHeader["zip"] = JweCompressionMethods[compression.Value];
payload = jwtSettings.Compression(compression.Value).Compress(payload);
}
byte[] header = Encoding.UTF8.GetBytes(jwtSettings.JsonMapper.Serialize(jwtHeader));
byte[] aad = Encoding.UTF8.GetBytes(Compact.Serialize(header));
byte[][] encParts = _enc.Encrypt(aad, payload, cek);
return(Compact.Serialize(header, encryptedCek, encParts[0], encParts[1], encParts[2]));
}
/// <summary>
/// Encrypts given binary plaintext using JWE and applies requested encryption/compression algorithms.
/// </summary>
/// <param name="plaintext">Binary data to encrypt (not null)</param>
/// <param name="recipients">The details of who to encrypt the plaintext (or rather the CEK) to.</param>
/// <param name="enc">encryption algorithm to be used to encrypt the plaintext.</param>
/// <param name="aad">additional authentication data (SerializationMode.Json only)</param>
/// <param name="mode">serialization mode to use. Note only one recipient can be specified for compact and flattened json serialization.</param>
/// <param name="compression">optional compression type to use.</param>
/// <param name="extraProtectedHeaders">optional extra headers to put in the protected header.</param>
/// <param name="unprotectedHeaders">optional unprotected headers</param>
/// <param name="settings">optional settings to override global DefaultSettings</param>
/// <returns>JWT in compact serialization form, encrypted and/or compressed.</returns>
public static string EncryptBytes(byte[] plaintext, IEnumerable <JweRecipient> recipients, JweEncryption enc, byte[] aad = null, SerializationMode mode = SerializationMode.Json, JweCompression?compression = null, IDictionary <string, object> extraProtectedHeaders = null, IDictionary <string, object> unprotectedHeaders = null, JwtSettings settings = null)
{
if (plaintext == null)
{
throw new ArgumentNullException(nameof(plaintext));
}
settings = GetSettings(settings);
IJweAlgorithm _enc = settings.Jwe(enc);
if (_enc == null)
{
throw new JoseException(string.Format("Unsupported JWE enc requested: {0}", enc));
}
IDictionary <string, object> joseProtectedHeader = Dictionaries.MergeHeaders(
new Dictionary <string, object> {
{ "enc", settings.JweHeaderValue(enc) }
},
extraProtectedHeaders);
byte[] cek = null;
var recipientsOut = new List <JweRecipient>();
foreach (var recipient in recipients)
{
IKeyManagement keys = settings.Jwa(recipient.Alg);
if (keys == null)
{
throw new JoseException(string.Format("Unsupported JWE alg requested: {0}", recipient.Alg));
}
// joseHeader - is merge of headers
// - key management will read from (e.g. enc,apv,apu - ECDH-ES)
// - key management will write to (e.g. iv, tag - AesGcmKW)
IDictionary <string, object> joseHeader = Dictionaries.MergeHeaders(
joseProtectedHeader,
new Dictionary <string, object> {
{ "alg", settings.JwaHeaderValue(recipient.Alg) }
},
recipient.Header,
unprotectedHeaders
);
byte[] encryptedCek;
if (cek == null)
{
byte[][] contentKeys = keys.WrapNewKey(_enc.KeySize, recipient.Key, joseHeader);
cek = contentKeys[0];
encryptedCek = contentKeys[1];
}
else
{
encryptedCek = keys.WrapKey(cek, recipient.Key, joseHeader);
}
// For the per-receipient header we want the headers from the result of IKeyManagements key wrapping but without the
// shared headers
IDictionary <string, object> recipientHeader = joseHeader
.Where(
kvp => !joseProtectedHeader.ContainsKey(kvp.Key) &&
(unprotectedHeaders == null || !unprotectedHeaders.ContainsKey(kvp.Key))
)
.ToDictionary(kvp => kvp.Key, kvp => kvp.Value);
recipientsOut.Add(new JweRecipient(encryptedCek, recipientHeader));
}
if (compression.HasValue)
{
joseProtectedHeader["zip"] = settings.CompressionHeader(compression.Value);
plaintext = settings.Compression(compression.Value).Compress(plaintext);
}
switch (mode)
{
case SerializationMode.Compact:
{
if (recipientsOut.Count != 1)
{
throw new JoseException("Only one recipient is supported by the JWE Compact Serialization.");
}
if (aad != null)
{
throw new JoseException("JWE AAD value is not valid for JWE Compact Serialization.");
}
joseProtectedHeader = Dictionaries.MergeHeaders(recipientsOut[0].Header, joseProtectedHeader);
byte[] header = Encoding.UTF8.GetBytes(settings.JsonMapper.Serialize(joseProtectedHeader));
aad = Encoding.UTF8.GetBytes(Compact.Serialize(header));
byte[][] encParts = _enc.Encrypt(aad, plaintext, cek);
return(new JweToken(
header,
null,
recipientsOut,
null,
encParts[0],
encParts[1],
encParts[2],
mode)
.AsString());
}
case SerializationMode.Json:
{
var protectedHeaderBytes = Encoding.UTF8.GetBytes(settings.JsonMapper.Serialize(joseProtectedHeader));
byte[] asciiEncodedProtectedHeader = Encoding.ASCII.GetBytes(Base64Url.Encode(protectedHeaderBytes));
byte[][] encParts = _enc.Encrypt(Aad(protectedHeaderBytes, aad), plaintext, cek);
return(new JweToken(
protectedHeaderBytes,
unprotectedHeaders,
recipientsOut,
aad,
encParts[0],
encParts[1],
encParts[2],
mode)
.AsString(settings.JsonMapper));
}
default:
throw new JoseException($"Unsupported serializtion mode: {mode}.");
}
}
/// <summary>
/// Decypts a JWE by performing necessary decompression/decryption and authenticated decryption as defined in RFC7516.
/// </summary>
/// <param name="jwe">JWE to decrypt.</param>
/// <param name="key">key for decoding suitable for JWE algorithm used to encrypt the CEK.</param>
/// <param name="expectedJweAlg">The algorithm type that we expect to receive in the header.</param>
/// <param name="expectedJweEnc">The encryption type that we expect to receive in the header.</param>
/// <param name="settings">optional settings to override global DefaultSettings</param>
/// <returns>Decrypted JweToken object</returns>
/// <exception cref="IntegrityException">if AEAD operation validation failed</exception>
/// <exception cref="EncryptionException">if JWE can't be decrypted</exception>
/// <exception cref="InvalidAlgorithmException">if encryption or compression algorithm is not supported</exception>
public static JweToken Decrypt(string jwe, object key, JweAlgorithm?expectedJweAlg = null, JweEncryption?expectedJweEnc = null, JwtSettings settings = null)
{
Ensure.IsNotEmpty(jwe, "Incoming jwe expected to be in a valid serialization form, not empty, whitespace or null.");
settings = GetSettings(settings);
JweToken token = Headers(jwe);
if (token.ProtectedHeaderBytes == null && token.Encoding == SerializationMode.Compact)
{
throw new JoseException(string.Format("Protected header was missing but required with compact encoding."));
}
var exceptions = new List <Exception>();
foreach (var recipient in token.Recipients)
{
var headerAlg = settings.JwaAlgorithmFromHeader((string)recipient.JoseHeader["alg"]);
var encryptedCek = recipient.EncryptedCek;
// skip recipient if asked to do strict validation
if (expectedJweAlg != null && expectedJweAlg != headerAlg)
{
continue;
}
IKeyManagement keys = settings.Jwa(headerAlg);
if (keys == null)
{
throw new JoseException(string.Format("Unsupported JWA algorithm requested: {0}", headerAlg));
}
try
{
JweEncryption headerEnc = settings.JweAlgorithmFromHeader((string)recipient.JoseHeader["enc"]);
IJweAlgorithm enc = settings.Jwe(headerEnc);
if (enc == null)
{
throw new JoseException(string.Format("Unsupported JWE algorithm requested: {0}", headerEnc));
}
if (expectedJweEnc != null && expectedJweEnc != headerEnc)
{
throw new InvalidAlgorithmException("The encryption type passed to the Decrypt method did not match the encryption type in the header.");
}
byte[] cek = keys.Unwrap(recipient.EncryptedCek, key, enc.KeySize, recipient.JoseHeader);
byte[] plaintext = enc.Decrypt(Aad(token.ProtectedHeaderBytes, token.Aad), cek, token.Iv, token.Ciphertext, token.AuthTag);
if (recipient.JoseHeader.TryGetValue("zip", out var compressionAlg))
{
var compression = settings.Compression((string)compressionAlg);
plaintext = compression.Decompress(plaintext);
}
token.PlaintextBytes = plaintext;
token.Recipient = recipient;
return(token);
}
catch (ArgumentException ex)
{
exceptions.Add(ex);
}
catch (JoseException ex)
{
exceptions.Add(ex);
}
}
// nobody was eligable for decryption
if (exceptions.Count == 0)
{
throw new InvalidAlgorithmException("The algorithm type passed to the Decrypt method did not match the algorithm type in the header.");
}
// decryption failed
if (exceptions.Select(e => new KeyValuePair <Type, String>(e.GetType(), e.Message)).Distinct().Count() == 1)
{
// throw the first
throw exceptions[0];
}
else
{
throw new JoseException($"No recipients able to decrypt.", new AggregateException(exceptions));
}
}
