Secret Information via Blockchain?

[Boosterious]

I think email is a better way to send secret information.
As i know, some president use email to send/receive sensitive information.

Correct,i think OP just want to know about this,and not try to send any letter to his friend. and yes i agree with you,email is better than any secret letter services,but the only one to make sure the security of email is signature and private connection,mportant and secret letter should have better security.

[DimensionZ]

Isn't it a little bit unsafe to send secret messages via the Blockchain as these will stay forever online and everyone will be able to see them? Wouldn't it be better to use an app that deletes every message after been delivered and read like Telegram? Surely we could encrypt and decrypt messages on the Blockchain but I think there are better methods out there for that.

[davinchi]

I think email is a better way to send secret information.
As i know, some president use email to send/receive sensitive information.

Correct,i think OP just want to know about this,and not try to send any letter to his friend. and yes i agree with you,email is better than any secret letter services,but the only one to make sure the security of email is signature and private connection,mportant and secret letter should have better security.

I would have to disagree that email is 'better' than any secret letter services. I mean, it's really easy to get an access and intercept that email using the right tools and commands. Besides, the OP is asking how he could send private information using blockchain, which is apparently I have nearly no idea how.

[~Bitcoin~]

I am doing PGP encryption service provided by https://www.igolder.com/pgp/encryption/
this is great way to send encrypted message. Keybase.io also seems to provide similar service but they have limited invitation to new registration.

[DarkStar_]

The blockchain is public for everyone to see, so it is a dumb idea to send a secret message. This is possible though, by creating an irregular output axript that has the secret message. They could also encrypt it before making it public on the blockchain. Eternitywall is a service you can use to forever store a message on the blockchain and basically does what I mentioned. Check it out.

[Kakmakr]

I think email is a better way to send secret information.
As i know, some president use email to send/receive sensitive information.

Correct,i think OP just want to know about this,and not try to send any letter to his friend. and yes i agree with you,email is better than any secret letter services,but the only one to make sure the security of email is signature and private connection,mportant and secret letter should have better security.

I would have to disagree that email is 'better' than any secret letter services. I mean, it's really easy to get an access and intercept that email using the right tools and commands. Besides, the OP is asking how he could send private information using blockchain, which is apparently I have nearly no idea how.

It depends on what email service you are using, because anything done via Gmail/Yahoo or one of these email providers are compromised from day 1. You could try ProtonMail, but they are under funded and there are rumors that they are working with the US government, to prevent global terrorism.

The Blockchain is too public, and accessible to everyone. ^hmmmmm^

[harrymmmm]

I think email is a better way to send secret information.
As i know, some president use email to send/receive sensitive information.

Correct,i think OP just want to know about this,and not try to send any letter to his friend. and yes i agree with you,email is better than any secret letter services,but the only one to make sure the security of email is signature and private connection,mportant and secret letter should have better security.

I would have to disagree that email is 'better' than any secret letter services. I mean, it's really easy to get an access and intercept that email using the right tools and commands. Besides, the OP is asking how he could send private information using blockchain, which is apparently I have nearly no idea how.

Wow.
I can't see any way to read what you wrote without concluding that you don't know what 'encryption' actually means.
A properly encrypted message can't be 'accessed' no matter what tools are used., assuming you mean access to the plain text.
'Interception' gets you the unreadable encrypted text only, plus maybe the destination (which can be worked around via a drop box, for example).

[biggbox]

A small amount of information can be stored in the block chain using an OP_RETURN transaction.

Hi. What's the max message length that can be stored in OP_RETURN field?

[coins101]

Enigma already solved this problem, back in the 1930s. No need to reinvent the wheel.

Split the message into two. One to set the keys for the decryption; one to send the random message.

I guess if someone is listening for the first message, it'll be public anyway  

[chennan]

Short Question:

Alice and Bob want to tranfer a secret letter. How can they transfer the information with the use of the blockchain?

Thanks!

Why the need for the blockchain?

1) just a secret message transfer:
bob publishes his public key, alice encrypts the message to that key and sends to bob.

2) a secret message transfer with some deniability for both:
as in (1) except alice transfers encrypted message to a dropbox like mailinator

Use of a blockchain would be indicated if you wanted the message to remain around forever, immutable. 
Do you really need this? Possibly you only need the hash of the message to be kept immutable forever?

This... if it's so secretive, then you want the person to read the information as quickly as possible for them to retain the information and then be deleted from existence forever.

There are tons of software/apps out there that allow this type of communication.