+/* Copyright (c) 1998,2011,2014 Apple Inc. All Rights Reserved.
+ *
+ * NOTICE: USE OF THE MATERIALS ACCOMPANYING THIS NOTICE IS SUBJECT
+ * TO THE TERMS OF THE SIGNED "FAST ELLIPTIC ENCRYPTION (FEE) REFERENCE
+ * SOURCE CODE EVALUATION AGREEMENT" BETWEEN APPLE, INC. AND THE
+ * ORIGINAL LICENSEE THAT OBTAINED THESE MATERIALS FROM APPLE,
+ * INC. ANY USE OF THESE MATERIALS NOT PERMITTED BY SUCH AGREEMENT WILL
+ * EXPOSE YOU TO LIABILITY.
+ ***************************************************************************
+ *
+ * NSCryptors.h - common cryptographic protocols
+ *
+ * Revision History
+ * ----------------
+ * ??? 1994 Blaine Garst at NeXT
+ * Created.
+ */
+
+
+#import <Foundation/NSObject.h>
+#import <Foundation/NSData.h>
+#import <Foundation/NSString.h>
+
+
+/************ Utilities ******************************************/
+
+#ifdef NeXT
+
+NSString *NSPromptForPassPhrase(NSString *prompt);
+ // useful for command line (/dev/tty) programs
+
+#endif NeXT
+
+/************ Data Hashing Protocol *****************/
+
+@protocol NSDataDigester
++ digester; // provides a concrete digester
+
+// primitives
+- (void)digestData:(NSData *)data; // use for multi-bite messages
+- (NSData *)messageDigest; // provide digest; re-init
+
+// conveniences that only use the above primitives
+// all in one gulp (eats salt first, if present)
+- (NSData *)digestData:(NSData *)data withSalt:(NSData *)salt;
+
+@end
+
+
+/****** Encryption/Decryption Protocol ***********/
+
+@protocol NSCryptor
+- (NSData *)encryptData:(NSData *)input;
+- (NSData *)decryptData:(NSData *)input;
+- (unsigned)keyBitsize;
+@end
+
+
+/*************** Public Key Services *************/
+
+@protocol NSPublicKey
+- (NSString *)publicKeyString;
+- (NSString *)algorithmName; // "Diffie-Hellman" "FEE" ...
+- (NSString *)usageName; // "Blaine Garst - home"
+- (NSData *)padWithPublicKey:(id <NSPublicKey>)otherKey;
+- (unsigned)keyBitsize;
+@end
+
+/********* Key Ring ************************/
+
+@protocol NSKeyRing
+- keyForUsageName:(NSString *)user;
+@end
+
+/********** Digital Signatures **************/
+
+// protocol adapted by various signature schemes (FEE, DSA, RSA...)
+@protocol NSDigitalSignature
+- (NSData *)digitalSignatureForData:(NSData *)message;
+ // generate a signature for the data
+
+- (BOOL)isValidDigitalSignature:(NSData *)sig forData:(NSData *)data;
+@end