context->bufferLen = partInLen);

  return (0);
}

/* Assume partOut buffer is at least 8 bytes.
 */
int R_SealFinal (context, partOut, partOutLen)
R_ENVELOPE_CTX *context;                                         /* context */
unsigned char *partOut;                         /* last encrypted data part */
unsigned int *partOutLen;             /* length of last encrypted data part */
{
  unsigned int padLen;

  /* Pad and encrypt final block.
   */
  padLen = 8 - context->bufferLen;
  R_memset
    ((POINTER)(context->buffer + context->bufferLen), (int)padLen, padLen);
  CipherUpdate (context, partOut, context->buffer, 8);
  *partOutLen = 8;

  /* Restart the context.
   */
  CipherRestart (context);
  context->bufferLen = 0;

  return (0);
}

/* Assume caller has already ASCII decoded the encryptedKey if necessary.
 */
int R_OpenInit
  (context, encryptionAlgorithm, encryptedKey, encryptedKeyLen, iv, privateKey)
R_ENVELOPE_CTX *context;                                     /* new context */
int encryptionAlgorithm;                       /* data encryption algorithm */
unsigned char *encryptedKey;               /* encrypted data encryption key */
unsigned int encryptedKeyLen;                    /* length of encrypted key */
unsigned char iv[8];                               /* initialization vector */
R_RSA_PRIVATE_KEY *privateKey;               /* recipient's RSA private key */
{
  int status;
  unsigned char key[MAX_ENCRYPTED_KEY_LEN];
  unsigned int keyLen;
  
  if (encryptedKeyLen > MAX_ENCRYPTED_KEY_LEN)
    return (RE_LEN);
  
  do {
    context->encryptionAlgorithm = encryptionAlgorithm;

    if (RSAPrivateDecrypt
        (key, &keyLen, encryptedKey, encryptedKeyLen, privateKey)) {
      status = RE_PRIVATE_KEY;
      break;
    }

    if (encryptionAlgorithm == EA_DES_CBC) {    
      if (keyLen != 8) {
        status = RE_PRIVATE_KEY;
        break;
      }
    }
    else {
      if (keyLen != 24) {
        status = RE_PRIVATE_KEY;
        break;
      }
    }
    
    if ((status = CipherInit (context, encryptionAlgorithm, key, iv, 0)) != 0)
      break;

    context->bufferLen = 0;
  } while (0);
  
  /* Zeroize sensitive information.
   */
  R_memset ((POINTER)key, 0, sizeof (key));

  return (status);
}

/* Assume partOut buffer is at least partInLen + 7, since this may flush
     buffered input. Always leaves at least one byte in buffer.
 */
int R_OpenUpdate (context, partOut, partOutLen, partIn, partInLen)
R_ENVELOPE_CTX *context;                                         /* context */
unsigned char *partOut;                         /* next recovered data part */
unsigned int *partOutLen;             /* length of next recovered data part */
unsigned char *partIn;                          /* next encrypted data part */
unsigned int partInLen;               /* length of next encrypted data part */
{
  unsigned int tempLen;

  tempLen = 8 - context->bufferLen;
  if (partInLen <= tempLen) {
    /* Just accumulate into buffer.
     */
    R_memcpy
      ((POINTER)(context->buffer + context->bufferLen), (POINTER)partIn,
       partInLen);
    context->bufferLen += partInLen;
    *partOutLen = 0;
    return (0);
  }

  /* Fill the buffer and decrypt.  We know that there will be more left
       in partIn after decrypting the buffer.
   */
  R_memcpy
    ((POINTER)(context->buffer + context->bufferLen), (POINTER)partIn,
     tempLen);
  CipherUpdate (context, partOut, context->buffer, 8);
  partIn += tempLen;
  partInLen -= tempLen;
  partOut += 8;
  *partOutLen = 8;

  /* Decrypt as many 8 byte blocks as possible, leaving at least one byte
       in partIn.
   */
  tempLen = 8 * ((partInLen - 1) / 8);
  CipherUpdate (context, partOut, partIn, tempLen);
  partIn += tempLen;
  partInLen -= tempLen;
  *partOutLen += tempLen;

  /* Length is between 1 and 8, so copy into buffer.
   */
  R_memcpy
    ((POINTER)context->buffer, (POINTER)partIn,
     context->bufferLen = partInLen);

  return (0);
}

/* Assume partOut buffer is at least 7 bytes.
 */
int R_OpenFinal (context, partOut, partOutLen)
R_ENVELOPE_CTX *context;                                         /* context */
unsigned char *partOut;                         /* last recovered data part */
unsigned int *partOutLen;             /* length of last recovered data part */
{
  int status;
  unsigned char lastPart[8];
  unsigned int padLen;

  status = 0;
  do {
    if (context->bufferLen == 0)
      /* There was no input data to decrypt */
      *partOutLen = 0;
    else {
      if (context->bufferLen != 8) {
        status = RE_KEY;
        break;
      }

      /* Decrypt and strip padding from final block which is in buffer.
       */
      CipherUpdate (context, lastPart, context->buffer, 8);
    
      padLen = lastPart[7];
      if (padLen == 0 || padLen > 8) {
        status = RE_KEY;
        break;
      }
      if (R_memcmp 
          ((POINTER)&lastPart[8 - padLen], PADDING[padLen], padLen) != 0) {
        status = RE_KEY;
        break;
      }
      
      R_memcpy ((POINTER)partOut, (POINTER)lastPart, *partOutLen = 8 - padLen);
    }

    /* Restart the context.
     */
    CipherRestart (context);
    context->bufferLen = 0;
  } while (0);

  /* Zeroize sensitive information.
   */
  R_memset ((POINTER)lastPart, 0, sizeof (lastPart));

  return (status);
}

int R_SignPEMBlock 
  (encodedContent, encodedContentLen, encodedSignature, encodedSignatureLen,
   content, contentLen, recode, digestAlgorithm, privateKey)
unsigned char *encodedContent;                           /* encoded content */
unsigned int *encodedContentLen;               /* length of encoded content */
unsigned char *encodedSignature;                       /* encoded signature */
unsigned int *encodedSignatureLen;           /* length of encoded signature */
unsigned char *content;                                          /* content */
unsigned int contentLen;                               /* length of content */
int recode;                                                /* recoding flag */
int digestAlgorithm;                            /* message-digest algorithm */
R_RSA_PRIVATE_KEY *privateKey;                  /* signer's RSA private key */
{
  int status;
  unsigned char signature[MAX_SIGNATURE_LEN];
  unsigned int signatureLen;
  
  if ((status = R_SignBlock
       (signature, &signatureLen, content, contentLen, digestAlgorithm,
        privateKey)) != 0)
    return (status);

  R_EncodePEMBlock 
    (encodedSignature, encodedSignatureLen, signature, signatureLen);

  if (recode)
    R_EncodePEMBlock
    (encodedContent, encodedContentLen, content, contentLen);

  return (0);
}

int R_SignBlock
  (signature, signatureLen, block, blockLen, digestAlgorithm, privateKey)
unsigned char *signature;                                      /* signature */
unsigned int *signatureLen;                          /* length of signature */
unsigned char *block;                                              /* block */
unsigned int blockLen;                                   /* length of block */
int digestAlgorithm;                            /* message-digest algorithm */
R_RSA_PRIVATE_KEY *privateKey;                  /* signer's RSA private key */
{
  R_SIGNATURE_CTX context;
  int status;

  do {
    if ((status = R_SignInit (&context, digestAlgorithm)) != 0)
      break;
    if ((status = R_SignUpdate (&context, block, blockLen)) != 0)
      break;
    if ((status = R_SignFinal (&context, signature, signatureLen, privateKey))
        != 0)
      break;
  } while (0);

  /* Zeroize sensitive information. */
  R_memset ((POINTER)&context, 0, sizeof (context));

  return (status);
}

int R_VerifyPEMSignature 
  (content, contentLen, encodedContent, encodedContentLen, encodedSignature,
   encodedSignatureLen, recode, digestAlgorithm, publicKey)
unsigned char *content;                                          /* content */
unsigned int *contentLen;                              /* length of content */
unsigned char *encodedContent;                /* (possibly) encoded content */
unsigned int encodedContentLen;                /* length of encoded content */
unsigned char *encodedSignature;                       /* encoded signature */
unsigned int encodedSignatureLen;            /* length of encoded signature */
int recode;                                                /* recoding flag */
int digestAlgorithm;                            /* message-digest algorithm */
R_RSA_PUBLIC_KEY *publicKey;                     /* signer's RSA public key */
{
  unsigned char signature[MAX_SIGNATURE_LEN];
  unsigned int signatureLen;
  
  if (encodedSignatureLen > MAX_PEM_SIGNATURE_LEN)
    return (RE_SIGNATURE_ENCODING);
  
  if (recode) {
    if (R_DecodePEMBlock
        (content, contentLen, encodedContent, encodedContentLen))
      return (RE_CONTENT_ENCODING);
  }
  else {
    content = encodedContent;
    *contentLen = encodedContentLen;
  }
    
  if (R_DecodePEMBlock
      (signature, &signatureLen, encodedSignature, encodedSignatureLen))
    return (RE_SIGNATURE_ENCODING);
  
  return (R_VerifyBlockSignature 
          (content, *contentLen, signature, signatureLen, digestAlgorithm,
           publicKey));
}

int R_VerifyBlockSignature 
  (block, blockLen, signature, signatureLen, digestAlgorithm, publicKey)
unsigned char *block;                                              /* block */
unsigned int blockLen;                                   /* length of block */
unsigned char *signature;                                      /* signature */
unsigned int signatureLen;                           /* length of signature */
int digestAlgorithm;                            /* message-digest algorithm */
R_RSA_PUBLIC_KEY *publicKey;                     /* signer's RSA public key */
{
  R_SIGNATURE_CTX context;
  int status;

  do {
    if ((status = R_VerifyInit (&context, digestAlgorithm)) != 0)
      break;
    if ((status = R_VerifyUpdate (&context, block, blockLen)) != 0)
      break;
    if ((status = R_VerifyFinal (&context, signature, signatureLen, publicKey))
        != 0)
      break;
  } while (0);

  /* Zeroize sensitive information. */
  R_memset ((POINTER)&context, 0, sizeof (context));

  return (status);
}

int R_SealPEMBlock 
  (encryptedContent, encryptedContentLen, encryptedKey, encryptedKeyLen,
   encryptedSignature, encryptedSignatureLen, iv, content, contentLen,
   digestAlgorithm, publicKey, privateKey, randomStruct)
unsigned char *encryptedContent;              /* encoded, encrypted content */
unsigned int *encryptedContentLen;                                /* length */